title: Novel active site in Escherichia coli fructose 1,6-bisphosphate aldolase.
abstract: The molecular architecture of the Class II E. coli fructose 1,6-bisphosphate aldolase dimer was determined to 1.6 A resolution. The subunit fold corresponds to a singly wound alpha/beta-barrel with an active site located on the beta-barrel carboxyl side of each subunit. In each subunit there are two mutually exclusive zinc metal ion binding sites, 3.2 A apart; the exclusivity is mediated by a conformational transition involving side-chain rotations by chelating histidine residues. A binding site for K+ and NH4+ activators was found near the beta-barrel centre. Although Class I and Class II aldolases catalyse identical reactions, their active sites do not share common amino acid residues, are structurally dissimilar, and from sequence comparisons appear to be evolutionary distinct.
authors.affiliation: Départment de biochimie, Université de Montréal, Canada.
authors.forename: N S
authors.initials: NS
authors.lastname: Blom
authors.forename: S
authors.initials: S
authors.lastname: Tétreault
authors.forename: R
authors.initials: R
authors.lastname: Coulombe
authors.forename: J
authors.initials: J
authors.lastname: Sygusch
mesh_terms: D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology*; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013379:Substrate Specificity
chemical_list: D005634:Fructose-Bisphosphate Aldolase