1LT3

HEAT-LABILE ENTEROTOXIN DOUBLE MUTANT N40C/G166C

Summary for 1LT3

• Entry DOI: 10.2210/pdb1lt3/pdb
• Related PRD ID: PRD_900004
• Descriptor: HEAT-LABILE ENTEROTOXIN, beta-D-galactopyranose-(1-4)-beta-D-glucopyranose (3 entities in total)
• Functional Keywords: enterotoxin
• Biological source: Escherichia coli; More
• Total number of polymer chains: 6
• Total formula weight: 88635.92

Authors

Van Den Akker, F.,Hol, W.G.J. (deposition date: 1997-04-12, release date: 1997-07-07, Last modification date: 2024-10-30)

Primary citation

van den Akker, F.,Feil, I.K.,Roach, C.,Platas, A.A.,Merritt, E.A.,Hol, W.G.
Crystal structure of heat-labile enterotoxin from Escherichia coli with increased thermostability introduced by an engineered disulfide bond in the A subunit.
Protein Sci., 6:2644-2649, 1997

PubMed Abstract: 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.

PubMed: 9416616

Experimental method

X-RAY DIFFRACTION (2 Å)