Biosynthetic control of molecular weight in the polymerization of the octasaccharide subunits of succinoglycan, a symbiotically important exopolysaccharide of Rhizobium meliloti

Juan E. González, Carlos E. Semino, Lai Xi Wang, Laura E. Castellano-Torres, Graham C. Walker

Producció científica: Article en revista indexadaArticleAvaluat per experts

83 Cites (Scopus)

Resum

Succinoglycan, a symbiotically important exopolysaccharide of Rhizobium meliloti, is composed of polymerized octasaccharide subunits, each of which consists of one galactose and seven glucoses with succinyl, acetyl, and pyruvyl modifications. Production of specific low molecular weight forms of R. meliloti exported and surface polysaccharides, including succinoglycan, appears to be important for nodule invasion. In a previous study of the roles of the various exo gene products in succinoglycan biosynthesis, exoP, exoQ, and exoT mutants were found to synthesize undecaprenol-linked fully modified succinoglycan octasaccharide subunits, suggesting possible roles for their gene products in polymerization or transport. Using improved techniques for analyzing succinoglycan biosynthesis by these mutants, we have obtained evidence indicating that R. meliloti has genetically separable systems for the synthesis of high molecular weight succinoglycan and the synthesis of a specific class of low molecular weight oligosaccharides consisting of dimers and trimers of the octasaccharide subunit. Models to account for our unexpected findings are discussed. Possible roles for the ExoP, ExoQ, and ExoT proteins are compared and contrasted with roles that have been suggested on the basis of homologies to key proteins involved in the biosynthesis of O- antigens and of certain exported or capsular cell surface polysaccharides.

Idioma originalAnglès
Pàgines (de-a)13477-13482
Nombre de pàgines6
RevistaProceedings of the National Academy of Sciences of the United States of America
Volum95
Número23
DOIs
Estat de la publicacióPublicada - 10 de nov. 1998
Publicat externament

Fingerprint

Navegar pels temes de recerca de 'Biosynthetic control of molecular weight in the polymerization of the octasaccharide subunits of succinoglycan, a symbiotically important exopolysaccharide of Rhizobium meliloti'. Junts formen un fingerprint únic.

Com citar-ho