Two mammalian glucosamine-6-phosphate deaminases: a structural and genetic study.
Glucosamine-6-phosphate deaminase (EC 3.5.99.6) is an allosteric enzyme that catalyzes the reversible conversion of D-glucosamine-6-phosphate into D-fructose-6-phosphate and ammonium. Here we describe the existence of two mammalian glucosamine-6-phosphate deaminase enzymes. We present the crystallographic structure of one of them, the long human glucosamine-6-phosphate deaminase, at 1.75 A resolution. Crystals belong to the space group P2(1)2(1)2(1) and present a whole hexamer in the asymmetric unit. The active-site lid (residues 162-182) presented significant structural differences among monomers. Interestingly the region with the largest differences, when compared with the Escherichia coli homologue, was found to be close to the active site. These structural differences can be related to the kinetic and allosteric properties of both mammalian enzymes.
Arreola
Rodrigo
R
Instituto de Biotecnología, Universidad Nacional Autónoma de México, PO Box 510-3, Cuernavaca, 62250 Morelos, Mexico. arreola@ibt.unam.mx
Valderrama
Brenda
B
Morante
Maria L
ML
Horjales
Eduardo
E
D019747:Aldose-Ketose Isomerases / Q000737:chemistry* / Q000235:genetics*; D000495:Allosteric Site; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D006224:Cricetinae; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D007527:Isoenzymes; C020582:glucosamine-6-phosphate isomerase; D019747:Aldose-Ketose Isomerases