1gxo: Difference between revisions

Enzyme-catalyzed beta-elimination of sugar uronic acids, exemplified by, the degradation of plant cell wall pectins, plays an important role in a, wide spectrum of biological processes ranging from the recycling of plant, biomass through to pathogen virulence. The three-dimensional crystal, structure of the catalytic module of a "family PL-10" polysaccharide, lyase, Pel10Acm from Cellvibrio japonicus, solved at a resolution of 1.3, A, reveals a new polysaccharide lyase fold and is the first example of a, polygalacturonic acid lyase that does not exhibit the "parallel, beta-helix" topology. The "Michaelis" complex of an inactive mutant in, association with the substrate trigalacturonate/Ca2+ reveals the catalytic, machinery harnessed by this polygalacturonate lyase, which displays a, stunning resemblance, presumably through convergent evolution, to the, tetragalacturonic acid complex observed for a structurally unrelated, polygalacturonate lyase from family PL-1. Common coordination of the -1, and +1 subsite saccharide carboxylate groups by a protein-liganded Ca2+, ion, the positioning of an arginine catalytic base in close proximity to, the alpha-carbon hydrogen and numerous other conserved enzyme-substrate, interactions, considered in light of mutagenesis data for both families, suggest a generic polysaccharide anti-beta-elimination mechanism.

1GXO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Cellvibrio_japonicus Cellvibrio japonicus] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Pectate_lyase Pectate lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.2.2 4.2.2.2] Structure known Active Site: AD1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GXO OCA].  

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