alpha-Galacturonidase(s): A new class of Family 4 glycoside hydrolases with strict specificity and a unique CHEV active site motif

作者：Thompson John^*; Pikis Andreas; Rich Jamie; Hall Barry G; Withers Stephen G

来源：FEBS Letters, 2013, 587(6): 799-803.

DOI：10.1016/j.febslet.2013.02.004

• Glycoside hydrolase Family 4
• alpha-Galacturonidase
• LplD
• CAZy database
• Phylogenetic
• pNP-alpha-D-galactopyranosiduronic acid
• Bacillus subtilis

The catalytic activity of the Family 4 glycosidase LplD protein, whose active site motif is CHEV, is unknown despite its crystal structure having been determined in 2008. Here we identify that activity as being an alpha-galacturonidase whose natural substrate is probably alpha-1,4-di-galacturonate (GalUA(2)). Phylogenetic analysis shows that LplD belongs to a monophyletic clade of CHEV Family 4 enzymes, of which four other members are also shown to be galacturonidases. Family GH 4 enzymes catalyze the cleavage of the glycosidic bond, via a non-canonical redox-assisted mechanism that contrasts with Koshland's double-displacement mechanism. Published by Elsevier B. V. on behalf of the Federation of European Biochemical Societies.

• 出版日期2013-3-18