Molecular Docking Analysis of Lipoprotein Receptor Antigen I –Causing Endocarditis Interaction with Antibiotics and Immunoglobulins

Abstract

Bacterial endocarditis is a life-threatening infectious disease. In recent years, significant changes have occurred in risk factors, prophylaxis, common causative microorganisms, antibiotic resistance patterns of these organisms, diagnostic criteria, and antibiotic treatment of bacterial endocarditis. The viridans group of streptococci the most common cause of endocarditis, and its lipoprotein receptor antigen proteins (LraI) function as adhesins in several streptococci, as a virulence factor for endocarditis. The increasing trend of antibiotic resistance towards endocarditis, there is an immediate need to identify the mechanisms of molecular interactions of these virulence factors with common antibiotics and immunoglobulins.  Thus, in this study, a group of five Streptococcal enzymes of LraI family (SsaB from Streptococcus sanguinis, ScaA from S. gordonii, PsaA from S. pneumoniae, FimA from S. parasanguinis, and ScbA from S. cristatus) were selected and considered as reactive sites. Three dimensional structure of the target receptor LraI family enzymes were docked with the antibiotic molecules using Hex 8.0.0 molecular docking method. The study found no potential affinity between the enzymes (receptors) and the antibiotics (ligands) during the molecular docking. However, a strong binding affinity towards IgM was observed with all the LraI family of five enzymes; hence, IgM was the most efficient antibody that could be used against bacterial endocarditis.