The Experts below are selected from a list of 1446 Experts worldwide ranked by ideXlab platform
A. Bacher - One of the best experts on this subject based on the ideXlab platform.
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the lumazine synthase riboflavin synthase complex shapes and functions of a highly variable enzyme system
FEBS Journal, 2013Co-Authors: Rudolf Ladenstein, A. Bacher, Markus FischerAbstract:The xylene ring of riboflavin (vitamin B2) is assembled from two molecules of 3,4-dihydroxy-2-butanone 4-phosphate by a mechanistically complex process that is jointly catalyzed by lumazine synthase and riboflavin synthase. In Bacillaceae, these enzymes form a structurally unique complex comprising an icosahedral shell of 60 lumazine synthase subunits and a core of three riboflavin synthase subunits, whereas many other bacteria have empty lumazine synthase capsids, fungi, Archaea and some eubacteria have pentameric lumazine synthases, and the riboflavin synthases of Archaea are paralogs of lumazine synthase. The structures of the molecular ensembles have been studied in considerable detail by X-ray crystallography, X-ray small-angle scattering and electron microscopy. However, certain mechanistic aspects remain unknown. Surprisingly, the quaternary structure of the icosahedral β subunit capsids undergoes drastic changes, resulting in formation of large, quasi-spherical capsids; this process is modulated by sequence mutations. The occurrence of large shells consisting of 180 or more lumazine synthase subunits has recently generated interest for protein engineering topics, particularly the construction of encapsulation systems.
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Biosynthesis of riboflavin: lumazine synthase and riboflavin synthase.
Methods in Enzymology, 1997Co-Authors: A. Bacher, Sabine Eberhardt, Markus Fischer, Simone Mörtl, Klaus Kis, Karl Kugelbrey, Johannes Scheuring, Schott KAbstract:Publisher Summary This chapter discusses the biosynthesis of riboflavin. 6,7-Dimethyl-8-ribityllumazine is developed as the direct biosynthetic precursor of riboflavin. The lumazine derivative is converted to riboflavin by the enzyme riboflavin synthase. The reaction involves the transfer of a four-carbon unit between two identical substrate molecules in an unusual dismutation reaction. The lumazine is biosynthesized from 5-amino-6-ribitylamino-2,4 (1 H ,3 H )-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate by the enzyme lumazine synthase. The riboflavin synthases of Bacillus subtilis and Escherichia coli are homotrimeric molecules. Members of the Bacillaceae also form a large multimeric enzyme complex with lumazine synthase and riboflavin synthase activity. This complex accounts for 12–40% of the total riboflavin synthase activity in different members of the Bacillaceae. This enzyme complex has been designated “heavy riboflavin synthase.” The protein consists of 60 β subunits (lumazine synthase) that form an icosahedral capsid containing 3 α subunits (riboflavin synthase). The structure of this complex is presented in the chapter.
Yong-ha Park - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic analysis of the genus thermoactinomyces based on 16s rdna sequences
International Journal of Systematic and Evolutionary Microbiology, 2000Co-Authors: Jung-hoon Yoon, Yong-ha ParkAbstract:The almost complete 16S rDNA sequences of the type strains of eight validly described species and two invalid species of the genus Thermoactinomyces were determined and phylogenetically analysed. The validly described Thermoactinomyces species formed phylogenetic lineages related to the family Bacillaceae, as shown previously. However, the available strains of 'Thermoactinomyces glaucus' and 'Thermoactinomyces monosporus' exhibited their closest phylogenetic affinities not to the genus Thermoactinomyces but to the genus Saccharomonospora. Some Thermoactinomyces species were shown to be closely related from 16S rDNA sequence analysis. Particularly, Thermoactinomyces vulgaris KCTC 9076T and Thermoactinomyces candidus KCTC 9557T had the same 16S rDNA sequences and Thermoactinomyces thalpophilus KCTC 9789T and Thermoactinomyces sacchari KCTC 9790T showed 16S rDNA similarity value of almost 100%. From phylogenetic analysis based on 16S rDNA sequences, it is suggested that the genus Thermoactinomyces should be taxonomically re-evaluated using other useful taxonomic markers.
