4rbr

Publication Abstract from PubMed

Staphylococcus aureus is responsible for a large number of diverse infections worldwide. In order to support its pathogenic lifestyle, S. aureus has to regulate the expression of virulence factors in a coordinated fashion. One of the central regulators of the S. aureus virulence regulatory networks is the transcription factor Repressor of Toxins (Rot). Rot plays a key role in regulating S. aureus virulence through activation or repression of promoters that control expression of a large number of critical virulence factors. However, the mechanism by which Rot-mediates gene regulation has remained elusive. Here, we have we determined the crystal structure of Rot and used this information to probe the contribution made by specific residues to Rot function. Rot was found to form a dimer, with each monomer harboring a Winged-Helix-Turn-Helix (WHTH) DNA binding motif. Despite an overall acidic pI, the asymmetric electrostatic charge profile suggests that Rot can orient the WHTH domain to bind DNA. Structure-based site-directed mutagenesis studies demonstrated that R91, at the tip of the wing, plays an important role in DNA-binding, likely through interaction with the minor groove. We also found that Y66, predicted to bind within the major groove, contributes to Rot interaction with target promoters. Evaluation of Rot binding to different activated and repressed promoters revealed that certain mutations on Rot exhibit promoter-specific effects, suggesting for the first time that Rot differentially interacts with target promoters. This work provides insight into a precise mechanism by which Rot controls virulence factor regulation in S. aureus.

Structure-based functional characterization of Repressor of Toxin (Rot), a central regulator of Staphylococcus aureus virulence.,Killikelly A, Benson MA, Ohneck EA, Sampson JM, Jakoncic J, Spurrier B, Torres VJ, Kong XP J Bacteriol. 2014 Oct 20. pii: JB.02317-14. PMID:25331435^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.