The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial β-Lactamases

• DOI: 10.1128/jb.187.22.7667-7679.2005
• Publication Date: 2005-11-02T22:07:52Z
• Authors: Justin A. McDonough; Kari E. Hacker; Anthony R. Flores; Martin S. Pavelka; Miriam Braunstein
• Keywords: Twin-arginine translocation pathway; Mycobacterium smegmatis

ABSTRACT The twin-arginine translocation (Tat) pathway exports folded proteins across the bacterial cytoplasmic membrane and is responsible for proper extracytoplasmic localization of involved in a variety cellular functions, including pathogenesis. Mycobacterium tuberculosis smegmatis genomes contain open reading frames with homology to components Tat export system (TatABC) as well potential Tat-exported possessing N-terminal signal sequences characteristic motif. Due importance exported virulence factors pathogenesis M. limited understanding mycobacterial protein systems, we sought determine functional nature mycobacteria. Here describe phenotypic analyses Δ tatA tatC deletion mutants , which demonstrated that encode capable exporting substrates. Both displayed growth defect on agar medium hypersensitivity sodium dodecyl sulfate. were also defective active β-lactamases (BlaS) (BlaC), both possess sequences. Tat-dependent BlaC was further revealed by mutation Finally, replacement native sequence predicted phospholipase C (PlcA PlcB) resulted an enzymatically ′BlaC. Thus, ′BlaC can be used genetic reporter