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1cnv
From Proteopedia
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|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1cnv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cnv OCA], [http://www.ebi.ac.uk/pdbsum/1cnv PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1cnv RCSB]</span> | ||
}} | }} | ||
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[[Category: plant chitinase]] | [[Category: plant chitinase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:25:09 2008'' |
Revision as of 16:25, 30 March 2008
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| , resolution 1.65Å | |||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF CONCANAVALIN B AT 1.65 A RESOLUTION
Overview
Seeds of Canavalia ensiformis (jack bean) contain besides large amounts of canavalin and concanavalin A, a protein with a molecular mass of 33,800 which has been named concanavalin B. Although concanavalin B shares about 40% sequence identity with plant chitinases belonging to glycosyl hydrolase family 18, no chitinase activity could be detected for this protein. To resolve this incongruity concanavalin B was crystallised and its three-dimensional structure determined at 1.65 A (1 A = 0.1 nm) resolution. The structure consists of a single domain with a (beta/alpha)8 topology. A 30 amino acid residue long loop occurs between the second beta-strand of the barrel and the second alpha-helix. This extended loop is unusual for the (beta/alpha)8 topology, but appears in a similar conformation in the structures of the seed protein narbonin and several chitinases as well. Two non-proline cis-peptide bonds are present in the structure of concanavalin B: Ser34-Phe, and Trp265-Asn. This structural feature is rarely observed in proteins, but could also be identified in the three-dimensional structures of family 18 chitinases and narbonin in coincident positions. In the chitinases the aromatic residues of the non-proline cis-peptides have been proposed to have a function in the binding of the substrate. The region in concanavalin B, where in chitinases the active site is located, shows two significant differences. First, the catalytic glutamic acid is a glutamine in concanavalin B. Second, although part of the substrate binding cleft of the chitinases is present in concanavalin B, it is much shorter. From this we conclude that concanavalin B and family 18 chitinases are closely related, but that concanavalin B has lost its enzymatic function. It still may act as a carbohydrate binding protein, however.
About this Structure
1CNV is a Single protein structure of sequence from Canavalia ensiformis. Full crystallographic information is available from OCA.
Reference
Crystal structure of concanavalin B at 1.65 A resolution. An "inactivated" chitinase from seeds of Canavalia ensiformis., Hennig M, Jansonius JN, Terwisscha van Scheltinga AC, Dijkstra BW, Schlesier B, J Mol Biol. 1995 Nov 24;254(2):237-46. PMID:7490746
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