Mycobacterium tuberculosis TtfA is a Highly Stable Membrane-Anchored DNA-Binding Protein

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a deadly intracellular pathogen, with a persistent infectivity and high morbidity rate. Mtb has successfully evaded drugs and modern antibiotics, while also developing resistance and adaptability. To obtain newer avenues for therapeutics against Mtb, we proposed to identify and characterize membrane proteins of Mtb. To this end, we report the successful characterization of the locus rv0383c, which codes for a 284-residue membrane-anchored protein. We show that the protein product, named TtfA, possesses an N-terminal transmembrane helix, a low complexity region, an α + β central region, and a C-terminally highly unstructured region. Our studies reveal that the extramembranous domain possesses non-specific DNA-binding ability. Additionally, TtfA folds into a highly stable structure that resists thermal unfolding. TtfA is selectively sensitive to the surrounding pH. The promising outcomes we obtain with TtfA as one of the next-generation antibiotic targets against Mtb can pave the way for characterizing other membrane proteins toward finding long-term cures for this endemic disease.