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 |
| |
Authors: | Olga Yu Gavel Sergey A Bursakov Giulia Di Rocco Jos Trinco Ingrid J Pickering Graham N George Juan J Calvete Valery L Shnyrov Carlos D Brondino Alice S Pereira Jorge Lampreia Pedro Tavares Jos JG Moura Isabel Moura |
| |
Institution: | Olga Yu. Gavel, Sergey A. Bursakov, Giulia Di Rocco, José Trincão, Ingrid J. Pickering, Graham N. George, Juan J. Calvete, Valery L. Shnyrov, Carlos D. Brondino, Alice S. Pereira, Jorge Lampreia, Pedro Tavares, José J.G. Moura,Isabel Moura, |
| |
Abstract: | 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 129Cys-X5-His-X15-Cys-X2-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. |
| |
Keywords: | Adenylate kinase Cobalt Zinc Sulfate-reducing bacteria |
本文献已被 ScienceDirect 等数据库收录! |
|