title: Alginate lyase from Klebsiella pneumoniae, subsp. aerogenes: gene cloning, sequence analysis and high-level production in Escherichia coli.
abstract: The alyA gene, encoding a secreted guluronate-specific alginate lyase (Aly) from Klebsiella pneumoniae subsp. aerogenes type 25, has been cloned. DNA sequence analysis reveals two possible translation start sites for the precursor form of Aly and a long open reading frame (ORF) predicted to encode a 287-amino-acid (aa) mature form of Aly, in agreement with N-terminal aa sequence analysis of the protein. Aly has a calculated molecular mass of 31.4 kDa, in good agreement with SDS-PAGE analysis, and a calculated pI of 9.39. Comparison of the deduced aa sequence with a mannuronate-specific lyase from a marine bacterium reveals 19.3% identity and 28.8% similarity with a 9-aa conserved region close to the C terminus, probably of functional or structural significance. There is no obvious sequence similarity with pectate lyases which also catalyse a beta-elimination reaction. Heterologous expression of K. pneumoniae alyA in Escherichia coli yields 10 mg of Aly per litre of culture supernatant, apparently due to non-specific release from the periplasm.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Leeds, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Baron
authors.forename: T Y
authors.initials: TY
authors.lastname: Wong
authors.forename: S J
authors.initials: SJ
authors.lastname: Hicks
authors.forename: P
authors.initials: P
authors.lastname: Gacesa
authors.forename: D
authors.initials: D
authors.lastname: Willcock
authors.forename: M J
authors.initials: MJ
authors.lastname: McPherson
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D010582:Bacteriophage lambda; D001483:Base Sequence; D016384:Consensus Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D011133:Polysaccharide-Lyases / Q000096:biosynthesis / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase