Structural and mechanistic investigation of the Cytochrome P450 enzymes in vancomycin biosynthesis: potential biocatalysts for the development of new antibiotics

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Antibiotics of the vancomycin family are glycopeptides with activity against Gram-positive bacteria, and are used as a last resort in the treatment of certain bacterial infections. They work by forming a complex with a cell-wall precursor, thus inhibiting bacterial cell wall biosynthesis. Their use is however restricted by the increasing problem of resistance: bacterial strains arise in which the precursor is modified and no longer tightly binds to vancomycin. It would be of great medical significance if new vancomycin analogues could be produced at short notice. This is hindered by the complexity of the chemical synthesis of vancomycin, in particular the phenolic crosslinking reactions which, in vivo, are performed by Cytochrome P450 (Oxy) enzymes. The mechanisms of action of the Oxy enzymes are of exceptional scientific interest in their own right, and will be studied in detail in this project using a combination of structural and biochemical approaches. The results from these experiments will answer central questions concerning substrate recognition and oxidation. They will also provide the basis for an alternative and rapid synthesis of vancomycin analogues, using synthetic peptides as the starting point but Oxy enzymes for the crucial final crosslinking reactions. A possible extension of this work will be to re-engineer elements of the vancomycin biosynthetic gene cluster to allow the entire synthesis of vancomycin analogues to be performed in suitable organisms in vivo.