Systematic mutational analysis of the LytTR DNA binding domain of Staphylococcus aureus virulence gene transcription factor AgrA

Abstract

Most DNA-binding bacterial transcription factors contact DNA through a recognition α-helix in their DNA-binding domains. An emerging class of DNA-binding transcription factors, predominantly found in pathogenic bacteria interact with the DNA via a relatively novel type of DNA-binding domain, called the LytTR domain, which mainly comprises β strands. Even though the crystal structure of the LytTR domain of the virulence gene transcription factor AgrA from Staphylococcus aureus bound to its cognate DNA sequence is available, the contribution of specific amino acid residues in the LytTR domain of AgrA to transcription activation remains elusive. Here, for the first time, we have systematically investigated the role of amino acid residues in transcription activation in a LytTR domain-containing transcription factor. Our analysis, which involves in vivo and in vitro analyses and molecular dynamics simulations of S. aureus AgrA identifies a highly conserved tyrosine residue, Y229, as a major amino acid determinant for maximal activation of transcription by AgrA and provides novel insights into structure–function relationships in S. aureus AgrA.

ω-Hydroxyemodin Limits Staphylococcus aureus Quorum Sensing-Mediated Pathogenesis and Inflammation

“…3B). Docking studies positioned OHM in a pocket between the side chains of H200 and Y229, with Y229 recently identified as a major contributor to maximal AgrA activity (46), and three residues, R218, S231, and V232, which make direct interactions with bound DNA in the AgrA-DNA crystal structure (38). Given this, together with observations that OHM is within hydrogen bonding distance of R218 and that naturally occurring mutations at R218 result in agr-negative phenotypes (47), we predicted that OHM would inhibit AgrA binding to promoter DNA.…”

“…This residue, which is strictly conserved across multiple staphylococcal species (46), is required for agr function and contributes to AgrA binding to agr promoter DNA (38,47). Although the potential exists for OHM to drive selection for an alternative amino acid at residue 218, any such mutation would likely result in agr dysfunction.…”

Norlichexanthone Reduces Virulence Gene Expression and Biofilm Formation in Staphylococcus aureus

“…Expression and purification of AgrAc was carried out as previously described with minor modifications [34]. E .…”

Gene Regulation, Two Component Regulatory Systems, and Adaptive Responses in Treponema Denticola

“…Most RRs interact with DNA through a recognition alpha helix located within a DNA binding domain. Studies of the S. aureus AgrA (accessory gene regulator A), a LytTR RR, have provided insight into the LytTR-DNA interaction (Koenig et al 2004;Nicod et al 2014;Rode et al 2007;Sidote et al 2008;Traber and Novick 2006). AgrA is a cytoplasmic protein that possesses an N-terminal REC domain of 124 amino acids and a C-terminal LytTR domain of 98 residues.…”