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Pei-jin Zhou - One of the best experts on this subject based on the ideXlab platform.
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haloplanus vescus sp nov an extremely halophilic archaeon from a marine solar saltern and emended description of the genus haloplanus
International Journal of Systematic and Evolutionary Microbiology, 2010Co-Authors: Heng-lin Cui, Hongcan Liu, Xia Gao, Yuguang Zhou, Pei-jin ZhouAbstract:An extremely halophilic archaeon, strain RO5-8T, was isolated from a disused marine solar saltern in China. The cells were pleomorphic and flat. In static liquid medium, cells floated to the surface. Strain RO5-8T stained Gram-negative and colonies were pink-pigmented. It was able to grow at 30–50 °C (optimum 40 °C), at 2.6–4.3 M NaCl (optimum 3.1 M NaCl), at 0.03–0.5 M MgCl2 (optimum 0.03 M MgCl2) and at pH 5.5–7.5 (optimum pH 6.0–6.5). Cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 12 % (w/v). The major polar lipids of strain RO5-8T were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and one major glycolipid chromatographically identical to the sulfated mannosyl glucosyl diether S-DGD-1. On the basis of 16S rRNA gene sequence analysis, strain RO5-8T was closely related to three strains of Haloplanus natans with similarities of 97.3–97.6 %. The DNA G+C content of strain RO5-8T was 62.1 mol%. The DNA–DNA hybridization value between strain RO5-8T and Haloplanus natans JCM 14081T was 51.6 %. It was concluded that strain RO5-8T represents a novel species of the genus Haloplanus, for which the name Haloplanus vescus sp. nov. is proposed. The type strain is RO5-8T (=CGMCC 1.8712T =JCM 16055T).
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haladaptatus litoreus sp nov an extremely halophilic archaeon from a marine solar saltern and emended description of the genus haladaptatus
International Journal of Systematic and Evolutionary Microbiology, 2010Co-Authors: Heng-lin Cui, Hongcan Liu, Ying Dong, Xia Gao, Yuguang Zhou, Fangfang Sun, Aharon Oren, Pei-jin ZhouAbstract:Two extremely halophilic archaea, strains RO1-28T and RO1-22, were isolated from a marine solar saltern in Jiangsu, China. Both strains required at least 0.05 M Mg2+ and 1.7 M NaCl for growth. They were able to grow over a pH range of 6.0–8.5 and a temperature range of 25–55 °C, with optimal pH of 7.0 and optimal temperature of 37–40 °C. Based on 16S rRNA gene sequence analysis, strains RO1-28T and RO1-22 were closely related to Haladaptatus paucihalophilus, the single species of the genus Haladaptatus, with similarities of 94.0–95.2 %. The major polar lipids of the two strains were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and three glycolipids chromatographically identical to the glycolipids of Haladaptatus paucihalophilus JCM 13897T. Both strains RO1-28T and RO1-22 had a DNA G+C content of 54.0 mol% (HPLC). The DNA–DNA hybridization value between the two strains was more than 70 % (92 %) and both strains showed low levels of DNA–DNA relatedness (32 % and 33 %) with Haladaptatus paucihalophilus JCM 13897T. It was concluded that strains RO1-28T and RO1-22 represent a novel species of the genus Haladaptatus, for which the name Haladaptatus litoreus sp. nov. is proposed. The type strain is RO1-28T (=CGMCC 1.7737T =JCM 15771T).
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Halorubrum litoreum sp. nov., an extremely halophilic archaeon from a solar saltern.
International Journal of Systematic and Evolutionary Microbiology, 2007Co-Authors: Heng-lin Cui, Pei-jin Zhou, Ze-ying Lin, Ying Dong, Shuang-jiang LiuAbstract:An extremely halophilic archaeon, strain Fa-1(T), was isolated from a marine solar saltern in Fujian, China. Strain Fa-1(T) required Mg2+ and at least 2.0 M NaCl for growth. It was able to grow at pH 6.5-9.0 (optimally at pH 7.0-7.5) and at 20-55 degrees C (optimally at 37-42 degrees C). The major polar lipids of strain Fa-1(T) were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and a sulfated diglycosyl diether. On the basis of a 16S rRNA gene sequence analysis, strain Fa-1(T) was closely related to nine species of the genus Halorubrum, showing sequence similarities of 97.4-98.4 %. The G+C content of the DNA of strain Fa-1(T) is 64.9 mol% (Tm). DNA-DNA hybridization values between strain Fa-1(T) and the most closely related members of the genus Halorubrum were below 51 %. On the basis of the data from this study, strain Fa-1(T) represents a novel species of the genus Halorubrum, for which the name Halorubrum litoreum sp. nov. is proposed. The type strain is Fa-1(T) (=CGMCC 1.5336(T) =JCM 13561(T)).
