Detection and Characterization of a Mycobacterial L-Arabinofuranose ABC Transporter Identified with a Rapid Lipoproteomics Protocol

Abstract

Nutrient uptake is essential for survival of organisms, and carbohydrates serve as a crucial carbon and energy source for most microorganisms. Given the importance of mycobacteria as human pathogens a detailed knowledge of carbohydrate uptake transporters is highly desirable, but currently available information is severely limited and mainly based on in silico analyses. Moreover, there is only very little data available on the in vitro characterization of carbohydrate transporters from mycobacterial species. To overcome these significant limitations there is a strong demand for innovative approaches to experimentally match substrates to ATP-binding cassette (ABC) transporters in a straightforward manner. Our study focuses on the model organism Mycobacterium smegmatis and identifies a mycobacterial ABC transport system based on a rapid label-free mass spectrometry lipoproteomics assay with broad applicability. Further validation and X-ray structure analyses reveal a highly selective mycobacterial L-arabinose uptake system.

Keywords: ABC transporter; L-arabinofuranose-binding protein; carbohydrate transport; carbon uptake; crystal structure; lipoproteins; lipoproteomics; mycobacteria; proteomics analysis; sugar-binding proteins.