Journal:JBIC:1
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| - | Adenylate kinases (AK) from Gram-negative bacteria are generally devoid of metal ions in their LID domain. However, <scene name='Journal:JBIC:1/Metal_bound/ | + | Adenylate kinases (AK) from Gram-negative bacteria are generally devoid of metal ions in their LID domain. However, <scene name='Journal:JBIC:1/Metal_bound/3'>three metal ions</scene>, 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 ; (<scene name='Journal:JBIC:1/Zinc_bound/2'>Zn2+, Zn-AK</scene>; <scene name='Journal:JBIC:1/Cobalt_bound/5'>Co2+, Co-AK</scene> and <scene name='Journal:JBIC:1/Fe_bound/7'>Fe2+, Fe-AK</scene>) bound in its LID domain have been determined by X-ray crystallography. <scene name='Journal:JBIC:1/Super/4'>All three crystal structures are very similar </scene>to each other with the same LID domain topology, the only change being the presence of the different metal atoms. |
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The structures of Zn- , Co- and Fe-AK contain the <scene name='Journal:JBIC:1/Lid_domain/3'>characteristic LID domain (residues 125-163)</scene> and <scene name='Journal:JBIC:1/Core_domain/1'>Core (residues 1-124 and 164-223) domains</scene>, which also include the AMP binding region. The LID domain harbors the Cys129-X5-His135-X15-Cys151-X2-Cys154- motif, 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 connected to the LID by residues 116-123 and 165-173. This Core domain mainly consists of a five stranded beta sheet surrounded by 5 helices that keep the integrity of the tertiary structure of the enzyme. A Walker motif 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. | The structures of Zn- , Co- and Fe-AK contain the <scene name='Journal:JBIC:1/Lid_domain/3'>characteristic LID domain (residues 125-163)</scene> and <scene name='Journal:JBIC:1/Core_domain/1'>Core (residues 1-124 and 164-223) domains</scene>, which also include the AMP binding region. The LID domain harbors the Cys129-X5-His135-X15-Cys151-X2-Cys154- motif, 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 connected to the LID by residues 116-123 and 165-173. This Core domain mainly consists of a five stranded beta sheet surrounded by 5 helices that keep the integrity of the tertiary structure of the enzyme. A Walker motif 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. | ||
Revision as of 10:34, 23 August 2010
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Crystal structure of the zinc, cobalt and iron containing adenylate kinase from Desulfovibrio gigas: a novel metal containing adenylate kinase from Gram-negative bacteria
By Dr. Mukhopadhyay & Abhik Mukhopadhyay
Journal of Biological Inorganic Chemistry
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 ; (; and ) 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 Cys129-X5-His135-X15-Cys151-X2-Cys154- motif, 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 connected to the LID by residues 116-123 and 165-173. This Core domain mainly consists of a five stranded beta sheet surrounded by 5 helices that keep the integrity of the tertiary structure of the enzyme. A Walker motif 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.
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