Crystal structure of a cholera toxin-related heat-labile enterotoxin from E. coli |
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Authors: | T K Sixma S E Pronk K H Kalk E S Wartna B A van Zanten B Witholt W G Hol |
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Institution: | BIOSON Research Institute, Groningen, The Netherlands. |
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Abstract: | Examination of the structure of Escherichia coli heat-labile enterotoxin in the AB5 complex at a resolution of 2.3A reveals that the doughnut-shaped B pentamer binds the enzymatic A subunit using a hairpin of the A2 fragment, through a highly charged central pore. Putative ganglioside GM1-binding sites on the B subunits are more than 20A removed from the membrane-crossing A1 subunit. This ADP-ribosylating (A1) fragment of the toxin has structural homology with the catalytic region of exotoxin A and hence also to diphtheria toxin. |
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