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Title: Crystal Structure of the Vibrio Cholerae Quorum-Sensing Regulatory Protein HapR

Abstract

Quorum sensing in Vibrio cholerae involves signaling between two-component sensor protein kinases and the response regulator LuxO to control the expression of the master regulator HapR. HapR, in turn, plays a central role in regulating a number of important processes, such as virulence gene expression and biofilm formation. We have determined the crystal structure of HapR to 2.2- Angstroms resolution. Its structure reveals a dimeric, two-domain molecule with an all-helical structure that is strongly conserved with members of the TetR family of transcriptional regulators. The N-terminal DNA-binding domain contains a helix-turn-helix DNA-binding motif and alteration of certain residues in this domain completely abolishes the ability of HapR to bind to DNA, alleviating repression of both virulence gene expression and biofilm formation. The C-terminal dimerization domain contains a unique solvent accessible tunnel connected to an amphipathic cavity, which by analogy with other TetR regulators, may serve as a binding pocket for an as-yet-unidentified ligand.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
959601
Report Number(s):
BNL-82587-2009-JA
Journal ID: ISSN 0021-9193; JOBAAY; TRN: US201016%%745
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Bacteriology; Journal Volume: 189
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL STRUCTURE; DIMERIZATION; DNA; GENES; PHOSPHOTRANSFERASES; PROTEINS; RESIDUES; RESOLUTION; SOLVENTS; VIRULENCE; national synchrotron light source

Citation Formats

DeSilva,R., Kovacikova, G., Lin, W., Taylor, R., Skorupski, K., and Kull, F. Crystal Structure of the Vibrio Cholerae Quorum-Sensing Regulatory Protein HapR. United States: N. p., 2007. Web. doi:10.1128/JB.01807-06.
DeSilva,R., Kovacikova, G., Lin, W., Taylor, R., Skorupski, K., & Kull, F. Crystal Structure of the Vibrio Cholerae Quorum-Sensing Regulatory Protein HapR. United States. doi:10.1128/JB.01807-06.
DeSilva,R., Kovacikova, G., Lin, W., Taylor, R., Skorupski, K., and Kull, F. Mon . "Crystal Structure of the Vibrio Cholerae Quorum-Sensing Regulatory Protein HapR". United States. doi:10.1128/JB.01807-06.
@article{osti_959601,
title = {Crystal Structure of the Vibrio Cholerae Quorum-Sensing Regulatory Protein HapR},
author = {DeSilva,R. and Kovacikova, G. and Lin, W. and Taylor, R. and Skorupski, K. and Kull, F.},
abstractNote = {Quorum sensing in Vibrio cholerae involves signaling between two-component sensor protein kinases and the response regulator LuxO to control the expression of the master regulator HapR. HapR, in turn, plays a central role in regulating a number of important processes, such as virulence gene expression and biofilm formation. We have determined the crystal structure of HapR to 2.2- Angstroms resolution. Its structure reveals a dimeric, two-domain molecule with an all-helical structure that is strongly conserved with members of the TetR family of transcriptional regulators. The N-terminal DNA-binding domain contains a helix-turn-helix DNA-binding motif and alteration of certain residues in this domain completely abolishes the ability of HapR to bind to DNA, alleviating repression of both virulence gene expression and biofilm formation. The C-terminal dimerization domain contains a unique solvent accessible tunnel connected to an amphipathic cavity, which by analogy with other TetR regulators, may serve as a binding pocket for an as-yet-unidentified ligand.},
doi = {10.1128/JB.01807-06},
journal = {Journal of Bacteriology},
number = ,
volume = 189,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
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  • VC0702, a conserved hypothetical protein of unknown function from Vibrio cholerae, resides in a three-gene operon containing the MbaA gene that encodes for a GGDEF and EAL domain-containing protein which is involved in regulating formation of the extracellular matrix of biofilms in Vibrio cholerae. The VC0702 crystal structure has been determined at 2.0 Angstroms and refined to R{sub work} = 22.8% and R{sub free} = 26.3%. VC0702 crystallized in an orthorhombic crystal lattice in the C2221 space group with dimensions of a = 66.61 Angstroms, b = 88.118 Angstroms, and c = 118.35 Angstroms with a homodimer in the asymmetricmore » unit. VC0702, which forms a mixed {alpha} + {beta} three-layered {alpha}{beta}{alpha} sandwich, belongs to the Pfam DUF84 and COG1986 families of proteins. Sequence conservation within the DUF84 and COG1986 families was used to identify a conserved patch of surface residues that define a cleft and potential substrate-binding site in VC0702. The three-dimensional structure of VC0702 is similar to that of Mj0226 from Methanococcus janeschii, which has been identified as a novel NTPase that binds NTP in a deep cleft similarly located to the conserved patch of surface residues that define an analogous cleft in VC0702. Collectively, the data suggest that VC0702 may have a biochemical function that involves NTP binding and phosphatase activity of some kind, and is likely involved in regulation of the signaling pathway that controls biofilm formation and maintenance in Vibrio cholerae.« less
  • No abstract prepared.
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