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halobacterium jilantaiense sp nov a halophilic archaeon isolated from a saline lake in inner mongolia china
International Journal of Systematic and Evolutionary Microbiology, 2006Co-Authors: Yong Yang, Pei-jin ZhouAbstract:A novel halophilic archaeon, NG4T, was isolated from Jilantai salt lake in Inner Mongolia, China. The taxonomy of strain NG4T was studied by polyphasic methods. Strain NG4T grew at pH 5.5–8.5 and at a temperature of 22–55 °C. It was chemo-organotrophic, aerobic and required concentrations of 2.7–5.2 M NaCl and 0.05–0.3 M Mg2+ for growth. Cells were Gram-negative, slender rods. Colonies on agar plates containing 25 % (w/v) total salts were red, elevated and round. According to 16S rRNA gene sequence similarity, strain NG4T was phylogenetically related to Halobacterium salinarum DSM 3754T (98.2 %) and Halobacterium noricense A1T (97.3 %). The DNA G+C content was 64.2 mol%. DNA–DNA relatedness values with Hbt. salinarum DSM 3754T and Hbt. noricense A1T were 47 and 35 %, respectively. The polar lipids of strain NG4T consisted of Phosphatidylglycerol, methylated Phosphatidylglycerol phosphate, Phosphatidylglycerol sulfate, triglycosyl diether, sulfated triglycosyl diether and sulfated tetraglycosyl diether. It was concluded that strain NG4T represents a novel species of the genus Halobacterium, for which the name Halobacterium jilantaiense sp. nov. is proposed. The type strain is NG4T (=CGMCC 1.5337T=JCM 13558T).
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halobacterium jilantaiense sp nov a halophilic archaeon isolated from a saline lake in inner mongolia china
International Journal of Systematic and Evolutionary Microbiology, 2006Co-Authors: Yong Yang, Pei-jin Zhou, Heng-lin Cui, Shuang-jiang LiuAbstract:A novel halophilic archaeon, NG4(T), was isolated from Jilantai salt lake in Inner Mongolia, China. The taxonomy of strain NG4(T) was studied by polyphasic methods. Strain NG4(T) grew at pH 5.5-8.5 and at a temperature of 22-55 degrees C. It was chemo-organotrophic, aerobic and required concentrations of 2.7-5.2 M NaCl and 0.05-0.3 M Mg(2+) for growth. Cells were Gram-negative, slender rods. Colonies on agar plates containing 25 % (w/v) total salts were red, elevated and round. According to 16S rRNA gene sequence similarity, strain NG4(T) was phylogenetically related to Halobacterium salinarum DSM 3754(T) (98.2 %) and Halobacterium noricense A1(T) (97.3 %). The DNA G+C content was 64.2 mol%. DNA-DNA relatedness values with Hbt. salinarum DSM 3754(T) and Hbt. noricense A1(T) were 47 and 35 %, respectively. The polar lipids of strain NG4(T) consisted of Phosphatidylglycerol, methylated Phosphatidylglycerol phosphate, Phosphatidylglycerol sulfate, triglycosyl diether, sulfated triglycosyl diether and sulfated tetraglycosyl diether. It was concluded that strain NG4(T) represents a novel species of the genus Halobacterium, for which the name Halobacterium jilantaiense sp. nov. is proposed. The type strain is NG4(T) (=CGMCC 1.5337(T)=JCM 13558(T)).
Shuang-jiang Liu - One of the best experts on this subject based on the ideXlab platform.
