Influence of deletions in the apoemulsan gene cluster on A. venetianus RAG-1 polysaccharide biosynthesis.

Apoemulsan is a biopolymer with potent emulsification activity, produced by Acinetobacter venetianus RAG-1 (RAG-1). The wee gene cluster is responsible for apoemulsan biosynthesis. The analysis of (i) a putative polysaccharide copolymerase mutant (wzc), (ii) a putative polymerase mutant (wzy), and (iii) an apoemulsan-deficient variant (2) indicated that the wee gene cluster controls the synthesis of two polysaccharides: high molecular weight (HMW) and low molecular weight (LMW). LMW polysaccharide of wee origin was present in LPS isolated from RAG-1 cells, suggesting a link to the Lipid A-core of LPS molecules. SDSPAGE analysis indicated that apoemulsan is copurified with LPS polysaccharide, with implications in the emulsification activity of RAG-1 polymer.