title: X-ray structural analysis of compensating mutations at the barnase-barstar interface.
abstract: The crystal structure of the barstar mutants (Y29P) and (Y29D, Y30W) as well as that of the complexes of barstar(Y29P) with wild-type barnase and barnase(H102K) have been determined. These barstar mutants compensate for the dramatic loss of barnase-barstar interaction energy caused by a single mutation of the barnase active site His-102 to a lysine. The latter introduces an uncompensated charge in the pocket at the surface of barstar where Lys-102 is located. The analysis of the structures suggests a mechanism for this compensation based on the solvation of the charge of Lys-102. Additional compensation occurs through the formation of a hydrogen bond.
authors.affiliation: Laboratoire de Physique, Centre d'Etudes Pharmaceutiques, Châtenay-Malabry, France.
authors.forename: C
authors.initials: C
authors.lastname: Martin
authors.forename: R
authors.initials: R
authors.lastname: Hartley
authors.forename: Y
authors.initials: Y
authors.lastname: Mauguen
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism; D006639:Histidine; D008239:Lysine; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D017433:Protein Structure, Secondary; D012260:Ribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; C057438:barstar protein, Bacillus amyloliquefaciens; D006639:Histidine; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease; D008239:Lysine