Biosynthesis of the antibiotic Mupirocin by Pseudomonas fluorescens NCIMB 10586

Gurney, Rachel (2013). Biosynthesis of the antibiotic Mupirocin by Pseudomonas fluorescens NCIMB 10586. University of Birmingham. Ph.D.

Preview

Gurney13PhD.pdf
PDF - Accepted Version
Download (11MB)

Abstract

The mupirocin biosynthetic pathway belongs to the trans-AT group in which acyltransferase (AT) activity is provided by a separate polypeptide (MmpC) rather than in cis as found in the typical type I polyketide synthases. AT docking domains have been documented in trans-AT PKS clusters for ten years yet little functional evidence is available. The cluster shows many interesting features that must be understood to create novel products.

Specificity studies demonstrated that AT2 performs the typical AT function of loading malonyl-CoA to ACPs throughout the cluster. Mutagenesis studies demonstrated the importance of AT active site residues for protein structural integrity, acquisition and transfer of malonate and propose an alternate role for AT1 as a proofreading enzyme responsible for hydrolysing truncated intermediates from the pathway. Consequently an edit, reload, reduce model for MmpC is proposed. Mutagenesis of docking domains led to a halt in mupirocin production and suggested that docking domains are required for structural integrity of the Mmps or for guiding the ACPs into the correct position for interactions with their respective partners. Studies involving a mutated ACP3 protein confirmed the importance of Trp55, as demonstrated by structural changes and the inability of the protein to accept malonate from AT2.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):