1SD4

Crystal Structure of a SeMet derivative of BlaI at 2.0 A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.203 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structures of the BlaI repressor from Staphylococcus aureus and its complex with DNA: insights into transcriptional regulation of the bla and mec operons

Safo, M.K.Zhao, Q.Ko, T.-P.Musayev, F.N.Robinson, H.Scarsdale, N.Wang, A.H.-J.Archer, G.L.

(2005) J.Bacteriol. 187: 1833-1844

  • DOI: 10.1128/JB.187.5.1833-1844.2005
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The 14-kDa BlaI protein represses the transcription of blaZ, the gene encoding beta-lactamase. It is homologous to MecI, which regulates the expression of mecA, the gene encoding the penicillin binding protein PBP2a. These genes mediate resistance to ...

    The 14-kDa BlaI protein represses the transcription of blaZ, the gene encoding beta-lactamase. It is homologous to MecI, which regulates the expression of mecA, the gene encoding the penicillin binding protein PBP2a. These genes mediate resistance to beta-lactam antibiotics in staphylococci. Both repressors can bind either bla or mec DNA promoter-operator sequences. Regulated resistance genes are activated via receptor-mediated cleavage of the repressors. Cleavage is induced when beta-lactam antibiotics bind the extramembrane sensor of the sensor-transducer signaling molecules, BlaR1 or MecR1. The crystal structures of BlaI from Staphylococcus aureus, both in free form and in complex with 32 bp of DNA of the mec operator, have been determined to 2.0- and 2.7-A resolutions, respectively. The structure of MecI, also in free form and in complex with the bla operator, has been previously reported. Both repressors form homodimers, with each monomer composed of an N-terminal DNA binding domain of winged helix-turn-helix topology and a C-terminal dimerization domain. The structure of BlaI in complex with the mec operator shows a protein-DNA interface that is conserved between both mec and bla targets. The recognition helix alpha3 interacts specifically with the conserved TACA/TGTA DNA binding motif. BlaI and, probably, MecI dimers bind to opposite faces of the mec DNA double helix in an up-and-down arrangement, whereas MecI and, probably, BlaI dimers bind to the same DNA face of bla promoter-operator DNA. This is due to the different spacing of mec and bla DNA binding sites. Furthermore, the flexibility of the dimeric proteins may make the C-terminal proteolytic cleavage site more accessible when the repressors are bound to DNA than when they are in solution, suggesting that the induction cascade involves bound rather than free repressor.


    Organizational Affiliation

    Department of Medicinal Chemistry, School of Pharmacy and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, Virginia 23298-0049, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PENICILLINASE REPRESSOR
A, B
126Staphylococcus aureusMutation(s): 0 
Gene Names: blaI (penI)
Find proteins for P0A042 (Staphylococcus aureus)
Go to UniProtKB:  P0A042
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.203 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 64.412α = 90.00
b = 116.362β = 90.00
c = 40.170γ = 90.00
Software Package:
Software NamePurpose
CBASSdata collection
REFMACrefinement
SOLVEphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-08-10
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Version format compliance