A Polyketide Synthase Acyltransferase Domain Structure Suggests a Recognition Mechanism for Its Hydroxymalonyl-Acyl Carrier Protein Substrate
Figure 6
Proposed movement of the substrate pocket lid induced by ZmaD binding.
(A) Based on the crystal structure of ZmaA-AT, the substrate pocket lid (blue) is shown in the closed position, restricting the entry of the extender unit, in the absence of substrate carrier protein. (B) Model structure of ZmaA-AT bound to substrate carrier protein, ZmaD (blue spheroid). The binding of the substrate carrier protein to the RXR motif (M286-C-M288 in ZmaA-AT; gray sticks) in the small subdomain of ZmaA-AT is proposed to cause the formation of the β-strand (red), resulting in the opening of the substrate pocket lid (blue).