Lsc? and lsc?, two novel levansucrases of Pseudomonas syringae pv. actinidiae biovar 3, the causal agent of bacterial canker of kiwifruit, show different enzymatic properties

Bacterial canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) biovar 3 involved all global interest since 2008. We have found that in Psa3 genome, similarly to other P. syringae, there are three putative genes, lsc?, lsc? and lsc?, coding for levansucrases. These enzymes, breaking the sucrose moiety releasing glucose can synthetize fructose polymer levan, a hexopolysaccharide is well known be part of survival strategies many different bacteria. Considering lsc? non-coding because premature stop codon, present work we cloned expressed two putatively functional levansucrases Psa3, E. coli characterized their biochemical properties such as optimum pH, temperature ionic strength. Interestingly, completely behaviour both splitting activity levan synthesis between proteins; lsc? polymerizes quickly at pH 5.0 while has great hydrolysis 7.0. Moreover, demonstrated least vitro conditions, they differentially suggesting distinct roles physiology bacterium.