title: Three multidomain esterases from the cellulolytic rumen anaerobe Ruminococcus flavefaciens 17 that carry divergent dockerin sequences.
abstract: Three enzymes carrying esterase domains have been identified in the rumen cellulolytic anaerobe Ruminococcus flavefaciens 17. The newly characterized CesA gene product (768 amino acids) includes an N-terminal acetylesterase domain and an unidentified C-terminal domain, while the previously characterized XynB enzyme (781 amino acids) includes an internal acetylesterase domain in addition to its N-terminal xylanase catalytic domain. A third gene, xynE, is predicted to encode a multidomain enzyme of 792 amino acids including a family 11 xylanase domain and a C-terminal esterase domain. The esterase domains from CesA and XynB share significant sequence identity (44%) and belong to carbohydrate esterase family 3; both domains are shown here to be capable of deacetylating acetylated xylans, but no evidence was found for ferulic acid esterase activity. The esterase domain of XynE, however, shares 42% amino acid identity with a family 1 phenolic acid esterase domain identified from Clostridum thermocellum XynZ. XynB, XynE and CesA all contain dockerin-like regions in addition to their catalytic domains, suggesting that these enzymes form part of a cellulosome-like multienzyme complex. The dockerin sequences of CesA and XynE differ significantly from those previously described in R. flavefaciens polysaccharidases, including XynB, suggesting that they might represent distinct dockerin specificities.
authors.affiliation: Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK1.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Aurilia
authors.affiliation: Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK1.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Martin
authors.affiliation: Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK1.
authors.forename: Sheila I
authors.initials: SI
authors.lastname: McCrae
authors.affiliation: Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK1.
authors.forename: Karen P
authors.initials: KP
authors.lastname: Scott
authors.affiliation: Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK1.
authors.forename: Marco T
authors.initials: MT
authors.lastname: Rincon
authors.affiliation: Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK1.
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Flint
mesh_terms: D000115:Acetylesterase / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001406:Bacillaceae / Q000201:enzymology* / Q000235:genetics*; D001483:Base Sequence; D020134:Catalytic Domain / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004950:Esterases / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary / Q000235:genetics; D012417:Rumen / Q000382:microbiology; D017386:Sequence Homology, Amino Acid; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000235:genetics
chemical_list: D017931:DNA Primers; D004950:Esterases; D000115:Acetylesterase; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase