Molecular cloning and expression in Escherichia coli of genes encoding pectate lyase and pectin methylesterase activities from Bacteroides thetaiotaomicron.

Bacteroides thetaiotaomicron strain 217 can use pectins as a sole carbon source. Preliminary characterization of the pectinolytic enzymes revealed three complementary activities in this strain: a pectin methylesterase (PME), a pectate lyase (PL) and a polygalacturonase (PG), which were all inducible by pectin or polygalacturonate. Use of the lambdoid phage replacement vector lambda EMBL3 allowed a 13.

Cloning and expression in Escherichia coli of dextranase genes from Bacteroides thetaiotaomicron.

A genomic bank was constructed in Escherichia coli HB101, consisting of DNA fragments from Bacteroides thetaiotaomicron strain 489 inserted within the vector pBR322. By screening on complex medium containing blue dextran, 10 stable dextranase-positive (Dex+) clones were isolated. Seven groups of Dex+ inserts were identified on the basis of their restriction maps and hybridization responses.