Functional characterization of the Rv2182c protein of Mycobacterium tuberculosis

Melissa S Beaty, Purdue University

Abstract

Mycobacterium tuberculosis (Mtb) affects the world globally with over one third of the world’s population having a latent form of tuberculosis in which the pathogen is in a dormant state. Much is unknown about how Mtb incorporates fatty acids into lipids for survival in its latent form. Acyltransferases, enzymes that transfer a fatty acyl group, are critical for the accumulation of lipids that store metabolic energy for use during the dormant state of the pathogen inside the human body. Understanding the functions of mycobacterial acyltransferases catalyzing the glycerol phosphate pathway will help determine how these enzymes incorporate fatty acids into lipids for survival of Mtb during dormancy. The Rv2182c gene of Mtb encodes a putative acyltransferase and its function has not been studied previously. Therefore, we expressed the Rv2182c protein in Escherichia coli in order to investigate its functions biochemically. We purified Rv2182c and assayed its enzymatic activity. We discovered that the purified Rv2182c protein was able to incorporate radiolabeled fatty acyl-coenzyme A into lipid acceptors. We also examined the effect of Rv2182c on the metabolism of fatty acids in the E. coli heterologous host cell. We observed that the metabolic incorporation of radiolabeled fatty acids into polar lipids by intact E. coli cells was significantly increased. We also observed changes in the growth rate of E. coli cells expressing the Rv2182c protein in LB medium. Based on our studies, we propose that Rv2182c functions as an acyltransferase potentially involved in the remodeling of polar membrane lipids.

Degree

M.S.

Advisors

Daniel, Purdue University.

Subject Area

Biochemistry

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