Proteomic analysis of curdlan-producing Agrobacterium sp． ATCC 31749 in response to dissolved oxygen

Abstract:

Abstract:［Objective］Curdlan is produced by Agrobacterium sp．ATCC 31749 under nitrogen limiting condition．The biosynthesis of crudlan is a typical aerobic bioprocess，and the production of curdlan would be severely restricted under micro-aerobic and anoxic conditions．Proteomic analysis of Agrobacterium sp． was conducted to investigate the effect of dissolved oxygen on the crucial enzymes involved in curdlan biosynthesis.［Methods］Two-dimensional gel electrophoresis was performed to separate and visualize the differential expression of the intracellular proteins extracted from Agrobacterium sp．ATCC 31749 cultured under various dissolved oxygen levels (75%，50%，25% and 5%). In addition，a comparative proteomic analysis of the intracellular proteins expression level under various dissolved oxygen levels was done． Significant differently expressed proteins were identified by MALDI-TOF/TOF.［Results］Finally，we identified 15 differently expressed proteins involved in polysaccharide synthesis，fatty acid synthesis，amino acid synthesis pathway．Among these proteins，phosphoglucomutase and orotidine 5-phosphate decarboxylase were the key metabolic enzymes directing curdlan biosynthesis.［Conclusion］Oxygen could affect the expression of the proteins taking charge of curdlan synthesis significantly.