Comparative proteome analysis of the outer membrane proteins of in vitro-induced multi-drug resistant Neisseria gonorrhoeae

Abstract

Antimicrobial-resistant gonococcus has been a major problem in sexually transmitted disease control . Outer membrane proteins (OMPs) of Neisseria gonorrhoeae were suggested to have influence on its resistance to antibiotics. So, in this work, we provide a proteomic analysis tool for examining the OMPs of N. gonorrhoeae and also provide a comparative analysis of the OMPs between the susceptible parent strain (92WT) and the resistance-induced isogenic mutant (92mu13) to determine the OMPs responsible for resistance. The 2-D gel spots of 92mu13 differed from 92WT particularly in porin, pilus secretion protein (PilQ) and enzymes. PilQ expression in 92mu13 was considerably reduced by abrupt termination at nucleotide 2,112. This made it difficult to form a high molecular mass (HMM) pore at the outer membrane; it is suspected that reduction of PilQ serves a role in antibiotic resistance in N. gonorrhoeae. The amount of porin was not changed but its isoelectric point (pI) shifted to a basic region, which is caused by the alteration of an amino acid of porin and it is suggested to relate to the development of antimicrobial resistance . Differential regulation of the enzymes involved in metabolism was found in 92mu13, believed to represent an adaptation of N. gonorrhoeae to the antibiotic environment.