Journal:JBIC:1

Crystal structure of the zinc, cobalt and iron containing adenylate kinase from Desulfovibrio gigas: a novel metal containing adenylate kinase from Gram-negative bacteria

A. Mukhopadhyay, A.V. Kladova, S.A. Bursakov, O. Yu. Gavel, J.J. Calvete, V.L. Shnyrov, I. Moura, J.J.G. Moura, M.J. Romão, J. Trincão ^[1]

Molecular Tour
        Adenylate kinase (ATP:AMP phosphotransferase, EC 2.7.4.3; AK) is an essential catalyst for cellular growth and multiplication. AK belongs to a family of enzymes essential to life, and is highly abundant inside the cell. It is involved in the reversible transfer of the terminal phosphate group from Mg2+ATP to Mg2+AMP with high energy turnover: Mg2+ATP + AMP↔Mg2+ADP + ADP.

        Adenylate kinases (AK) from Gram-negative bacteria are generally devoid of metal ions in their LID domain. However, , zinc, cobalt and iron, have been found in AK from Gram-negative bacteria. Crystal structures of substrate-free AK from Desulfovibrio gigas with three different metal ions: (2xb4); (3l0s) and (3l0p) bound in its LID domain have been determined by X-ray crystallography. to each other with the same LID domain topology, the only change being the presence of the different metal atoms.

        The structures of Zn- , Co- and Fe-AK contain the and , which also include the AMP binding region. The LID domain harbors the , which is responsible for metal binding in a tetrahedral fashion. In the absence of any substrate, the LID domain of all holo forms of AK was present in a fully open conformational state. The Core domain is . This Core domain mainly consists of a that keep the integrity of the tertiary structure of the enzyme. A with conserved sequence; G-X-X-G-X-G-K is present in the N-terminal region. The structures presented herein further reinforce the notion that the metal ion is purely structural, contributing to the stability of the LID domain.