Adenylate kinase: Difference between revisions
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<StructureSection load="" size="350" color="" spin="on" Scene ="Journal:JBIC:1/Jbic1_opening/2" caption="(PDB code [[3l0p]]) Crystal structure of Fe (orange) bound adenylate kinase complex with glycerol from ''Desulfovibrio gigas''"> | |||
[[Adenylate kinase]] (ADK) is a | [[Adenylate kinase]] (ADK, EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.4.3 2.7.4.3]) is a [[Phosphotransferase]] which catalyzes the interconversion of ADP to ATP+AMP. ADK is important in cellular energy homeostasis. Dinucleotides polyphosphates like diadenosine pentaphosphate | ||
(AP5) inhibit ADK | (AP5) inhibit ADK. | ||
Adenylate kinase is an essential catalyst for cellular growth and multiplication. ADK 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. | |||
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Adenylate kinases (ADK) from Gram-negative bacteria are generally devoid of metal ions in their LID domain. However, <scene name='Journal:JBIC:1/Metal_bound/4'>three metal ions</scene>, zinc, cobalt and iron, have been found in ADK from Gram-negative bacteria. Crystal structures of substrate-free ADK from Desulfovibrio gigas with three different metal ions: <scene name='Journal:JBIC:1/Zinc_bound/3'>Zn2+, Zn-ADK</scene> ([[2xb4]]); <scene name='Journal:JBIC:1/Cobalt_bound/7'>Co2+, Co-ADK</scene> ([[3l0s]]) and <scene name='Journal:JBIC:1/Fe_bound/8'>Fe2+, Fe-ADK</scene> ([[3l0p]]) bound in its LID domain have been determined by X-ray crystallography. All three crystal structures are very similar 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-ADK contain the <scene name='Journal:JBIC:1/Lid_domain/5'>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 <scene name='Journal:JBIC:1/Metal_motif/1'>Cys129-X5-His135-X15-Cys151-X2-Cys154- motif</scene>, which is responsible for metal binding in a tetrahedral fashion. In the absence of any substrate, the LID domain of all holo forms of ADK was present in a fully open conformational state. The Core domain is <scene name='Journal:JBIC:1/Core_connection/3'>connected to the LID by residues 116-123 and 165-173</scene>. This Core domain mainly consists of a <scene name='Journal:JBIC:1/Core_helix/3'>five stranded beta sheet surrounded by 5 helices</scene> that keep the integrity of the tertiary structure of the enzyme. A <scene name='Journal:JBIC:1/Walker/4'>Walker motif</scene> with conserved sequence; <span style="color:#FF0000">G</span>-<span style="color:#FF8040">X</span>-<span style="color:#FFFF00">X</span>-<span style="color:#00FF00">G</span>-<span style="color:#0000FF">X</span>-<span style="color:#FF00FF">G</span>-<span style="color:#00FFFF">K</span> 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.<ref >DOI 10.1007/s00775-010-0700-8</ref> | |||
== 3D Structures of Adenylate kinase == | == 3D Structures of Adenylate kinase == | ||
[[Adenylate kinase 3D structures]] | |||
</StructureSection> | |||
==References== | |||
<references/> | |||
[[Category:Topic Page]] | [[Category:Topic Page]] | ||