1ltb is a 7 chain structure with sequence from Escherichia coli. The September 2005 RCSB PDB Molecule of the Month feature on Cholera Toxin by David S. Goodsell is 10.2210/rcsb_pdb/mom_2005_9. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
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.
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[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Merritt EA, Pronk SE, Sixma TK, Kalk KH, van Zanten BA, Hol WG. Structure of partially-activated E. coli heat-labile enterotoxin (LT) at 2.6 A resolution. FEBS Lett. 1994 Jan 3;337(1):88-92. PMID:8276119
