InterPro domain: IPR012334

This entry covers proteins that are closely related to the pectolytic enzyme, pectin lyase, which act as virulence factors. These proteins include pectate lyase, iota-carrageenase, and glycoside hydrolases from family 28 (such as galacturonases). Pectin lyases, pectate lyases and galacturonases all act on forms of pectin, one of the main components of the cell wall. When the backbone of pectin is methylated it is known as pectin, and can be cleaved by pectin lyase, a microbial virulence factor [ 1 ]. When the backbone of pectin is demethylated it is known as pectate, and can be cleaved by pectate lyase virulence factors, or hydrolysed by polygalacturonases [ 2 , 3 ]. Iota-carrageenase is an enzyme that degrades carrageenan, a main component of the cell walls of various marine red algae. Unlike other carrageenase enzymes, iota-carrageenase belongs to the glycoside hydrolase structural family [ 4 ]. All these enzymes display a beta-helical structure.

1. Two crystal structures of pectin lyase A from Aspergillus reveal a pH driven conformational change and striking divergence in the substrate-binding clefts of pectin and pectate lyases. Structure 5, 677-89
2. Pectate lyases, cell wall degradation and fruit softening. J. Exp. Bot. 53, 2115-9
3. The X-ray structure of Aspergillus aculeatus polygalacturonase and a modeled structure of the polygalacturonase-octagalacturonate complex. J. Mol. Biol. 311, 863-78
4. The iota-carrageenase of Alteromonas fortis. A beta-helix fold-containing enzyme for the degradation of a highly polyanionic polysaccharide. J. Biol. Chem. 276, 40202-9