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Halorubrum litoreum sp. nov., an extremely halophilic archaeon from a solar saltern.
International Journal of Systematic and Evolutionary Microbiology, 2007Co-Authors: Heng-lin Cui, Pei-jin Zhou, Ze-ying Lin, Ying Dong, Shuang-jiang LiuAbstract:An extremely halophilic archaeon, strain Fa-1(T), was isolated from a marine solar saltern in Fujian, China. Strain Fa-1(T) required Mg2+ and at least 2.0 M NaCl for growth. It was able to grow at pH 6.5-9.0 (optimally at pH 7.0-7.5) and at 20-55 degrees C (optimally at 37-42 degrees C). The major polar lipids of strain Fa-1(T) were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and a sulfated diglycosyl diether. On the basis of a 16S rRNA gene sequence analysis, strain Fa-1(T) was closely related to nine species of the genus Halorubrum, showing sequence similarities of 97.4-98.4 %. The G+C content of the DNA of strain Fa-1(T) is 64.9 mol% (Tm). DNA-DNA hybridization values between strain Fa-1(T) and the most closely related members of the genus Halorubrum were below 51 %. On the basis of the data from this study, strain Fa-1(T) represents a novel species of the genus Halorubrum, for which the name Halorubrum litoreum sp. nov. is proposed. The type strain is Fa-1(T) (=CGMCC 1.5336(T) =JCM 13561(T)).
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halobacterium jilantaiense sp nov a halophilic archaeon isolated from a saline lake in inner mongolia china
International Journal of Systematic and Evolutionary Microbiology, 2006Co-Authors: Yong Yang, Pei-jin Zhou, Heng-lin Cui, Shuang-jiang LiuAbstract:A novel halophilic archaeon, NG4(T), was isolated from Jilantai salt lake in Inner Mongolia, China. The taxonomy of strain NG4(T) was studied by polyphasic methods. Strain NG4(T) grew at pH 5.5-8.5 and at a temperature of 22-55 degrees C. It was chemo-organotrophic, aerobic and required concentrations of 2.7-5.2 M NaCl and 0.05-0.3 M Mg(2+) for growth. Cells were Gram-negative, slender rods. Colonies on agar plates containing 25 % (w/v) total salts were red, elevated and round. According to 16S rRNA gene sequence similarity, strain NG4(T) was phylogenetically related to Halobacterium salinarum DSM 3754(T) (98.2 %) and Halobacterium noricense A1(T) (97.3 %). The DNA G+C content was 64.2 mol%. DNA-DNA relatedness values with Hbt. salinarum DSM 3754(T) and Hbt. noricense A1(T) were 47 and 35 %, respectively. The polar lipids of strain NG4(T) consisted of Phosphatidylglycerol, methylated Phosphatidylglycerol phosphate, Phosphatidylglycerol sulfate, triglycosyl diether, sulfated triglycosyl diether and sulfated tetraglycosyl diether. It was concluded that strain NG4(T) represents a novel species of the genus Halobacterium, for which the name Halobacterium jilantaiense sp. nov. is proposed. The type strain is NG4(T) (=CGMCC 1.5337(T)=JCM 13558(T)).
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natrinema altunense sp nov an extremely halophilic archaeon isolated from a salt lake in altun mountain in xinjiang china
International Journal of Systematic and Evolutionary Microbiology, 2005Co-Authors: Peigen Ren, Shuang-jiang Liu, Pei-jin ZhouAbstract:A novel extremely halophilic strain, AJ2(T), was isolated from Ayakekum salt lake located in the Altun Mountain National Nature Reserve in Xinjiang, China. This isolate was neutrophilic, motile and grew in a wide range of MgCl(2) concentrations (0.005-1.0 M). The major polar lipids of the isolate were C(20)C(20) and C(20)C(25) derivatives of Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester and Phosphatidylglycerol sulfate. A comprehensive 16S rRNA gene sequence analysis revealed that the isolate shared 96.6-97.7 % sequence identity with Natrinema species. The isolate, however, could be genetically differentiated from these species by DNA-DNA hybridization analysis and on the basis of its physiological properties. On the basis of the polyphasic evidence, strain AJ2(T) (= AS 1.3731(T) = JCM 12890(T)) represents the type strain of a novel species, for which the name Natrinema altunense sp. nov. is proposed.
