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

Published Date
Journal of Inorganic Biochemistry
May 2008, Vol.102(5):1380–1395, doi:10.1016/j.jinorgbio.2008.01.023
13th International Conference on Biological Inorganic Chemistry

Author 

• Olga Yu. Gavel ^a
• Sergey A. Bursakov ^a,,
• Giulia Di Rocco ^a
• José Trincão ^a
• Ingrid J. Pickering^b
• Graham N. George ^b
• Juan J. Calvete ^c
• Valery L. Shnyrov ^d
• Carlos D. Brondino ^a,1
• Alice S. Pereira ^a
• Jorge Lampreia ^a
• Pedro Tavares ^a
• José J.G. Moura ^a
• Isabel Moura ^a,,

• aREQUIMTE, Departamento de Química, Centro de Química Fina e Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
• bUniversity of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2
• cInstituto de Biomedicina, C.S.I.C., Valencia E-46010, Spain
• dDepartamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de Salamanca, pza Doctores de la Reina, s/n, 37007 Salamanca, Spain

Received 13 September 2007. Revised 13 January 2008. Accepted 18 January 2008. Available online 1 February 2008. 

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

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 Table 1

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 Table 2

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  Corresponding authors. Tel.: +351 21 294 83 81; fax: +351 21 294 85 50 (S.A. Bursakov, I. Moura).

Copyright © 2008 Elsevier Inc. All rights reserved.

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