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Phylogenetic analysis of the genus Thermoactinomyces based on 16S rDNA sequences
Society for General Microbiology, 2000Co-Authors: Jung-hoon Yoon, Yong-ha ParkAbstract:The almost complete 16S rDNA sequences of the type strains of eight validly described species and two invalid species of the genus Thermoactinomyces were determined and phylogenetically analysed. The validly described Thermoactinomyces species formed phylogenetic lineages related to the family Bacillaceae, as shown previously. However, the available strains of 'Thermoactinomyces glaucus' and 'Thermoactinomyces monosporus' exhibited their closest phylogenetic affinities not to the genus Thermoactinomyces but to the genus Saccharomonospora. Some Thermoactinomyces species were shown to be closely related from 16S rDNA sequence analysis. Particularly, Thermoactinomyces vulgaris KCTC 9076(T) and Thermoactinomyces candidus KCTC 9557(T) had the same 16S rDNA sequences and Thermoactinomyces thalpophilus KCTC 9789(T) and Thermoactinomyces sacchari KCTC 9790(T) showed 16S rDNA similarity value of almost 100%. From phylogenetic analysis based on 16S rDNA sequences, it is suggested that the genus Thermoactinomyces should be taxonomically re-evaluated using other useful taxonomic markers.ope
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suprageneric classification of thermoactinomyces vulgaris by nucleotide sequencing of 5s ribosomal rna
Zentralblatt Fur Bakteriologie-international Journal of Medical Microbiology Virology Parasitology and Infectious Diseases, 1993Co-Authors: Yong-ha Park, Tae Ick MheenAbstract:Summary The 5S rRNA nucleotide sequence of Thermoactinomyces vulgaris was determined and compared with published sequences of representative Gram-positive bacteria. The primary and secondary structure of the sequence is of the type characteristic of Gram-positive bacteria that have DNA with a low proportion of guanine plus cytosine. It was evident from the phylogenetic trees that T. vulgaris has little in common with actinomycetes but is related to the genus Bacillus , showing a moderately high relationship with B. stearothermophilus . The taxonomic implications of these relationships are discussed and an emended description of the family Bacillaceae is given.
Schott K - One of the best experts on this subject based on the ideXlab platform.
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Biosynthesis of riboflavin: lumazine synthase and riboflavin synthase.
Methods in Enzymology, 1997Co-Authors: A. Bacher, Sabine Eberhardt, Markus Fischer, Simone Mörtl, Klaus Kis, Karl Kugelbrey, Johannes Scheuring, Schott KAbstract:Publisher Summary This chapter discusses the biosynthesis of riboflavin. 6,7-Dimethyl-8-ribityllumazine is developed as the direct biosynthetic precursor of riboflavin. The lumazine derivative is converted to riboflavin by the enzyme riboflavin synthase. The reaction involves the transfer of a four-carbon unit between two identical substrate molecules in an unusual dismutation reaction. The lumazine is biosynthesized from 5-amino-6-ribitylamino-2,4 (1 H ,3 H )-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate by the enzyme lumazine synthase. The riboflavin synthases of Bacillus subtilis and Escherichia coli are homotrimeric molecules. Members of the Bacillaceae also form a large multimeric enzyme complex with lumazine synthase and riboflavin synthase activity. This complex accounts for 12–40% of the total riboflavin synthase activity in different members of the Bacillaceae. This enzyme complex has been designated “heavy riboflavin synthase.” The protein consists of 60 β subunits (lumazine synthase) that form an icosahedral capsid containing 3 α subunits (riboflavin synthase). The structure of this complex is presented in the chapter.
Markus Fischer - One of the best experts on this subject based on the ideXlab platform.
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the lumazine synthase riboflavin synthase complex shapes and functions of a highly variable enzyme system
FEBS Journal, 2013Co-Authors: Rudolf Ladenstein, A. Bacher, Markus FischerAbstract:The xylene ring of riboflavin (vitamin B2) is assembled from two molecules of 3,4-dihydroxy-2-butanone 4-phosphate by a mechanistically complex process that is jointly catalyzed by lumazine synthase and riboflavin synthase. In Bacillaceae, these enzymes form a structurally unique complex comprising an icosahedral shell of 60 lumazine synthase subunits and a core of three riboflavin synthase subunits, whereas many other bacteria have empty lumazine synthase capsids, fungi, Archaea and some eubacteria have pentameric lumazine synthases, and the riboflavin synthases of Archaea are paralogs of lumazine synthase. The structures of the molecular ensembles have been studied in considerable detail by X-ray crystallography, X-ray small-angle scattering and electron microscopy. However, certain mechanistic aspects remain unknown. Surprisingly, the quaternary structure of the icosahedral β subunit capsids undergoes drastic changes, resulting in formation of large, quasi-spherical capsids; this process is modulated by sequence mutations. The occurrence of large shells consisting of 180 or more lumazine synthase subunits has recently generated interest for protein engineering topics, particularly the construction of encapsulation systems.
