1fgb: Difference between revisions

Cholera toxin, a heterohexameric AB5 enterotoxin released by Vibrio, cholera, induces a profuse secretory diarrhea in susceptible hosts., Choleragenoid, the B subunit pentamer of cholera toxin, directs the, enzymatic A subunit to its target by binding the GM1 gangliosides exposed, on the luminal surface of intestinal epithelial cells. The crystal, structure of choleragenoid has been independently solved and refined at, 2.4 A resolution by combining single isomorphous replacement with, non-crystallographic symmetry averaging. The structure of the B subunits, and their pentameric arrangement, closely resembles that reported for the, intact holotoxin, choleragen, the heat-labile enterotoxin from Escherichia, coli, and for a choleragenoid-GM1 pentasaccharide complex. In the absence, of the A subunit the central cavity of the B pentamer is a highly solvated, channel. The binding of choleragenoid to the A subunit or to its receptor, pentasaccharide modestly affects the local stereochemistry without, perceptibly altering the subunit interface.

1FGB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Vibrio_cholerae Vibrio cholerae]. Structure known Active Site: GAN. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1FGB OCA].  

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