A new type of metal-binding site in cobalt- and zinc- containing adenylate kinases isolated from sulfate-reducers Desulfovibrio gigas and Desulfovibrio desulfuricans ATCC 27774
| Autor: | Ingrid J. Pickering, Graham N. George, Pedro Tavares, Olga Yu. Gavel, Juan J. Calvete, Valery L. Shnyrov, Sergey A. Bursakov, José Trincão, Isabel Moura, Jorge Lampreia, Alice S. Pereira, José J. G. Moura, Giulia Di Rocco, Carlos D. Brondino |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
inorganic chemicals
Stereochemistry Molecular Sequence Data chemistry.chemical_element Adenylate kinase Metal Binding Site Zinc Biochemistry Inorganic Chemistry Absorptiometry Photon Apoenzymes Desulfovibrio gigas Amino Acid Sequence Desulfovibrio desulfuricans Histidine Binding Sites biology Adenylate Kinase Osmolar Concentration Electron Spin Resonance Spectroscopy Cobalt biology.organism_classification Desulfovibrio Protein Structure Tertiary Molecular Weight Pyrimidines chemistry Spectrophotometry Ultraviolet Sulfate-reducing bacteria Sequence Alignment Cysteine |
| Popis: | Adenylate kinase (AK) mediates the reversible transfer of phosphate groups between the adenylate nucleotides and contributes to the maintenance of their constant cellular level, necessary for energy metabolism and nucleic acid synthesis. The AK were purified from crude extracts of two sulfate-reducing bacteria (SRB), Desulfovibrio ( D. ) gigas NCIB 9332 and Desulfovibrio desulfuricans ATCC 27774, and biochemically and spectroscopically characterised in the native and fully cobalt- or zinc-substituted forms. These are the first reported adenylate kinases that bind either zinc or cobalt and are related to the subgroup of metal-containing AK found, in most cases, in Gram-positive bacteria. The electronic absorption spectrum is consistent with tetrahedral coordinated cobalt, predominantly via sulfur ligands, and is supported by EPR. The involvement of three cysteines in cobalt or zinc coordination was confirmed by chemical methods. Extended X-ray absorption fine structure (EXAFS) indicate that cobalt or zinc are bound by three cysteine residues and one histidine in the metal-binding site of the “LID” domain. The sequence 129 Cys-X 5 -His-X 15 -Cys-X 2 -Cys of the AK from D. gigas is involved in metal coordination and represents a new type of binding motif that differs from other known zinc-binding sites of AK. Cobalt and zinc play a structural role in stabilizing the LID domain. |
| Databáze: | OpenAIRE |
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