1FGS

FOLYLPOLYGLUTAMATE SYNTHETASE FROM LACTOBACILLUS CASEI

Summary for 1FGS

• Entry DOI: 10.2210/pdb1fgs/pdb
• Descriptor: FOLYLPOLYGLUTAMATE SYNTHETASE, MAGNESIUM ION, PYROPHOSPHATE 2-, ... (4 entities in total)
• Functional Keywords: synthetase, ligase
• Biological source: Lactobacillus casei
• Total number of polymer chains: 1
• Total formula weight: 46854.28

Authors

Sun, X.,Bognar, A.,Baker, E.,Smith, C. (deposition date: 1998-04-29, release date: 1999-05-04, Last modification date: 2024-02-07)

Primary citation

Sun, X.,Bognar, A.L.,Baker, E.N.,Smith, C.A.
Structural homologies with ATP- and folate-binding enzymes in the crystal structure of folylpolyglutamate synthetase.
Proc.Natl.Acad.Sci.USA, 95:6647-6652, 1998

PubMed Abstract: Folylpolyglutamate synthetase, which is responsible for the addition of a polyglutamate tail to folate and folate derivatives, is an ATP-dependent enzyme isolated from eukaryotic and bacterial sources, where it plays a key role in the retention of the intracellular folate pool. Here, we report the 2.4-A resolution crystal structure of the MgATP complex of the enzyme from Lactobacillus casei. The structural analysis reveals that folylpolyglutamate synthetase is a modular protein consisting of two domains, one with a typical mononucleotide-binding fold and the other strikingly similar to the folate-binding enzyme dihydrofolate reductase. We have located the active site of the enzyme in a large interdomain cleft adjacent to an ATP-binding P-loop motif. Opposite this site, in the C domain, a cavity likely to be the folate binding site has been identified, and inspection of this cavity and the surrounding protein structure suggests that the glutamate tail of the substrate may project into the active site. A further feature of the structure is a well defined Omega loop, which contributes both to the active site and to interdomain interactions. The determination of the structure of this enzyme represents the first step toward the elucidation of the molecular mechanism of polyglutamylation of folates and antifolates.

PubMed: 9618466
DOI: 10.1073/pnas.95.12.6647

Experimental method

X-RAY DIFFRACTION (2.4 Å)