title: Crystal structure of cytoplasmic Escherichia coli peptidyl-prolyl isomerase: evidence for decreased mobility of loops upon complexation.
abstract: The structure of the unliganded form of the Escherichia coli cytoplasmic peptidyl-prolyl isomerase (ppiB gene product) in a new crystal form was determined by the molecular replacement method and refined to an R-factor of 16.1% at 2.1 A resolution. The enzyme crystallized in the orthorhombic C2221 space group with unit cell dimensions of a=44.7 A, b=68.2 A and c=102.0 A. Comparison with the reported structure of the enzyme complexed with the tripeptide substrate succinyl-Ala-Pro-Ala-p-nitroanilide revealed subtle changes that occur upon complex formation. There is evidence to suggest that two surface loops have significantly reduced mobility in the complexed structure.
authors.affiliation: Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: K J
authors.initials: KJ
authors.lastname: Edwards
authors.forename: D L
authors.initials: DL
authors.lastname: Ollis
authors.forename: N E
authors.initials: NE
authors.lastname: Dixon
mesh_terms: D000591:Amino Acid Isomerases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D001665:Binding Sites; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D003593:Cytoplasm / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005798:Genes, Bacterial; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008961:Models, Structural; D019696:Peptidylprolyl Isomerase; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013816:Thermodynamics
chemical_list: D002352:Carrier Proteins; D011994:Recombinant Proteins; D000591:Amino Acid Isomerases; D019696:Peptidylprolyl Isomerase