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Biosynthesis of riboflavin: lumazine synthase and riboflavin synthase.
Methods in Enzymology, 1997Co-Authors: A. Bacher, Sabine Eberhardt, Markus Fischer, Simone Mörtl, Klaus Kis, Karl Kugelbrey, Johannes Scheuring, Schott KAbstract:Publisher Summary This chapter discusses the biosynthesis of riboflavin. 6,7-Dimethyl-8-ribityllumazine is developed as the direct biosynthetic precursor of riboflavin. The lumazine derivative is converted to riboflavin by the enzyme riboflavin synthase. The reaction involves the transfer of a four-carbon unit between two identical substrate molecules in an unusual dismutation reaction. The lumazine is biosynthesized from 5-amino-6-ribitylamino-2,4 (1 H ,3 H )-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate by the enzyme lumazine synthase. The riboflavin synthases of Bacillus subtilis and Escherichia coli are homotrimeric molecules. Members of the Bacillaceae also form a large multimeric enzyme complex with lumazine synthase and riboflavin synthase activity. This complex accounts for 12–40% of the total riboflavin synthase activity in different members of the Bacillaceae. This enzyme complex has been designated “heavy riboflavin synthase.” The protein consists of 60 β subunits (lumazine synthase) that form an icosahedral capsid containing 3 α subunits (riboflavin synthase). The structure of this complex is presented in the chapter.
Jung-hoon Yoon - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic analysis of the genus thermoactinomyces based on 16s rdna sequences
International Journal of Systematic and Evolutionary Microbiology, 2000Co-Authors: Jung-hoon Yoon, Yong-ha ParkAbstract:The almost complete 16S rDNA sequences of the type strains of eight validly described species and two invalid species of the genus Thermoactinomyces were determined and phylogenetically analysed. The validly described Thermoactinomyces species formed phylogenetic lineages related to the family Bacillaceae, as shown previously. However, the available strains of 'Thermoactinomyces glaucus' and 'Thermoactinomyces monosporus' exhibited their closest phylogenetic affinities not to the genus Thermoactinomyces but to the genus Saccharomonospora. Some Thermoactinomyces species were shown to be closely related from 16S rDNA sequence analysis. Particularly, Thermoactinomyces vulgaris KCTC 9076T and Thermoactinomyces candidus KCTC 9557T had the same 16S rDNA sequences and Thermoactinomyces thalpophilus KCTC 9789T and Thermoactinomyces sacchari KCTC 9790T showed 16S rDNA similarity value of almost 100%. From phylogenetic analysis based on 16S rDNA sequences, it is suggested that the genus Thermoactinomyces should be taxonomically re-evaluated using other useful taxonomic markers.
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Phylogenetic analysis of the genus Thermoactinomyces based on 16S rDNA sequences
Society for General Microbiology, 2000Co-Authors: Jung-hoon Yoon, Yong-ha ParkAbstract:The almost complete 16S rDNA sequences of the type strains of eight validly described species and two invalid species of the genus Thermoactinomyces were determined and phylogenetically analysed. The validly described Thermoactinomyces species formed phylogenetic lineages related to the family Bacillaceae, as shown previously. However, the available strains of 'Thermoactinomyces glaucus' and 'Thermoactinomyces monosporus' exhibited their closest phylogenetic affinities not to the genus Thermoactinomyces but to the genus Saccharomonospora. Some Thermoactinomyces species were shown to be closely related from 16S rDNA sequence analysis. Particularly, Thermoactinomyces vulgaris KCTC 9076(T) and Thermoactinomyces candidus KCTC 9557(T) had the same 16S rDNA sequences and Thermoactinomyces thalpophilus KCTC 9789(T) and Thermoactinomyces sacchari KCTC 9790(T) showed 16S rDNA similarity value of almost 100%. From phylogenetic analysis based on 16S rDNA sequences, it is suggested that the genus Thermoactinomyces should be taxonomically re-evaluated using other useful taxonomic markers.ope
