title: A novel gene, algK, from the alginate biosynthesis cluster of Pseudomonas aeruginosa.
abstract: Colonization of the cystic fibrosis lung by Pseudomonas aeruginosa is greatly facilitated by the production of an exopolysaccharide called alginate. Many of the enzymes involved in alginate biosynthesis are clustered in an operon at 34 min on the P. aeruginosa chromosome. This paper reports the nucleotide sequence of a previously uncharacterized gene, algK, which lies between the alg44 and algE genes of the operon. DNA sequencing data for algK predicted a protein product of approximately 52.5 kDa which contains a putative 27 amino acid N-terminal signal sequence and a consensus cleavage and lipid attachment site for signal peptidase II. Expression of algK using either T7 or tac promoter expression systems, in vivo labelling studies with [35S]methionine, indicated that algK encodes a polypeptide of approximately 53 kDa which is processed to a mature protein of approximately 50 kDa when expressed in Escherichia coli or P. aeruginosa, in agreement with the nucleotide sequence analysis. Results from an algK-beta-lactamase fusion survey support this interpretation and also provide evidence that mature AlgK is entirely periplasmic and is probably membrane-anchored.
authors.affiliation: Institute of Cell and Molecular Biology, Division of Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JR, UK.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Aarons
authors.affiliation: Institute of Cell and Molecular Biology, Division of Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JR, UK.
authors.forename: Ian W
authors.initials: IW
authors.lastname: Sutherland
authors.affiliation: Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Chakrabarty
authors.affiliation: Institute of Cell and Molecular Biology, Division of Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JR, UK.
authors.forename: Maurice P
authors.initials: MP
authors.lastname: Gallagher
mesh_terms: D000464:Alginates / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D002451:Cell Compartmentation; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D011498:Protein Precursors / Q000096:biosynthesis; D011499:Protein Processing, Post-Translational; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D016364:Reading Frames; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA
chemical_list: D000464:Alginates; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins