Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 42.23 kDa 
• Atom Count: 3241 
• Modelled Residue Count: 338 
• Deposited Residue Count: 376 
• Unique protein chains: 1

3CRY

Gamma-glutamyl cyclotransferase

• PDB DOI: 10.2210/pdb3CRY/pdb

• Classification: TRANSFERASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2008-04-08 Released: 2008-04-29 
• Deposition Author(s): Oakley, A.J., Board, P.G.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.70 Å
• R-Value Free: 0.223 
• R-Value Work: 0.178 
• R-Value Observed: 0.180 

Literature

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

• PubMed: 18515354 
• DOI: 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.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Gamma-glutamyl cyclotransferase	A, B	188	Homo sapiens	Mutation(s): 1  Gene Names: GGCT, C7orf24, CRF21 EC: 4.3.2.9
UniProt & NIH Common Fund Data Resources
Find proteins for O75223 (Homo sapiens) Explore O75223  Go to UniProtKB:  O75223
PHAROS:  O75223

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ACT	C [auth A], D [auth B], E [auth B]	ACETATE ION C2 H3 O2 QTBSBXVTEAMEQO-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.70 Å
• R-Value Free: 0.223 
• R-Value Work: 0.178 
• R-Value Observed: 0.180 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 34.828	α = 90
b = 98.135	β = 90
c = 100.499	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
Blu-Ice	data collection
MOSFLM	data reduction
SCALA	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2008-04-08 
• Released Date: 2008-04-29 
Deposition Author(s): Oakley, A.J., Board, P.G.

Revision History  

• Version 1.0: 2008-04-29
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2017-10-25
  Changes: Refinement description
• Version 1.3: 2021-11-10
  Changes: Database references, Derived calculations