title: Mode of action of Bacillus licheniformis pectin methylesterase on highly methylesterified and acetylated pectins.
abstract: A gene encoding a putative pectinesterase from Bacillus licheniformis DSM13 was cloned and expressed in Escherichia coli. The resulting recombinant enzyme (BliPME) was purified and characterized as a pectin methylesterase. The enzyme showed maximum activity at pH 8.0 and 50°C. BliPME is able to release up to 100% of the methylesters from lime pectin (DM 34-76→DM 0) and up to 73% of all methylesters from SBPs (DM 30-73→DM 14). BliPME efficiently de-methylesterifies lemon pectins and SBPs in a blockwise manner and is quite tolerant towards the acetyl groups present within the SBPs. Detailed analysis of the BliPME-modified pectins using HILIC-MSn and the classical calcium reactivity measurement showed that the enzyme generates pectins with low methylesterification (lime and SBP) and high acetyl content (SBP) while creating blocks of nonmethylesterified galacturonic acid residues. The high activity of BliPME towards highly methylesterified and acetylated pectins makes this novel esterase more efficient in removing methylesters from highly esterified beet pectin compared to other PMEs, e.g. Aspergillus niger PME.
authors.affiliation: Wageningen University, Laboratory of Food Chemistry, Postbus 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Connie
authors.initials: C
authors.lastname: Remoroza
authors.affiliation: Westphalian Wilhelms-University of Münster, Department of Plant Biology and Biotechnology, Schlossplatz 8, 48143 Münster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wagenknecht
authors.affiliation: DuPont Nutrition Biosciences ApS, Edwin Rahrsvej 38, DK-8220 Brabrand, Denmark.
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Buchholt
authors.affiliation: Westphalian Wilhelms-University of Münster, Department of Plant Biology and Biotechnology, Schlossplatz 8, 48143 Münster, Germany.
authors.forename: Bruno M
authors.initials: BM
authors.lastname: Moerschbacher
authors.affiliation: Wageningen University, Laboratory of Food Chemistry, Postbus 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
authors.affiliation: Wageningen University, Laboratory of Food Chemistry, Postbus 17, 6700 AA Wageningen, The Netherlands. Electronic address: henk.schols@wur.nl.
authors.forename: Henk A
authors.initials: HA
authors.lastname: Schols
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D027461:Beta vulgaris; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D004951:Esterification; D008969:Molecular Sequence Data; D010368:Pectins / Q000737:chemistry*; D016415:Sequence Alignment; D017385:Sequence Homology
chemical_list: D001426:Bacterial Proteins; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
keywords: Blockwise; De-methylesterification; Enzymology; Fingerprinting; HILIC–MS/ELSD