1ltb
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Biological toxicity of E. coli heat-labile enterotoxin and the closely | + | Biological toxicity of E. coli heat-labile enterotoxin and the closely related cholera toxin requires that the assembled toxin be activated by proteolytic cleavage of the A subunit and reduction of a disulfide bond internal to the A subunit. The structural role served by this reduction and cleavage is not known, however. We have crystallographically determined the structure of the E. coli heat-labile enterotoxin AB5 hexamer in which the A subunit has been cleaved by trypsin between residues 192 and 195. The toxin is thus partially activated, in that it has been cleaved but the disulfide bond has not been reduced. The structure of the A subunit in the cleaved toxin is substantially the same as that previously observed for the uncleaved AB5 structure, suggesting that although such cleavage is required for biological activity of the toxin it does not by itself cause a conformational change. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Hol, W | + | [[Category: Hol, W G.J.]] |
| - | [[Category: Merritt, E | + | [[Category: Merritt, E A.]] |
| - | [[Category: Sixma, T | + | [[Category: Sixma, T K.]] |
[[Category: enterotoxin]] | [[Category: enterotoxin]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:48:14 2008'' |
Revision as of 11:48, 21 February 2008
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2.6 ANGSTROMS CRYSTAL STRUCTURE OF PARTIALLY-ACTIVATED E. COLI HEAT-LABILE ENTEROTOXIN (LT)
Overview
Biological toxicity of E. coli heat-labile enterotoxin and the closely related cholera toxin requires that the assembled toxin be activated by proteolytic cleavage of the A subunit and reduction of a disulfide bond internal to the A subunit. The structural role served by this reduction and cleavage is not known, however. We have crystallographically determined the structure of the E. coli heat-labile enterotoxin AB5 hexamer in which the A subunit has been cleaved by trypsin between residues 192 and 195. The toxin is thus partially activated, in that it has been cleaved but the disulfide bond has not been reduced. The structure of the A subunit in the cleaved toxin is substantially the same as that previously observed for the uncleaved AB5 structure, suggesting that although such cleavage is required for biological activity of the toxin it does not by itself cause a conformational change.
About this Structure
1LTB is a Protein complex structure of sequences from Escherichia coli. The following page contains interesting information on the relation of 1LTB with [Cholera Toxin]. Full crystallographic information is available from OCA.
Reference
Structure of partially-activated E. coli heat-labile enterotoxin (LT) at 2.6 A resolution., Merritt EA, Pronk SE, Sixma TK, Kalk KH, van Zanten BA, Hol WG, FEBS Lett. 1994 Jan 3;337(1):88-92. PMID:8276119
Page seeded by OCA on Thu Feb 21 13:48:14 2008
