Novel Domain Arrangement in the Crystal Structure of a Truncated Acetyl-CoA Synthase from Moorella thermoacetica,

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• 作者：Anne Volbeda ; Claudine Darnault ; Xiangshi Tan ; Paul A. Lindahl ; Juan C. Fontecilla-Camps
• 刊名：Biochemistry
• 出版年：2009
• 出版时间：August 25, 2009
• 年：2009
• 卷：48
• 期：33
• 页码：7916-7926
• 全文大小：1406K
• 年卷期：v.48,no.33(August 25, 2009)
• ISSN：1520-4995

文摘

Ni-dependent acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH) constitute the central enzyme complex of the Wood−Ljungdahl pathway of acetyl-CoA formation. The crystal structure of a recombinant bacterial ACS lacking the N-terminal domain that interacts with CODH shows a large reorganization of the remaining two globular domains, producing a narrow cleft of suitable size, shape, and nature to bind CoA. Sequence comparisons with homologous archaeal enzymes that naturally lack the N-terminal domain show that many amino acids lining this cleft are conserved. Besides the typical [4Fe-4S] center, the A-cluster contains only one proximal metal ion that, according to anomalous scattering data, is most likely Cu or Zn. Incorporation of a functional Ni₂Fe₄S₄ A-cluster would require only minor structural rearrangements. Using available structures, a plausible model of the interaction between CODH and the smaller ACS in archaeal multienzyme complexes is presented, along with a discussion of evolutionary relationships of the archaeal and bacterial enzymes.