Molecular insights into the differential efflux mechanism of Rv1634 protein, a multidrug transporter of major facilitator superfamily in Mycobacterium tuberculosis

Abstract

Currently, multidrug‐resistant tuberculosis (MDR‐TB) is a public health crisis and a major health security threat globally. In Mycobacterium tuberculosis (Mtb), major facilitator superfamily (MFS) is the largest group of secondary active transporters. Along with the transport of their natural substrates, MFS proteins were involved in a drug efflux mechanism that ultimately lead to resistance against available anti‐TB drugs in Mtb. In the present study, the three‐dimensional structure model of an MFS protein, Rv1634, a probable multidrug transporter from Mtb, was generated using homology modeling. The protein structure model was found in inward‐open conformation having 14 transmembrane helices. In addition, a central transport channel was deduced across the protein, and a single binding pocket was identified halfway through the central cavity by structural alignment with the homologous protein structures. Further, Rv1634 protein was studied based on the differential structural behavior of apo and ligand‐bound forms. All the protein systems were inserted into a phospholipid bilayer to characterize the conformational dynamics of the protein using molecular dynamics (MD) simulations. Detailed analysis of the MD trajectories showed the diverse substrate specificity of the binding pocket for the antibiotics that caused differential movement in the ciprofloxacin and norfloxacin, to which Mtb strains have now become resistant. The expulsion of the drugs outside the bacterial cell occurs through the alternating‐access mechanism of N and C‐terminal domains, which is intriguing and essential to the understanding the drug resistance mechanism in pathogenic bacteria.

LC-mHTT-AN2 oversees lactate transport, hypoxia, and glucose homeostasis through dual regulation of MCT-1/4 in the tumor microenvironment

“…To optimize drug binding in the predicted binding pocket, all residues implicated in the substrate binding pocket were included in grid box with 4A spaces for MCT-1 and MCT-4 and docking was performed. After docking, several ligand states were generated based on amino acid interactions and binding a nities, which were visualized using LigPlot+ [ 15 ].…”

The <em>Mycobacterium tuberculosis</em>: A Silent Killer

“…MFS has 12 or 14 transmembrane helix and transport many types of substrates, like anions, cations, amino acids, simple sugars, and drugs. The MTB has 16 open reading frames identified as MSF type efflux pumps; the Rv1634 as associated to fluoroquinolone resistance to NOR and CPX; Rv1258 confer resistance to TET, and aminoglycosides like STM; and EfpA increase the resistance to INH and other antimicrobial compounds [153].…”