title: Crystallization and preliminary X-ray crystallographic investigations on several thermostable forms of a Bacillus subtilis lipase.
abstract: Bacillus subtilis lipase loses activity above pH 10.5 and below pH 6.0. However, at low pH, i.e. below pH 5.0, the lipase acquires remarkable thermostability. Activity was unaltered for 2 h at 323 K at pH 4.0-5.0, although at pH values above 7.0 the activity was lost rapidly within minutes. Circular-dichroism studies indicate significant changes in the tertiary structure of the lipase, whereas the secondary-structural content remained unaltered. To elucidate the structural basis of the enhanced thermostability, three different forms have been crystallized at low pH along with three crystal forms of two thermostable mutants obtained using a directed-evolution approach.
authors.affiliation: Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
authors.forename: Eerappa
authors.initials: E
authors.lastname: Rajakumara
authors.forename: Priyamvada
authors.initials: P
authors.lastname: Acharya
authors.forename: Shoeb
authors.initials: S
authors.lastname: Ahmad
authors.forename: Vellaiah M
authors.initials: VM
authors.lastname: Shanmugam
authors.forename: Nalam M
authors.initials: NM
authors.lastname: Rao
authors.forename: Rajan
authors.initials: R
authors.lastname: Sankaranarayanan
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D003460:Crystallization; D018360:Crystallography, X-Ray; D019020:Directed Molecular Evolution; D004795:Enzyme Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry* / Q000235:genetics; D017354:Point Mutation / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C079999:LipA protein, Bacteria; D008049:Lipase