Identification and in silico characterization of transcription termination/antitermination protein NusA of Mycobacterium fortuitum

Emerging infections due to pathogenic NTM Mycobacterium fortuitum highlights its virulence capability and importance in medical research. Considering the importance of membrane proteins in virulence, present study aims at in-silico characterization of membrane protein-encoding genes identified using transposon mutagenesis. A library of 450 mutants was constructed, of which mutant MT723 was shortlisted based on high alkaline phosphatase (reporter) activity. Transposon inserted segment of MT723 was cloned in pUC19 vector and sequenced. DNA sequence homology studies identified putative 'transcription termination/antitermination protein NusA' of M. fortuitum(MfNusA) to be mutated. Evolutionary analysis of MfNusA amino-acid sequence showed 45 % residues to be conserved. Using in-silico approach, NusA protein showed functional interactions with proteins required for transcription and translation. Literature survey of interacting proteins of NusA revealed their role in virulence, and hence, in-silico MfNusA structure was predicted, which would further help in determining functional aspects of the protein as an important virulence factor.