Structural Insights into the Hydrolysis and Polymorphism of Methotrexate Polyglutamate by Zebrafish gamma-Glutamyl Hydrolase
- Authors
- Chuankhayan, P., Kao, T.T., Lin, C.C., Guan, H.H., Nakagawa, A., Fu, T.F., and Chen, C.J.
- ID
- ZDB-PUB-130923-5
- Date
- 2013
- Source
- Journal of medicinal chemistry 56(19): 7625-7635 (Journal)
- Registered Authors
- Fu, Tzu-Fun, Kao, Tseng-Ting
- Keywords
- none
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Antineoplastic Agents/chemistry*
- Catalytic Domain
- Crystallization
- Humans
- Hydrolysis
- Methotrexate/analogs & derivatives*
- Methotrexate/chemistry
- Models, Molecular
- Molecular Conformation
- Molecular Sequence Data
- Mutation
- Polyglutamic Acid/analogs & derivatives*
- Polyglutamic Acid/chemistry
- Sequence Homology, Amino Acid
- Zebrafish Proteins/chemistry*
- Zebrafish Proteins/genetics
- gamma-Glutamyl Hydrolase/chemistry*
- gamma-Glutamyl Hydrolase/genetics
- PubMed
- 24028568 Full text @ J. Med. Chem.
γGlutamyl hydrolases (γGH) catalyze the hydrolysis of γ-linked glutamate residues from the polyglutamyl of folates and antifolates, such as methotrexate (MTX), a widely used anti-cancer drug. We describe the first crystal structures of the endopeptidase-type γGH (zγGH) from zebrafish and the mutant complexes with MTX(Glu)5 and hydrolyzed MTX(Glu)1 that reveal the complete set of key residues involved in hydrolysis and the substrate-binding subsites (–1 to +2). The side chain of Phe20 and the 6-methylpterin ring of MTX(Glu)5 invoke π-π interactions to promote distinct concerted conformational alterations involving ~90° rotations in the complexes with the zγGH-C108A and zγGH-H218N mutant proteins. Structural geometries of the MTX(Glu)5 and hydrolyzed MTX(Glu)1 in the mutant complexes differ significantly from those of the previously known MTX(Glu)1, providing polymorphic information. Together with the structural comparison and the activity analysis, these results shed light on the catalytic mechanism and substrate recognition of zγGH and other γglutamyl hydrolases.