Probing the role of the bridging C509 between the [Fe4S4] cubane and the [Ni(p)Ni(d)] centre in the A-cluster of acetyl-coenzyme A synthase.

The A-cluster of acetyl-coenzyme A synthase consists of an [Fe(4)S(4)] cubane bridged to a [Ni(p)Ni(d)] centre via C509 cysteinate. The bridging cysteinate, which could be substituted by histidine imidazole, mediates "communication" between the [Fe(4)S(4)] cubane and the [Ni(p)Ni(d)] centre during the synthesis of acetyl-coenzyme A.