2CLA

CRYSTAL STRUCTURE OF THE ASP-199-ASN MUTANT OF CHLORAMPHENICOL ACETYLTRANSFERASE TO 2.35 ANGSTROMS RESOLUTION. STRUCTURAL CONSEQUENCES OF DISRUPTION OF A BURIED SALT-BRIDGE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Observed: 0.152 

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This is version 1.3 of the entry. See complete history


Literature

Crystal structure of the aspartic acid-199----asparagine mutant of chloramphenicol acetyltransferase to 2.35-A resolution: structural consequences of disruption of a buried salt bridge.

Gibbs, M.R.Moody, P.C.Leslie, A.G.

(1990) Biochemistry 29: 11261-11265

  • DOI: https://doi.org/10.1021/bi00503a015
  • Primary Citation of Related Structures:  
    2CLA

  • PubMed Abstract: 

    The crystal structure of the Asp-199----Asn mutant of chloramphenicol acetyltransferase (CAT) has been determined to 2.35-A resolution. In wild-type CAT Asp-199 is involved in a fully buried intrasubunit salt bridge with Arg-18, an interaction that is adjacent to the active site. Replacement of aspartate with asparagine by site-directed mutagenesis disrupts this salt bridge and causes extensive conformational changes within the active site. The imidazole group of the catalytically essential His-195 is reoriented, with the loss of interactions thought to stabilize the preferred tautomer of this residue. Arg-18 and Asn-199 form three new intersubunit interactions as a result of large side-chain torsion angle changes which cause the movement of two polypeptide loops, some residues of which are up to 20 A away from the site of the mutation. The new interactions of Arg-18 and Asn-199 compensate for the loss of the buried salt bridge and afford near-wild-type thermostability to Asn-199 CAT, albeit with a greatly reduced activity.


  • Organizational Affiliation

    Blackett Laboratory, Imperial College of Science, Technology, and Medicine, London, U.K.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CHLORAMPHENICOL ACETYLTRANSFERASE213Escherichia coliMutation(s): 0 
EC: 2.3.1.28
UniProt
Find proteins for P00484 (Escherichia coli)
Explore P00484 
Go to UniProtKB:  P00484
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00484
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Observed: 0.152 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 107.7α = 90
b = 107.7β = 90
c = 124.4γ = 120
Software Package:
Software NamePurpose
PROLSQrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1990-07-15
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations, Other