Crystal structure of the condensation domain from lovastatin polyketide synthase

The highly reducing iterative polyketide synthases responsible for lovastatin biosynthesis contains a section homologous to condensation(CON)domain observed in nonribosomal peptide synthetases(NRPSs).In the present study,we expressed the isolated lovastatin CON domain and solved the crystal structure to 1.79 A resolution.The overall structure shows similarity to canonical condensation domains of NRPSs,containing the N-terminal and C-terminal subdomains that resemble enzymes of chloramphenicol acetyltransferase family,whereas distinct structural features are observed at the active site.The acceptor entry of the substrate channel is blocked by a flexible loop,thereby preventing the loading of substrate for a new round of chain elongation.The mutation of conserved catalytic motif located at the midpoint of substrate channel agrees with the incapability of CON to catalyzed amide-bond formation.The structure helps to understand the function of CON in lovastatin biosynthesis.

Pd-Catalyzed Synthesis of a-Awl Vinylphosphonates via Suzuki Arylation of a-Phosphonovinyl Nonaflates

The first palladium-catalyzed method for the arylation of α-phosphonovinyl nonaflates is described. Using a catalyst comprised of Pd（OAc）2 and SPhos, terminal and internal α-aryl vinylphosphonates could be efficiently ac- cessed under mild conditions. The reaction features a broad coupling partner scope and tolerates many functional groups.