Antonio Ventosa - One of the best experts on this subject based on the ideXlab platform.
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natronomonas salsuginis sp nov a new inhabitant of a marine solar saltern
Microorganisms, 2020Co-Authors: Ana Duranviseras, Cristina Sanchezporro, Antonio VentosaAbstract:A halophilic archaeon, strain F20-122T, was isolated from a marine saltern of Isla Bacuta (Huelva, Spain). Cells were Gram-stain-negative, aerobic, and coccoid in morphology. It grew at 25-50 °C (optimum 37 °C), pH 6.5-9.0 (optimum pH 8.0), and 10-30% (w/v) total salts (optimum 25% salts). The phylogenetic analyses based on the 16S rRNA and rpoB' genes showed its affiliation with the genus Natronomonas and suggested its placement as a new species within this genus. The in silico DNA-DNA hybridization (DDH) and average nucleotide identity (ANI) analyses of this strain against closely related species supported its placement in a new taxon. The DNA G + C content of this isolate was 63.0 mol%. The polar lipids of strain F20-122T were Phosphatidylglycerol phosphate methyl ester (PGP-Me), Phosphatidylglycerol (PG), and Phosphatidylglycerol sulfate (PGS). Traces of biPhosphatidylglycerol (BPG) and other minor phospholipids and unidentified glycolipids were also present. Based on the phylogenetic, genomic, phenotypic, and chemotaxonomic characterization, we propose strain F20-122T (= CCM 8891T = CECT 9564T = JCM 33320T) as the type strain of a new species within the genus Natronomonas, with the name Natronomonas salsuginis sp. nov. Rhodopsin-like sequence analysis of strain F20-122T revealed the presence of haloarchaeal proton pumps, suggesting a lightmediated ATP synthesis for this strain and a maximum wavelength absorption in the green spectrum.
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halorubrum halodurans sp nov an extremely halophilic archaeon isolated from a hypersaline lake
International Journal of Systematic and Evolutionary Microbiology, 2016Co-Authors: Paulina Corral, Rafael R. De La Haba, Mohammad Ali Amoozegar, Cristina Sanchezporro, Thane R Papke, Antonio VentosaAbstract:Two extremely halophilic archaea, strains Cb34T and C170, belonging to the genus Halorubrum, were isolated from the brine of the hypersaline lake Aran-Bidgol in Iran. Cells of the two strains were motile, pleomorphic rods, stained Gram-variable and produced red-pigmented colonies. Strains Cb34T and C170 required 25 % (w/v) salts, pH 7.0 and 37 °C for optimal growth under aerobic conditions; 0.3 M Mg2+ was required. Cells of both isolates were lysed in distilled water and hypotonic treatment with < 10 % NaCl provoked cell lysis. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that these two strains were closely related to Halorubrum cibi B31T (98.8 %) and other members of the genus Halorubrum. In addition, studies based on the rpoB' gene revealed that strains Cb34T and C170 are placed among the species of Halorubrum and are closely related to Halorubrum cibi B31T, with rpoB' gene sequence similarity less than or equal to 95.7 %. The polar lipid patterns of both strains consisted of Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and sulfated mannosyl glucosyl diether. The DNA G+C content was 62.1-62.4 mol%. DNA-DNA hybridization studies confirmed that strains Cb34T and C170 constitute a distinct species. Data obtained in this study show that the two strains represent a novel species, for which the name Halorubrum halodurans sp. nov. is proposed. The type strain is Cb34T ( = CECT 8745T = IBRC-M 10233T).
