Download MendeleyStructure and Mechanism of the trans-Acting Acyltransferase from the Disorazole Synthase.
Wong, F.T., Jin, X., Mathews, I.I., Cane, D.E., Khosla, C.(2011) Biochemistry 50: 6539-6548
- PubMed: 21707057
- DOI: https://doi.org/10.1021/bi200632j
- Primary Citation of Related Structures:
3RGI, 3SBM - PubMed Abstract:
The 1.51 Å resolution X-ray crystal structure of the trans-acyltransferase (AT) from the "AT-less" disorazole synthase (DSZS) and that of its acetate complex at 1.35 Å resolution are reported. Separately, comprehensive alanine-scanning mutagenesis of one of its acyl carrier protein substrates (ACP1 from DSZS) led to the identification of a conserved Asp45 residue on the ACP, which contributes to the substrate specificity of this unusual enzyme. Together, these experimental findings were used to derive a model for the selective association of the DSZS AT and its ACP substrate. With a goal of structurally characterizing the AT-ACP interface, a strategy was developed for covalently cross-linking the active site Ser → Cys mutant of the DSZS AT to its ACP substrate and for purifying the resulting AT-ACP complex to homogeneity. The S86C DSZS AT mutant was found to be functional, albeit with a transacylation efficiency 200-fold lower than that of its wild-type counterpart. Our findings provide new insights as well as new opportunities for high-resolution analysis of an important protein-protein interface in polyketide synthases.
Organizational Affiliation:
Department of Chemical Engineering, Department of Chemistry, and §Department of Biochemistry, Stanford University , Stanford, California 94305, United States.
