title: Collagen-like sequences stabilize homotrimers of a bacterial hydrolase.
abstract: Pullulanase from Klebsiella pneumoniae strain FG9 has an unusual N-terminal amino acid sequence that includes six repeats of the tripeptide Gly-X-Pro. This type of sequence is characteristic of animal collagens and collagen-like proteins which form triple helical structures. We have investigated the molecular organization of this bacterial pullulanase isolated from the cell surface of Escherichia coli cells that carry the cloned FG9 pulA (pullulanase encoding) gene. Non-denaturing polyacrylamide gel analysis shows that pullulanase exists as higher order, apparently homogeneous, structures. We have used highly purified bacterial collagenase to probe the role of the collagen-like region and we demonstrate that this feature is essential for non-covalent association of pullulanase homotrimers. In addition we show collagenase-specific release of cell-bound pullulanase.
authors.affiliation: Biotechnology Unit, University of Leeds, UK.
authors.forename: B M
authors.initials: BM
authors.lastname: Charalambous
authors.forename: J N
authors.initials: JN
authors.lastname: Keen
authors.forename: M J
authors.initials: MJ
authors.lastname: McPherson
mesh_terms: D000595:Amino Acid Sequence; D001345:Autoradiography; D001483:Base Sequence; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D006026:Glycoside Hydrolases / Q000235:genetics; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D046911:Macromolecular Substances; D003012:Microbial Collagenase / Q000378:metabolism; D008969:Molecular Sequence Data
chemical_list: D046911:Macromolecular Substances; D006026:Glycoside Hydrolases; C100181:pullulanase; D003012:Microbial Collagenase