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Halorubrum persicum sp. nov., an extremely halophilic archaeon isolated from sediment of a hypersaline lake
International Journal of Systematic and Evolutionary Microbiology, 2015Co-Authors: Paulina Corral, Rafael R. De La Haba, Cristina Sánchez-porro, Mohammad Ali Amoozegar, R. Thane Papke, Antonio VentosaAbstract:An extremely halophilic archaeon belonging to the genus Halorubrum , strain C49T, was isolated from sediment of the hypersaline lake Aran-Bidgol in Iran. Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain C49T was closely related to Halorubrum saccharovorum JCM 8865T (99.5 %) and other species of the genus Halorubrum . Studies based on multilocus sequence analysis revealed that strain C49T is placed among the species of Halorubrum ; the strain constituted a defined branch in comparison with the type strains of species of Halorubrum , while the 16S rRNA gene sequence divergence could not define the status of the newly isolated strain. For optimum growth, strain C49T required 20 % (w/v) salts at pH 7.0 and 37 °C under aerobic conditions. Mg2+ was not required. The cells were pleomorphic rods, motile and stained Gram-variable. Colonies of the strain were pink. Hypotonic treatment with <12 % NaCl provoked cell lysis. The polar lipid pattern of strain C49T consisted of Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester derived from both C20C20 and C20C25 archaeol, Phosphatidylglycerol sulfate and sulfated mannosyl glucosyl diether. The DNA G+C content was 64.2 mol%. DNA–DNA hybridization studies and average nucleotide identity confirmed that strain C49T constitutes a distinct genospecies. Data obtained in this study show that strain C49T represents a novel species, for which the name Halorubrum persicum sp. nov. is proposed. The type strain is C49T ( = IBRC-M 10232T = JCM 30541T).
Heng-lin Cui - One of the best experts on this subject based on the ideXlab platform.
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haloplanus vescus sp nov an extremely halophilic archaeon from a marine solar saltern and emended description of the genus haloplanus
International Journal of Systematic and Evolutionary Microbiology, 2010Co-Authors: Heng-lin Cui, Hongcan Liu, Xia Gao, Yuguang Zhou, Pei-jin ZhouAbstract:An extremely halophilic archaeon, strain RO5-8T, was isolated from a disused marine solar saltern in China. The cells were pleomorphic and flat. In static liquid medium, cells floated to the surface. Strain RO5-8T stained Gram-negative and colonies were pink-pigmented. It was able to grow at 30–50 °C (optimum 40 °C), at 2.6–4.3 M NaCl (optimum 3.1 M NaCl), at 0.03–0.5 M MgCl2 (optimum 0.03 M MgCl2) and at pH 5.5–7.5 (optimum pH 6.0–6.5). Cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 12 % (w/v). The major polar lipids of strain RO5-8T were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and one major glycolipid chromatographically identical to the sulfated mannosyl glucosyl diether S-DGD-1. On the basis of 16S rRNA gene sequence analysis, strain RO5-8T was closely related to three strains of Haloplanus natans with similarities of 97.3–97.6 %. The DNA G+C content of strain RO5-8T was 62.1 mol%. The DNA–DNA hybridization value between strain RO5-8T and Haloplanus natans JCM 14081T was 51.6 %. It was concluded that strain RO5-8T represents a novel species of the genus Haloplanus, for which the name Haloplanus vescus sp. nov. is proposed. The type strain is RO5-8T (=CGMCC 1.8712T =JCM 16055T).
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haladaptatus litoreus sp nov an extremely halophilic archaeon from a marine solar saltern and emended description of the genus haladaptatus
International Journal of Systematic and Evolutionary Microbiology, 2010Co-Authors: Heng-lin Cui, Hongcan Liu, Ying Dong, Xia Gao, Yuguang Zhou, Fangfang Sun, Aharon Oren, Pei-jin ZhouAbstract:Two extremely halophilic archaea, strains RO1-28T and RO1-22, were isolated from a marine solar saltern in Jiangsu, China. Both strains required at least 0.05 M Mg2+ and 1.7 M NaCl for growth. They were able to grow over a pH range of 6.0–8.5 and a temperature range of 25–55 °C, with optimal pH of 7.0 and optimal temperature of 37–40 °C. Based on 16S rRNA gene sequence analysis, strains RO1-28T and RO1-22 were closely related to Haladaptatus paucihalophilus, the single species of the genus Haladaptatus, with similarities of 94.0–95.2 %. The major polar lipids of the two strains were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and three glycolipids chromatographically identical to the glycolipids of Haladaptatus paucihalophilus JCM 13897T. Both strains RO1-28T and RO1-22 had a DNA G+C content of 54.0 mol% (HPLC). The DNA–DNA hybridization value between the two strains was more than 70 % (92 %) and both strains showed low levels of DNA–DNA relatedness (32 % and 33 %) with Haladaptatus paucihalophilus JCM 13897T. It was concluded that strains RO1-28T and RO1-22 represent a novel species of the genus Haladaptatus, for which the name Haladaptatus litoreus sp. nov. is proposed. The type strain is RO1-28T (=CGMCC 1.7737T =JCM 15771T).
