Investigations of Orthosomycin Biosynthesis

Abstract

Orthosomycins are highly decorated oligosaccharides with potent activity against a variety of Gram-positive bacteria including methicillin-resistant staphylococci and vancomycin-resistant enterococci. The research in this dissertation focuses on a deeper understanding of orthosomycin biosynthesis towards the translational goal of developing an everninomicin with improved pharmacology activity. First, we developed methods for genetic manipulation of the everninomicin producing organism, Micromonospora carbonacea var aurantiaca, and for analysis of everninomicins and analogs. We then applied these methods to provide the first functional analysis of the everninomicin biosynthetic gene cluster in M. carbonacea var aurantiaca. We identified the role of three enzymes in the pathway and generated five new analogs. Toward a deeper understanding of orthosomycin biosynthesis, we provided the first evidence for the role of a conserved group of oxygenases in the formation of the orthoester linkages and methylenedioxy bridges of the orthosomycins. Together these results provide significant contributions to the understanding of orthosomycin biosynthesis. The ability to generate new everninomicin analogs via biosynthetic manipulations will prove critical in understanding their structure-activity relationship and developing an everninomicin with an improved pharmacological profile and potent activity against dangerous bacterial infections.