In silico Functional Annotation and Characterization of Hypothetical Proteins from Serratia marcescens FGI94

Serratia marcescens, rod-shaped Gram-negative bacteria is classified as an opportunistic pathogen in the family Enterobacteriaceae. It causes a wide variety of infections in humans, including urinary, respiratory, ocular lens and ear infections, osteomyelitis, endocarditis, meningitis and septicemia. Unfortunately, over the past decade, antibiotic resistance has become a serious health care issue; the effective means to control and dissemination of S. marcescens resistance is the need of hour. The whole genome sequencing of S. marcescens FGI94 strain contains 4434 functional proteins, among which 690 (15.56%) proteins were classified under hypothetical. In the present study, we applied the power of various bioinformatics tools on the basis of protein family comparison, motifs, functional properties of amino acids and genome context to assign the possible functions for the HPs. The pseudo sequences (protein sequence that contain ≤100 amino acid residues) are eliminated from the study. Although we have successfully predicted the function for 483 proteins, we were able to infer the high level of confidence only for 108 proteins. The predicted HPs were classified into various classes such as enzymes, transporters, binding proteins, cell division, cell regulatory and other proteins. The outcome of the study could be helpful to understand the molecular mechanism in bacterial pathogenesis and also provide an insight into the identification of potential targets for drug and vaccine development.