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Halorubrum litoreum sp. nov., an extremely halophilic archaeon from a solar saltern.
International Journal of Systematic and Evolutionary Microbiology, 2007Co-Authors: Heng-lin Cui, Pei-jin Zhou, Ze-ying Lin, Ying Dong, Shuang-jiang LiuAbstract:An extremely halophilic archaeon, strain Fa-1(T), was isolated from a marine solar saltern in Fujian, China. Strain Fa-1(T) required Mg2+ and at least 2.0 M NaCl for growth. It was able to grow at pH 6.5-9.0 (optimally at pH 7.0-7.5) and at 20-55 degrees C (optimally at 37-42 degrees C). The major polar lipids of strain Fa-1(T) were Phosphatidylglycerol, Phosphatidylglycerol phosphate methyl ester, Phosphatidylglycerol sulfate and a sulfated diglycosyl diether. On the basis of a 16S rRNA gene sequence analysis, strain Fa-1(T) was closely related to nine species of the genus Halorubrum, showing sequence similarities of 97.4-98.4 %. The G+C content of the DNA of strain Fa-1(T) is 64.9 mol% (Tm). DNA-DNA hybridization values between strain Fa-1(T) and the most closely related members of the genus Halorubrum were below 51 %. On the basis of the data from this study, strain Fa-1(T) represents a novel species of the genus Halorubrum, for which the name Halorubrum litoreum sp. nov. is proposed. The type strain is Fa-1(T) (=CGMCC 1.5336(T) =JCM 13561(T)).
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halobacterium jilantaiense sp nov a halophilic archaeon isolated from a saline lake in inner mongolia china
International Journal of Systematic and Evolutionary Microbiology, 2006Co-Authors: Yong Yang, Pei-jin Zhou, Heng-lin Cui, Shuang-jiang LiuAbstract:A novel halophilic archaeon, NG4(T), was isolated from Jilantai salt lake in Inner Mongolia, China. The taxonomy of strain NG4(T) was studied by polyphasic methods. Strain NG4(T) grew at pH 5.5-8.5 and at a temperature of 22-55 degrees C. It was chemo-organotrophic, aerobic and required concentrations of 2.7-5.2 M NaCl and 0.05-0.3 M Mg(2+) for growth. Cells were Gram-negative, slender rods. Colonies on agar plates containing 25 % (w/v) total salts were red, elevated and round. According to 16S rRNA gene sequence similarity, strain NG4(T) was phylogenetically related to Halobacterium salinarum DSM 3754(T) (98.2 %) and Halobacterium noricense A1(T) (97.3 %). The DNA G+C content was 64.2 mol%. DNA-DNA relatedness values with Hbt. salinarum DSM 3754(T) and Hbt. noricense A1(T) were 47 and 35 %, respectively. The polar lipids of strain NG4(T) consisted of Phosphatidylglycerol, methylated Phosphatidylglycerol phosphate, Phosphatidylglycerol sulfate, triglycosyl diether, sulfated triglycosyl diether and sulfated tetraglycosyl diether. It was concluded that strain NG4(T) represents a novel species of the genus Halobacterium, for which the name Halobacterium jilantaiense sp. nov. is proposed. The type strain is NG4(T) (=CGMCC 1.5337(T)=JCM 13558(T)).
Phedra Marius - One of the best experts on this subject based on the ideXlab platform.
