Gamma-glutamyl cyclotransferase

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 

wwPDB Validation   3D Report Full Report

This is version 1.4 of the entry. See complete history


The identification and structural characterization of C7orf24 as gamma-glutamyl cyclotransferase. An essential enzyme in the gamma-glutamyl cycle

Oakley, A.J.Yamada, T.Liu, D.Coggan, M.Clark, A.G.Board, P.G.

(2008) J Biol Chem 283: 22031-22042

  • DOI: https://doi.org/10.1074/jbc.M803623200
  • Primary Citation of Related Structures:  
    2PN7, 2RBH, 3CRY

  • PubMed Abstract: 

    The hypothetical protein C7orf24 has been implicated as a cancer marker with a potential role in cell proliferation. We have identified C7orf24 as gamma-glutamyl cyclotransferase (GGCT) that catalyzes the formation of 5-oxoproline (pyroglutamic acid) from gamma-glutamyl dipeptides and potentially plays a significant role in glutathione homeostasis. In the present study we have identified the first cDNA clones encoding a gamma-glutamyl cyclotransferase. The GGCT gene is located on chromosome 7p14-15 and consists of four exons that span 8 kb. The primary sequence is 188 amino acids in length and is unlike any protein of known function. We crystallized functional recombinant gamma-glutamyl cyclotransferase and determined its structure at 1.7 A resolution. The enzyme is a dimer of 20,994-Da subunits. The topology of GGCT is unrelated to other enzymes associated with cyclotransferase-like activity. The fold was originally classified as "BtrG-like," a small family that only includes structures of hypothetical proteins from Mus musculus, Escherichia coli, Pyrococcus horikoshii, and Arabidopsis thaliana. Since this is the first member of this family with a defined function, we propose to refer to this structure as the gamma-glutamyl cyclotransferase fold. We have identified a potential active site pocket that contains a highly conserved glutamic acid (Glu(98)) and propose that it acts as a general acid/base in the reaction mechanism. Mutation of Glu(98) to Ala or Gln completely inactivates the enzyme without altering the overall fold.

  • Organizational Affiliation

    Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Gamma-glutamyl cyclotransferase
A, B
188Homo sapiensMutation(s): 1 
Gene Names: C7orf24GGCTCRF21
EC: (PDB Primary Data), (UniProt)
UniProt & NIH Common Fund Data Resources
Find proteins for O75223 (Homo sapiens)
Explore O75223 
Go to UniProtKB:  O75223
PHAROS:  O75223
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO75223
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 34.926α = 90
b = 99.406β = 90
c = 99.948γ = 90
Software Package:
Software NamePurpose
MAR345dtbdata collection
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-10-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Refinement description, Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description
  • Version 1.3: 2021-11-10
    Changes: Database references
  • Version 1.4: 2023-10-25
    Changes: Data collection, Refinement description