[Study on the membrane proteins of Alkalimonas amylolytica N10 expressed at different pH environment]

The research on the membrane proteins expressed in alkaliphiles at different pH media will be benefit to understand the molecular mechanisms how they survive from such harsh alkaline environment. A preliminary investigation to the differential membrane proteomes from Alkalimonas amylolytica N10 (N10), a novel alkaliphilic bacterium, is reported herein. Upon the growth curves of N10 at different pH environment, three pH media, 8.4, 9.4 and 10.4, respectively, were employed to culture N10 followed by membrane preparation using ultracentrifuge and membrane proteins separation by 8% - 20% gradient SDS-PAGE. With carefully image analysis and statistical calculation, 7 stained bands were confirmed the alterations of relative optimal intensities corresponding with pH environment. Furthermore these bands were digested in-gel by trypsin and delivered to LC-MS/MS for protein identification. Twelve proteins were verified, of which four were reported involvement of the regulation of pH homeostasis in cytoplasm of alkaliphiles, and the others were originally found their protein expression responding to the environment with different pH values.