Crystal structure of heat-labile enterotoxin from Escherichia coli with increased thermostability introduced by an engineered disulfide bond in the A subunit.van den Akker, F., Feil, I.K., Roach, C., Platas, A.A., Merritt, E.A., Hol, W.G.
(1997) Protein Sci. 6: 2644-2649
- PubMed: 9416616
- DOI: 10.1002/pro.5560061219
- PubMed Abstract:
- Crystal Structure of a Cholera Toxin-Related Heat-Labile Enterotoxin from E. Coli
Sixma, T.K.,Pronk, S.E.,Kalk, K.H.,Wartna, E.S.,Van Zanten, B.A.,Witholt, B.,Hol, W.G.
(1991) Nature 351: 371
- Refined Structure of Escherichia Coli Heat-Labile Enterotoxin, a Close Relative of Cholera Toxin
Sixma, T.K.,Kalk, K.H.,Van Zanten, B.A.,Dauter, Z.,Kingma, J.,Witholt, B.,Hol, W.G.
(1993) J.Mol.Biol. 230: 890
Cholera toxin (CT) produced by Vibrio cholerae and heat-labile enterotoxin (LT-I), produced by enterotoxigenic Escherichia coli, are AB5 heterohexamers with an ADP-ribosylating A subunit and a GM1 receptor binding B pentamer. These toxins are among t ...
Cholera toxin (CT) produced by Vibrio cholerae and heat-labile enterotoxin (LT-I), produced by enterotoxigenic Escherichia coli, are AB5 heterohexamers with an ADP-ribosylating A subunit and a GM1 receptor binding B pentamer. These toxins are among the most potent mucosal adjuvants known and, hence, are of interest both for the development of anti-diarrheal vaccines against cholera or enterotoxigenic Escherichia coli diarrhea and also for vaccines in general. However, the A subunits of CT and LT-I are known to be relatively temperature sensitive. To improve the thermostability of LT-I an additional disulfide bond was introduced in the A1 subunit by means of the double mutation N40C and G166C. The crystal structure of this double mutant of LT-I has been determined to 2.0 A resolution. The protein structure of the N40C/G166C double mutant is very similar to the native structure except for a few local shifts near the new disulfide bond. The introduction of this additional disulfide bond increases the thermal stability of the A subunit of LT-I by 6 degrees C. The enhancement in thermostability could make this disulfide bond variant of LT-I of considerable interest for the design of enterotoxin-based vaccines.
Department of Biochemistry, University of Washington, Seattle 98195-7420, USA.