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probing the interaction of lipids with the non annular binding sites of the potassium channel kcsa by magic angle spinning nmr
Biochimica et Biophysica Acta, 2012Co-Authors: Phedra Marius, Maurits R R De Planque, Philip T F WilliamsonAbstract:The activity of the potassium channel KcsA is tightly regulated through the interactions of anionic lipids with high-affinity non-annular lipid binding sites located at the interface between the channel's subunits. Here we present solid-state phosphorous NMR studies that resolve the negatively charged lipid Phosphatidylglycerol within the non-annular lipid-binding site. Perturbations in chemical shift observed upon the binding of Phosphatidylglycerol are indicative of the interaction of positively charged sidechains within the non-annular binding site and the negatively charged lipid headgroup. Site directed mutagenesis studies have attributed these charge interactions to R64 and R89. Functionally the removal of the positive charges from R64 and R89 appears to act synergistically to reduce the probability of channel opening.
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binding of anionic lipids to at least three nonannular sites on the potassium channel kcsa is required for channel opening
Biophysical Journal, 2008Co-Authors: Phedra Marius, Michele Zagnoni, Mairi E Sandison, Malcolm J East, Hywel Morgan, A G LeeAbstract:In addition to the annular or boundary lipids that surround the transmembrane surface of the potassium channel KcsA from Streptomyces lividans, x-ray crystallographic studies have detected one anionic lipid molecule bound at each protein-protein interface in the homotetrameric structure, at sites referred to as nonannular sites. The binding constant for Phosphatidylglycerol at the nonannular sites has been determined using fluorescence quenching methods with a mutant of KcsA lacking the normal three lipid-exposed Trp residues. Binding is weak, with a binding constant of 0.42 +/- 0.06 in units of mol fraction, implying that the nonannular sites will only be approximately 70% occupied in bilayers of 100% Phosphatidylglycerol. However, the nonannular sites show high selectivity for anionic lipids over zwitterionic lipids, and it is suggested that a change in packing at the protein-protein interface leads to a closing of the nonannular binding site in the unbound state. Increasing the anionic lipid content of the membrane leads to a large increase in open channel probability, from approximately 2.5% in the presence of 25 mol % Phosphatidylglycerol to approximately 62% in 100 mol % Phosphatidylglycerol. The relationship between open channel probability and Phosphatidylglycerol content shows cooperativity. The data are consistent with a model in which three or four of the four nonannular sites in the KcsA homotetramer have to be occupied by anionic lipid for the channel to open. The conductance of the open channel increases with increasing concentration of anionic lipid, an effect possibly due to effects of anionic lipid on the concentration of K(+) close to the membrane surface.
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the interfacial lipid binding site on the potassium channel kcsa is specific for anionic phospholipids
Biophysical Journal, 2005Co-Authors: Phedra Marius, Malcolm J East, Simon J Alvis, A G LeeAbstract:Lipid binding to the potassium channel KcsA from Streptomyces lividans has been studied using quenching of the fluorescence of Trp residues by brominated phospholipids. It is shown that binding of phospholipids to nonannular lipid binding sites on KcsA, located one each at the four protein-protein interfaces in the tetrameric structure, is specific for anionic phospholipids, zwitterionic phosphatidylcholine being unable to bind at the sites. The binding constant for Phosphatidylglycerol of 3.0 ± 0.7 mol fraction−1 means that in a membrane containing ∼20 mol% Phosphatidylglycerol, as in the Escherichia coli inner membrane, the nonannular sites will be ∼37% occupied by Phosphatidylglycerol. The binding constant for phosphatidic acid is similar to that for Phosphatidylglycerol but binding constants for phosphatidylserine and cardiolipin are about double those for Phosphatidylglycerol. Binding to annular sites around the circumference of the KcsA tetramer are different on the extracellular and intracellular faces of the membrane. On the extracellular face of the membrane the binding constants for anionic lipids are similar to those for phosphatidylcholine, the lack of specificity being consistent with the lack of any marked clusters of charged residues on KcsA close to the membrane on the extracellular side. In contrast, binding to annular sites on the intracellular side of the membrane shows a distinct structural specificity, with binding of phosphatidic acid and Phosphatidylglycerol being stronger than binding of phosphatidylcholine, whereas binding constants for phosphatidylserine and cardiolipin are similar to that for phosphatidylcholine. It is suggested that this pattern of binding follows from the pattern of charge distribution on KcsA on the intracellular side of the membrane.