4Y23

Crystal structure of T399A precursor mutant protein of gamma-glutamyl transpeptidase from Bacillus licheniformis

Summary for 4Y23

• Entry DOI: 10.2210/pdb4y23/pdb
• Related: 2EOW 4OTT 4OTU
• Descriptor: Gamma glutamyl transpeptidase,Gamma-glutamyltranspeptidase, SODIUM ION (3 entities in total)
• Functional Keywords: ntn hydrolase, precursor, gamma-gtp, post-translational processing, maturation, transferase
• Biological source: Bacillus licheniformis; More
• Total number of polymer chains: 1
• Total formula weight: 64087.26

Authors

Pica, A.,Merlino, A. (deposition date: 2015-02-09, release date: 2015-11-18, Last modification date: 2024-01-10)

Primary citation

Pica, A.,Chi, M.C.,Chen, Y.Y.,d'Ischia, M.,Lin, L.L.,Merlino, A.
The maturation mechanism of gamma-glutamyl transpeptidases: Insights from the crystal structure of a precursor mimic of the enzyme from Bacillus licheniformis and from site-directed mutagenesis studies.
Biochim.Biophys.Acta, 1864:195-203, 2015

PubMed Abstract: γ-Glutamyl transpeptidases (γ-GTs) are members of N-terminal nucleophile hydrolase superfamily. They are synthetized as single-chain precursors, which are then cleaved to form mature enzymes. Basic aspects of autocatalytic processing of these pro-enzymes are still unknown. Here we describe the X-ray structure of the precursor mimic of Bacillus licheniformis γ-GT (BlGT), obtained by mutating catalytically important threonine to alanine (T399A-BlGT), and report results of autoprocessing of mutants of His401, Thr415, Thr417, Glu419 and Arg571. Data suggest that Thr417 is in a competent position to activate the catalytic threonine (Thr399) for nucleophilic attack of the scissile peptide bond and that Thr415 plays a major role in assisting the process. On the basis of these new structural results, a possible mechanism of autoprocessing is proposed. This mechanism, which guesses the existence of a six-membered transition state involving one carbonyl and two hydroxyl groups, is in agreement with all the available experimental data collected on γ-GTs from different species and with our new Ala-scanning mutagenesis data.

PubMed: 26536828
DOI: 10.1016/j.bbapap.2015.10.006

Experimental method

X-RAY DIFFRACTION (2.89 Å)