LysX2 is a Mycobacterium tuberculosis membrane protein with an extracytoplasmic MprF-like domain.

Background: Aminoacyl-phosphatidylglycerol (aaPG) synthases are bacterial enzymes that usually catalyze transfer of aminoacyl residues to the plasma membrane phospholipid phosphatidylglycerol (PG). The result is introduction of positive charges onto the cytoplasmic membrane, yielding reduced affinity towards cationic antimicrobial peptides, and increased resistance to acidic environments. Therefore, these enzymes represent an important defense mechanism for many pathogens, including Staphylococcus aureus and Mycobacterium tuberculosis (Mtb), which are known to encode for lysyl-(Lys)-PG synthase MprF and LysX, respectively.

Lipid and Lipoarabinomannan Isolation and Characterization.

The very high content of structurally diverse and biologically active lipids of exotic structures is the hallmark of Mycobacteria. As such the lipid composition is commonly used to characterize mycobacterial strains at the species and type-species levels. The present chapter describes the methods that allow the purification of the most commonly isolated biologically active lipids and those used for analyzing extractable lipids and their constituents, cell wall-linked mycolic acids (MA), and lipoarabinomannan (LAM).

Impact of the epoxide hydrolase EphD on the metabolism of mycolic acids in mycobacteria.

Mycolic acids are the hallmark of the cell envelope in mycobacteria, which include the important human pathogens and Mycolic acids are very long C60-C90 α-alkyl β-hydroxy fatty acids having a variety of functional groups on their hydrocarbon chain that define several mycolate types. Mycobacteria also produce an unusually large number of putative epoxide hydrolases, but the physiological functions of these enzymes are still unclear. Here, we report that the mycobacterial epoxide hydrolase EphD is involved in mycolic acid metabolism.

Increased Vancomycin Susceptibility in Mycobacteria: a New Approach To Identify Synergistic Activity against Multidrug-Resistant Mycobacteria.

Mycobacterium tuberculosis is wrapped in complex waxes, impermeable to most antibiotics. Comparing Mycobacterium bovis BCG and M. tuberculosis mutants that lack phthiocerol dimycocerosates (PDIM) and/or phenolic glycolipids with wild-type strains, we observed that glycopeptides strongly inhibited PDIM-deprived mycobacteria.

Lipid and lipoarabinomannan isolation and characterization.

Mycobacteria are microorganisms that contain a very high content of structurally diverse lipids, some of them being biologically active substances. As such the lipid composition is commonly used to characterize mycobacterial strains at the species and type-species level. This chapter describes the methods that allow the purification of the most commonly isolated biologically active lipids and those used for analyzing extractable lipids and their constituents, cell wall-linked mycolic acids and lipoarabinomannan (LAM).