title: Identification and isolation of a pectin methylesterase isoform that could be involved in flax cell wall stiffening.
abstract: Pectin methylesterases (PMEs) are ubiquitous enzymes present in the plant cell wall. They catalyse the demethylesterification of homogalacturonic acid units of pectins, which, in turn, can be associated with different physiological phenomena. In this study, different flax (Linum usitatissimum L.) PME isoforms were observed: neutral (pI 7.0 and 7.5, MW: 110 kDa), basic (pI 8.3 and 8.5, MW: 110 kDa) and very basic (pI>9.5, MW: 38 kDa). In an attempt to identify most of the expressed cell wall LuPME isoforms, polyclonal antibodies were raised against a conserved region of PME. These antibodies allowed the purification of the very basic PME isoform (pI 9.5, MW: 36 kDa) from flax cells, designated LuPME5. This isoform corresponds to the Lupme5 cDNA isolated, at the same time, from flax hypocotyls, by using the RACE-PCR technique. Semi-quantitative PCR experiments showed that the Lupme5 transcript was highly expressed in the hypocotyl zones where elongation is being achieved. Thus, this enzyme may be involved in cell wall stiffening.
authors.affiliation: Laboratoire Signaux et régulation chez les végétaux, CNRS UMR 6037, IFRMP 23, Université de Rouen, 76821 Mont-Saint-Aignan Cedex, France.
authors.forename: Suha
authors.initials: S
authors.lastname: Al-Qsous
authors.forename: Emilie
authors.initials: E
authors.lastname: Carpentier
authors.forename: Dominique
authors.initials: D
authors.lastname: Klein-Eude
authors.forename: Carole
authors.initials: C
authors.lastname: Burel
authors.forename: Alain
authors.initials: A
authors.lastname: Mareck
authors.forename: Hélène
authors.initials: H
authors.lastname: Dauchel
authors.forename: Véronique
authors.initials: V
authors.lastname: Gomord
authors.forename: Alain Pierre
authors.initials: AP
authors.lastname: Balangé
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D002478:Cells, Cultured; D019597:Flax / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D018546:Hypocotyl / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism; D007527:Isoenzymes / Q000737:chemistry; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D007527:Isoenzymes; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase