Galactoside Acetyltransferase in Complex with IPTG and Coenzyme A

Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.176 

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This is version 1.5 of the entry. See complete history


Structure of the lac operon galactoside acetyltransferase.

Wang, X.G.Olsen, L.R.Roderick, S.L.

(2002) Structure 10: 581-588

  • DOI: https://doi.org/10.1016/s0969-2126(02)00741-4
  • Primary Citation of Related Structures:  
    1KQA, 1KRR, 1KRU, 1KRV

  • PubMed Abstract: 

    The galactoside acetyltransferase (thiogalactoside transacetylase) of Escherichia coli (GAT, LacA, EC is a gene product of the classical lac operon. GAT may assist cellular detoxification by acetylating nonmetabolizable pyranosides, thereby preventing their reentry into the cell. The structure of GAT has been solved in binary complexes with acetyl-CoA or CoA and in ternary complexes with CoA and the nonphysiological acceptor substrates isopropyl beta-D-thiogalactoside (IPTG) or p-nitrophenyl beta-D-galactopyranoside (PNPbetaGal). A hydrophobic cleft that binds the thioisopropyl and p-nitrophenyl aglycones of IPTG and PNPbetaGal may discriminate against substrates with hydrophilic substituents at this position, such as lactose, or inducers of the lac operon. An extended loop projecting from the left-handed parallel beta helix domain contributes His115, which is in position to facilitate attack of the C6-hydroxyl group of the substrate on the thioester.

  • Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
203Escherichia coliMutation(s): 0 
Gene Names: lacA
Find proteins for P07464 (Escherichia coli (strain K12))
Explore P07464 
Go to UniProtKB:  P07464
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP07464
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.176 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.1α = 90
b = 183.8β = 90
c = 121.8γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-GENdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-04-10
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.5: 2024-02-14
    Changes: Data collection, Database references, Structure summary