4ET0

Crystal structure of circularly permuted human asparaginase-like protein 1

Summary for 4ET0

• Entry DOI: 10.2210/pdb4et0/pdb
• Related: 3TKJ
• Descriptor: L-asparaginase, SODIUM ION (2 entities in total)
• Functional Keywords: hydrolase
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: Q7L266
• Total number of polymer chains: 2
• Total formula weight: 67580.32

Authors

Li, W.Z.,Yogesha, S.D.,Zhang, Y. (deposition date: 2012-04-23, release date: 2012-09-26, Last modification date: 2024-02-28)

Primary citation

Li, W.,Cantor, J.R.,Yogesha, S.D.,Yang, S.,Chantranupong, L.,Liu, J.Q.,Agnello, G.,Georgiou, G.,Stone, E.M.,Zhang, Y.
Uncoupling Intramolecular Processing and Substrate Hydrolysis in the N-Terminal Nucleophile Hydrolase hASRGL1 by Circular Permutation.
Acs Chem.Biol., 7:1840-1847, 2012

PubMed Abstract: The human asparaginase-like protein 1 (hASRGL1) catalyzes the hydrolysis of l-asparagine and isoaspartyl-dipeptides. As an N-terminal nucleophile (Ntn) hydrolase superfamily member, the active form of hASRGL1 is generated by an intramolecular cleavage step with Thr168 as the catalytic residue. However, in vitro, autoprocessing is incomplete (~50%), fettering the biophysical characterization of hASRGL1. We circumvented this obstacle by constructing a circularly permuted hASRGL1 that uncoupled the autoprocessing reaction, allowing us to kinetically and structurally characterize this enzyme and the precursor-like hASRGL1-Thr168Ala variant. Crystallographic and biochemical evidence suggest an activation mechanism where a torsional restraint on the Thr168 side chain helps drive the intramolecular processing reaction. Cleavage and formation of the active site releases the torsional restriction on Thr168, which is facilitated by a small conserved Gly-rich loop near the active site that allows the conformational changes necessary for activation.

PubMed: 22891768
DOI: 10.1021/cb300232n

Experimental method

X-RAY DIFFRACTION (3.3 Å)