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Histidine

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Histidine - Free Register to Access Experts & Abstracts

Barry P. Rosen - One of the best experts on this subject based on the ideXlab platform.

  • Original Research Report: Structure-Function Analysis of the ArsA ATPase: Contribution of Histidine Residues
    Journal of Bioenergetics and Biomembranes, 2001
    Co-Authors: Hiranmoy Bhattacharjee, Barry P. Rosen
    Abstract:

    The ArsA ATPase is the catalytic subunit of the ArsAB oxyanion pump in Escherichia coli that is responsible for extruding arsenite or antimonite from inside the cell, thereby conferring resistance. Either antimonite or arsenite stimulates ArsA ATPase activity. In this study, the role of Histidine residues in ArsA activity was investigated. Treatment of ArsA with diethyl pyrocarbonate (DEPC) resulted in complete loss of catalytic activity. The inactivation could be reversed upon subsequent incubation with hydroxylamine, suggesting specific modification of Histidine residues. ATP and oxyanions afforded significant protection against DEPC inactivation, indicating that the Histidines are located at the active site. ArsA has 13 Histidine residues located at position 138, 148, 219, 327, 359, 368, 388, 397, 453, 465, 477, 520, and 558. Each Histidine was individually altered to alanine by site-directed mutagenesis. Cells expressing the altered ArsA proteins were resistant to both arsenite and antimonite. The results indicate that no single Histidine residue plays a direct role in catalysis, and the inhibition by DEPC may be caused by steric hindrance from the carbethoxy group.

  • Structure-function analysis of the ArsA ATPase: contribution of Histidine residues.
    Journal of Bioenergetics and Biomembranes, 2001
    Co-Authors: Hiranmoy Bhattacharjee, Barry P. Rosen
    Abstract:

    The ArsA ATPase is the catalytic subunit of the ArsAB oxyanion pump in Escherichia coli that is responsible for extruding arsenite or antimonite from inside the cell, thereby conferring resistance. Either antimonite or arsenite stimulates ArsA ATPase activity. In this study, the role of Histidine residues in ArsA activity was investigated. Treatment of ArsA with diethyl pyrocarbonate (DEPC) resulted in complete loss of catalytic activity. The inactivation could be reversed upon subsequent incubation with hydroxylamine, suggesting specific modification of Histidine residues. ATP and oxyanions afforded significant protection against DEPC inactivation, indicating that the Histidines are located at the active site. ArsA has 13 Histidine residues located at position 138, 148, 219, 327, 359, 368, 388, 397, 453, 465, 477, 520, and 558. Each Histidine was individually altered to alanine by site-directed mutagenesis. Cells expressing the altered ArsA proteins were resistant to both arsenite and antimonite. The results indicate that no single Histidine residue plays a direct role in catalysis, and the inhibition by DEPC may be caused by steric hindrance from the carbethoxy group.

Hiranmoy Bhattacharjee - One of the best experts on this subject based on the ideXlab platform.

  • Original Research Report: Structure-Function Analysis of the ArsA ATPase: Contribution of Histidine Residues
    Journal of Bioenergetics and Biomembranes, 2001
    Co-Authors: Hiranmoy Bhattacharjee, Barry P. Rosen
    Abstract:

    The ArsA ATPase is the catalytic subunit of the ArsAB oxyanion pump in Escherichia coli that is responsible for extruding arsenite or antimonite from inside the cell, thereby conferring resistance. Either antimonite or arsenite stimulates ArsA ATPase activity. In this study, the role of Histidine residues in ArsA activity was investigated. Treatment of ArsA with diethyl pyrocarbonate (DEPC) resulted in complete loss of catalytic activity. The inactivation could be reversed upon subsequent incubation with hydroxylamine, suggesting specific modification of Histidine residues. ATP and oxyanions afforded significant protection against DEPC inactivation, indicating that the Histidines are located at the active site. ArsA has 13 Histidine residues located at position 138, 148, 219, 327, 359, 368, 388, 397, 453, 465, 477, 520, and 558. Each Histidine was individually altered to alanine by site-directed mutagenesis. Cells expressing the altered ArsA proteins were resistant to both arsenite and antimonite. The results indicate that no single Histidine residue plays a direct role in catalysis, and the inhibition by DEPC may be caused by steric hindrance from the carbethoxy group.

  • Structure-function analysis of the ArsA ATPase: contribution of Histidine residues.
    Journal of Bioenergetics and Biomembranes, 2001
    Co-Authors: Hiranmoy Bhattacharjee, Barry P. Rosen
    Abstract:

    The ArsA ATPase is the catalytic subunit of the ArsAB oxyanion pump in Escherichia coli that is responsible for extruding arsenite or antimonite from inside the cell, thereby conferring resistance. Either antimonite or arsenite stimulates ArsA ATPase activity. In this study, the role of Histidine residues in ArsA activity was investigated. Treatment of ArsA with diethyl pyrocarbonate (DEPC) resulted in complete loss of catalytic activity. The inactivation could be reversed upon subsequent incubation with hydroxylamine, suggesting specific modification of Histidine residues. ATP and oxyanions afforded significant protection against DEPC inactivation, indicating that the Histidines are located at the active site. ArsA has 13 Histidine residues located at position 138, 148, 219, 327, 359, 368, 388, 397, 453, 465, 477, 520, and 558. Each Histidine was individually altered to alanine by site-directed mutagenesis. Cells expressing the altered ArsA proteins were resistant to both arsenite and antimonite. The results indicate that no single Histidine residue plays a direct role in catalysis, and the inhibition by DEPC may be caused by steric hindrance from the carbethoxy group.

John M. Mccoy - One of the best experts on this subject based on the ideXlab platform.

  • Histidine Patch Thioredoxins MUTANT FORMS OF THIOREDOXIN WITH METAL CHELATING AFFINITY THAT PROVIDE FOR CONVENIENT PURIFICATIONS OF THIOREDOXIN FUSION PROTEINS
    The Journal of biological chemistry, 1996
    Co-Authors: Elizabeth Diblasio-smith, Kathleen L. Grant, Nicholas W. Warne, Edward R. Lavallie, Lisa A. Collins-racie, Maximillian Follettie, Mark J. Williamson, John M. Mccoy
    Abstract:

    Abstract A cluster of surface amino acid residues on Escherichia coli thioredoxin were systematically mutated in order to provide the molecule with an ability to chelate metal ions. The combined effect of two Histidine mutants, E30H and Q62H, gave thioredoxin the capacity to bind to nickel ions immobilized on iminodiacetic acid- and nitrilotriacetic acid-Sepharose resins. Even though these two Histidines were more than 30 residues apart in thioredoxin's primary sequence, they were found to satisfy the geometric constraints for metal ion coordination as a result of the thioredoxin tertiary fold. A third Histidine mutation, S1H, provided additional metal ion chelation affinity, but the native Histidine at position 6 of thioredoxin was found not to participate in binding. All of the Histidine mutants exhibited decreased thermal stability as compared with wild-type thioredoxin; however, the introduction of an additional mutation, D26A, increased their melting temperatures beyond that of wild-type thioredoxin. The metal chelating abilities of these Histidine mutants of thioredoxin were successfully utilized for convenient purifications of human interleukin-8 and −11 expressed in E. coli as soluble thioredoxin fusion proteins.

Laura M. Hunsicker-wang - One of the best experts on this subject based on the ideXlab platform.

  • Reactive sites and course of reduction in the Rieske protein
    JBIC Journal of Biological Inorganic Chemistry, 2017
    Co-Authors: Si Ying Li, Paul H. Oyala, R. David Britt, Susan T. Weintraub, Laura M. Hunsicker-wang
    Abstract:

    Rieske proteins play an essential role in electron transfer in the bc _1 complex. Rieske proteins contain a [2Fe–2S] cluster with one iron ligated by two Histidines and the other iron ligated by two cysteines. All Rieske proteins have pH-dependent reduction potentials with the Histidines ligating the cluster deprotonating in response to increases in pH. The addition of diethylpyrocarbonate (DEPC) modifies deprotonated Histidines. The previous studies on the isolated Thermus thermophilus Rieske protein have used large excesses of DEPC, and this study examines what amino acids become modified under different molar equivalents of DEPC to protein. Increasing amounts of DEPC result in more modification, and higher pH values result in faster reaction. Upon modification, the protein also becomes reduced and ~6 equivalents of DEPC are needed for 50% of the reduction to occur. Which amino acids are modified first also points to the most reactive species on the protein. Mass spectrometry analysis shows that lysine 68 is the most reactive amino acid, followed by the ligating Histidine 154 and two other surfaces lysines, 76 and 43. The modification of the ligating Histidine at low numbers of DEPC equivalents and correlation with a similar number of equivalents needed to reduce the protein shows that this Histidine can interact with neighboring groups, and these results can be extended to the protein within the bc _ 1 complex, where interaction with neighboring residues or molecules may allow reduction to occur. These results may shed light on how Rieske transfers electrons and protons in the bc _ 1 complex.

