6DZ8

Crystal structure of S. aureus penicillin binding protein 4 (PBP4) mutant (S75C)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.86 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Recognition of Peptidoglycan Fragments by the Transpeptidase PBP4 FromStaphylococcus aureus.

Maya-Martinez, R.Alexander, J.A.N.Otten, C.F.Ayala, I.Vollmer, D.Gray, J.Bougault, C.M.Burt, A.Laguri, C.Fonvielle, M.Arthur, M.Strynadka, N.C.J.Vollmer, W.Simorre, J.P.

(2018) Front Microbiol 9: 3223-3223

  • DOI: https://doi.org/10.3389/fmicb.2018.03223
  • Primary Citation of Related Structures:  
    6DZ8

  • PubMed Abstract: 

    Peptidoglycan (PG) is an essential component of the cell envelope, maintaining bacterial cell shape and protecting it from bursting due to turgor pressure. The monoderm bacterium Staphylococcus aureus has a highly cross-linked PG, with ~90% of peptide stems participating in DD-cross-links and up to 15 peptide stems connected with each other. These cross-links are formed in transpeptidation reactions catalyzed by penicillin-binding proteins (PBPs) of classes A and B. Most S. aureus strains have three housekeeping PBPs with this function (PBP1, PBP2, and PBP3) but MRSA strains have acquired a third class B PBP, PBP2a, which is encoded by the mecA gene and required for the expression of high-level resistance to β-lactams. Another housekeeping PBP of S. aureus is PBP4, which belongs to the class C PBPs, and hence would be expected to have PG hydrolase (DD-carboxypeptidase or DD-endopeptidase) activity. However, previous works showed that, unexpectedly, PBP4 has transpeptidase activity that significantly contributes to both the high level of cross-linking in the PG of S. aureus and to the low level of β-lactam resistance in the absence of PBP2a. To gain insights into this unusual activity of PBP4, we studied by NMR spectroscopy its interaction in vitro with different substrates, including intact peptidoglycan, synthetic peptide stems, muropeptides, and long glycan chains with uncross-linked peptide stems. PBP4 showed no affinity for the complex, intact peptidoglycan or the smallest isolated peptide stems. Transpeptidase activity of PBP4 was verified with the disaccharide peptide subunits (muropeptides) in vitro , producing cyclic dimer and multimer products; these assays also showed a designed PBP4(S75C) nucleophile mutant to be inactive. Using this inactive but structurally highly similar variant, liquid-state NMR identified two interaction surfaces in close proximity to the central nucleophile position that can accommodate the potential donor and acceptor stems for the transpeptidation reaction. A PBP4:muropeptide model structure was built from these experimental restraints, which provides new mechanistic insights into mecA independent resistance to β-lactams in S. aureus .


  • Organizational Affiliation

    University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Penicillin-binding protein 4
A, B
359Staphylococcus aureus subsp. aureus COLMutation(s): 1 
Gene Names: pbp4SACOL0699
UniProt
Find proteins for A0A0H2WY27 (Staphylococcus aureus (strain COL))
Explore A0A0H2WY27 
Go to UniProtKB:  A0A0H2WY27
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0H2WY27
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.86 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 104.511α = 90
b = 89.73β = 98.09
c = 77.489γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Canadian Institutes of Health Research (CIHR)Canada--

Revision History  (Full details and data files)

  • Version 1.0: 2018-12-19
    Type: Initial release
  • Version 1.1: 2019-02-20
    Changes: Data collection, Database references
  • Version 1.2: 2020-01-08
    Changes: Author supporting evidence
  • Version 1.3: 2023-10-11
    Changes: Data collection, Database references, Derived calculations, Refinement description