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Johnson EA, Rice S, Preimesberger MR, Nye DB, Gilevicius L, Wenke BB, Brown JM, Witman GB, Lecomte JTJ. Characterization of THB1, a Chlamydomonas reinhardtii truncated hemoglobin: linkage to nitrogen metabolism and identification of lysine as the distal heme ligand. Biochemistry 2014; 53:4573-89. [PMID: 24964018 PMCID: PMC4108185 DOI: 10.1021/bi5005206] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/23/2014] [Indexed: 12/21/2022]
Abstract
The nuclear genome of the model organism Chlamydomonas reinhardtii contains genes for a dozen hemoglobins of the truncated lineage. Of those, THB1 is known to be expressed, but the product and its function have not yet been characterized. We present mutagenesis, optical, and nuclear magnetic resonance data for the recombinant protein and show that at pH near neutral in the absence of added ligand, THB1 coordinates the heme iron with the canonical proximal histidine and a distal lysine. In the cyanomet state, THB1 is structurally similar to other known truncated hemoglobins, particularly the heme domain of Chlamydomonas eugametos LI637, a light-induced chloroplastic hemoglobin. Recombinant THB1 is capable of binding nitric oxide (NO(•)) in either the ferric or ferrous state and has efficient NO(•) dioxygenase activity. By using different C. reinhardtii strains and growth conditions, we demonstrate that the expression of THB1 is under the control of the NIT2 regulatory gene and that the hemoglobin is linked to the nitrogen assimilation pathway.
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Affiliation(s)
- Eric A. Johnson
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Selena
L. Rice
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | - Dillon B. Nye
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Lukas Gilevicius
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Belinda B. Wenke
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jason M. Brown
- Department
of Cell and Developmental Biology, University
of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - George B. Witman
- Department
of Cell and Developmental Biology, University
of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - Juliette T. J. Lecomte
- Department
of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Badyal SK, Metcalfe CL, Basran J, Efimov I, Moody PCE, Raven EL. Iron Oxidation State Modulates Active Site Structure in a Heme Peroxidase,. Biochemistry 2008; 47:4403-9. [DOI: 10.1021/bi702337n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sandip K. Badyal
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, U.K., and Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, U.K
| | - Clive L. Metcalfe
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, U.K., and Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, U.K
| | - Jaswir Basran
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, U.K., and Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, U.K
| | - Igor Efimov
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, U.K., and Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, U.K
| | - Peter C. E. Moody
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, U.K., and Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, U.K
| | - Emma Lloyd Raven
- Department of Chemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 7RH, England, U.K., and Department of Biochemistry and Henry Wellcome Laboratories for Structural Biology, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, England, U.K
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Halder P, Trent JT, Hargrove MS. Influence of the protein matrix on intramolecular histidine ligation in ferric and ferrous hexacoordinate hemoglobins. Proteins 2007; 66:172-82. [PMID: 17044063 DOI: 10.1002/prot.21210] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Present in most organisms, hexacoordinate hemoglobins (hxHbs) are proteins that have evolved the capacity for reversible bis-histidyl heme coordination. The heme prosthetic group enables diverse protein functionality, such as electron transfer, redox reactions, ligand transport, and enzymatic catalysis. The reactivity of heme is greatly effected by the coordination and noncovalent chemical environment imposed by its connate protein. Of considerable interest is how the hxHb globin fold achieves reversible intramolecular coordination while still enabling high-affinity binding of oxygen, nitric oxide, and other small ligands. Here we explore this question by examining the role of the protein matrix on coordination behavior in a group of hxHbs from animals, plants, and bacteria, including human neuroglobin and cytoglobin, a nonsymbiotic hemoglobin from rice, and a truncated hemoglobin from the cyanobacterium Synechocystis. This is done with a set of experiments measuring the reduction potentials of each wild-type hxHb and its corresponding mutant protein where the reversibly bound histidine (the distal His) has been replaced with a noncoordinating side chain. These reduction potentials, coupled with studies of the mutant proteins saturated with exogenous imidazole, enable us to assess the effects of the protein matrices on histidine coordination. Our results show significant variation among the hxHbs, demonstrating flexibility in the globin moiety's ability to regulate reversible coordination. This regulation is particularly evident in the plant nonsymbiotic hemoglobins, where ferric state histidine coordination affinity is substantially lowered by the protein matrix.
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Affiliation(s)
- Puspita Halder
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA
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Weiland TR, Kundu S, Trent JT, Hoy JA, Hargrove MS. Bis-histidyl hexacoordination in hemoglobins facilitates heme reduction kinetics. J Am Chem Soc 2005; 126:11930-5. [PMID: 15382928 DOI: 10.1021/ja046990w] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hexacoordinate hemoglobins are a class of proteins that exhibit reversible bis-histidyl coordination of the heme iron while retaining the ability to bind exogenous ligands. One hypothesis for their physiological function is that they scavenge nitric oxide, a reaction that oxidizes the protein and requires reduction of the heme iron to continue. Reduction kinetics of hexacoordinate hemoglobins, including human neuroglobin and cytoglobin, and those from Synechocystis and rice, are compared to myoglobin, soybean leghemoglobin, and several relevant mutant proteins. In all cases, bis-histidyl coordination greatly increases the rate of reduction by sodium dithionite when compared to pentacoordinate hemoglobins. In myoglobin and leghemoglobin, reduction is limited by the rate constant for electron transfer, whereas in the hexacoordinate hemoglobins reduction is limited only by bimolecular binding of the reductant. These results can be explained by differences in the reorganization energy for reduction between hexacoordinate and pentacoordinate hemoglobins.
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Affiliation(s)
- Theodore R Weiland
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA
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