title: Characterization of the Azotobacter vinelandii algC gene involved in alginate and lipopolysaccharide production.
abstract: Azotobacter vinelandii is a soil gamma-proteobacteria that fixes nitrogen and forms desiccation-resistant cysts. The exopolysaccharide alginate is an integral part of the layers surrounding the cysts. Here, we reported the cloning of A. vinelandii algC, encoding the enzyme catalyzing the second step of alginate pathway. We showed that AlgC is involved not only in alginate production, but also in lipopolysaccharide (LPS) synthesis and that it seems to have both phosphomannomutase and phosphoglucomutase activities. The transcriptional analysis of the A. vinelandii algC gene showed that it contained two start sites, one of which was dependent on the alternative sigma factor AlgU/AlgT. This finding explains why alginate biosynthesis is dependent on AlgU activity, since all other alginate biosynthetic genes have been characterized previously and algC is the only alginate structural gene that is directly transcribed by this sigma factor.
authors.affiliation: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Gaona
authors.forename: Cinthia
authors.initials: C
authors.lastname: Núñez
authors.forename: Joanna B
authors.initials: JB
authors.lastname: Goldberg
authors.forename: Alicia S
authors.initials: AS
authors.lastname: Linford
authors.forename: Rebeca
authors.initials: R
authors.lastname: Nájera
authors.forename: Miguel
authors.initials: M
authors.lastname: Castañeda
authors.forename: Josefina
authors.initials: J
authors.lastname: Guzmán
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Espín
authors.forename: Gloria
authors.initials: G
authors.lastname: Soberón-Chávez
mesh_terms: D000464:Alginates; D016948:Azotobacter vinelandii / Q000201:enzymology* / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D005798:Genes, Bacterial; D020723:Glucuronic Acid / Q000096:biosynthesis*; D006603:Hexuronic Acids; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010733:Phosphoglucomutase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017875:Phosphotransferases (Phosphomutases) / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
chemical_list: D000464:Alginates; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006603:Hexuronic Acids; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D014157:Transcription Factors; D020723:Glucuronic Acid; D017875:Phosphotransferases (Phosphomutases); D010733:Phosphoglucomutase; C052799:phosphomannomutase