title: Purification, crystallization, and preliminary x-ray studies of a bifunctional 5,10-methenyl/methylene-tetrahydrofolate cyclohydrolase/dehydrogenase from Escherichia coli.
abstract: A bifunctional enzyme that catalyzes the conversion of formyltetrahydrofolate to methylene-tetrahydrofolate (5,10-methenyltetrahydrofolate cyclohydrolase and 5,10-methylene tetrahydrofolate dehydrogenase), has been subcloned from a cDNA library, purified to homogeneity, and crystallized. The crystals belong to space group I222, with unit cell dimensions of a = 64.5 A, b = 84.9 A, c = 146.1 A. The crystal unit cell and diffraction is consistent with an asymmetric unit consisting of the enzyme monomer, and a specific volume of the unit cell of 3.2 A3/Da. The crystals diffract to at least 2.8 A resolution after flash-cooling, when using a rotating anode x-ray source and an RAXIS image plate detector. A 2.56 A resolution native data set has been collected at beamline X12-C at the NSLS.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, USA.
authors.forename: E
authors.initials: E
authors.lastname: Cheung
authors.forename: L
authors.initials: L
authors.lastname: D'Ari
authors.forename: J C
authors.initials: JC
authors.lastname: Rabinowitz
authors.forename: D H
authors.initials: DH
authors.lastname: Dyer
authors.forename: J Y
authors.initials: JY
authors.lastname: Huang
authors.forename: B L
authors.initials: BL
authors.lastname: Stoddard
mesh_terms: D000619:Aminohydrolases / Q000737:chemistry* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000737:chemistry*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology*; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP) / Q000737:chemistry* / Q000302:isolation & purification; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D009097:Multienzyme Complexes; C055342:methylene tetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP); D000619:Aminohydrolases