  • The reduction rates of DEPC-modified mutant Thermus thermophilus Rieske proteins differ when there is a negative charge proximal to the cluster
    JBIC Journal of Biological Inorganic Chemistry, 2014
    Co-Authors: Nicholas E. Karagas, Christie N. Jones, Deborah J. Osborn, Anika L. Dzierlenga, Paul Oyala, Mary E. Konkle, Emily M. Whitney, R. David Britt, Laura M. Hunsicker-wang
    Abstract:

    Rieske and Rieske-type proteins are electron transport proteins involved in key biological processes such as respiration, photosynthesis, and detoxification. They have a [2Fe–2S] cluster ligated by two cysteines and two Histidines. A series of mutations, L135E, L135R, L135A, and Y158F, of the Rieske protein from Thermus thermophilus has been produced which probe the effects of the neighboring residues, in the second sphere, on the dynamics of cluster reduction and the reactivity of the ligating Histidines. These properties were probed using titrations and modifications with diethyl pyrocarbonate (DEPC) at various pH values monitored using UV–Visible and circular dichroism spectrophotometry. These results, along with results from EPR studies, provide information on ligating Histidine modification and rate of reduction of each of the mutant proteins. L135R, L135A, and Y158F react with DEPC similarly to wild type, resulting in modified protein with a reduced [2Fe–2S] cluster in 15 h under the same conditions. Thus, the negative charge slows down the rate of reduction and provides an explanation as to why negatively charged residues are rarely, if ever, found in the equivalent position of other Rieske and Rieske-type proteins.

Bernard L. Trumpower - One of the best experts on this subject based on the ideXlab platform.

  • Mutational analysis of the mitochondrial Rieske iron-sulfur protein of Saccharomyces cerevisiae. III. Import, protease processing, and assembly into the cytochrome bc1 complex of iron-sulfur protein lacking the iron-sulfur cluster.
    The Journal of biological chemistry, 1991
    Co-Authors: Laurie A. Graham, Bernard L. Trumpower
    Abstract:

    Abstract We have used site-directed mutagenesis of the Saccharomyces cerevisiae Rieske iron-sulfur protein gene (RIP 1) to convert cysteines 159, 164, 178, and 180 to serines, and to convert Histidines 161 and 181 to arginines. These 4 cysteines and 2 Histidines are conserved in all Rieske proteins sequenced to date, and 4 of these 6 residues are thought to ligate the iron-sulfur cluster to the apoprotein. We have also converted Histidine 184 to arginine. This Histidine is conserved only in respiring organisms. The site-directed mutations of the six fully conserved putative iron-sulfur cluster ligands result in an inactive iron-sulfur protein, lacking iron-sulfur cluster, and failure of the yeast to grow on nonfermentable carbon sources. In contrast, when Histidine 184 is replaced by arginine, the iron-sulfur cluster is assembled properly and the yeast grow on nonfermentable carbon sources. The site-directed mutations of the 6 fully conserved residues do not prevent post-translational import of iron-sulfur protein precursor into mitochondria, nor do the mutations prevent processing of iron-sulfur protein precursor to mature size protein by mitochondrial proteases. Optical spectra of mitochondria from the six mutants indicate that cytochrome b is normal, in contrast to the deranged spectrum of cytochrome b which results when the iron-sulfur protein gene is deleted. In addition, mature size iron-sulfur apoprotein is associated with cytochrome bc1 complex purified from a site-directed mutant in which iron-sulfur cluster is not inserted. These results indicate that mature size iron-sulfur apoprotein, lacking iron-sulfur cluster, is inserted into the cytochrome bc1 complex, where it interacts with and preserves the optical properties of cytochrome b. Insertion of the iron-sulfur cluster is not an obligatory prerequisite to processing of the protein to its final size. Either the processing protease cannot distinguish between iron-sulfur protein with or without the iron-sulfur cluster, or insertion of the iron-sulfur cluster occurs after the protein is processed to its mature size, possibly after it is assembled in the cytochrome bc1 complex.