title: Structure of the D140N mutant of chitinase B from Serratia marcescens at 1.45 A resolution.
abstract: The crystal structure of the inactive D140N mutant of Serratia marcescens was refined to 1.45 A resolution. The structure of the mutant was essentially identical to that of the wild type, with the exception of a rotation of Asp142 in the catalytic centre. In the mutant, this residue interacts with the catalytic acid (Glu144) and not with residue 140 as in the wild type. Thus, the 500-fold decrease in activity in the D140N mutant seems to be largely mediated by an effect on Asp142, confirming the crucial role of the latter residue in catalysis.
authors.affiliation: Department of Chemistry and Biotechnology, Agricultural University of Norway, 1432 As, Norway.
authors.forename: G
authors.initials: G
authors.lastname: Kolstad
authors.forename: B
authors.initials: B
authors.lastname: Synstad
authors.forename: V G H
authors.initials: VG
authors.lastname: Eijsink
authors.forename: D M F
authors.initials: DM
authors.lastname: van Aalten
mesh_terms: D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain; D002688:Chitinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D011487:Protein Conformation; D012706:Serratia marcescens / Q000201:enzymology*
chemical_list: D010940:Plant Proteins; D001224:Aspartic Acid; D002688:Chitinases; C094255:PLC-B protein, Phytolacca americana