The 2.3 {angstrom} crystal structure of cholera toxin B subunit pentamer: Choleragenoid

Technical Report · Thu Feb 01 04:00:00 EST 1996

DOI:https://doi.org/10.2172/205742· OSTI ID:205742

Zhang, Rong-Guang; Westbrook, M L ^[1]; Maulik, P R; Reed, R A; Shipley, G ^[2]; Westbrook, E M ^[1]; Scott, D L; Otwinowski, Z ^[3]

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1. Argonne National Lab., IL (United States)
2. Boston Univ., MA (United States). School of Medicine
3. Yale Univ., New Haven, CT (United States)

Cholera toxin, a heterohexameric AB{sub 5} enterotoxin released by Vibrio cholera, induces a profuse secretory diarrhea in susceptible hosts. Choleragenoid, the B subunit pentamer of cholera toxin, directs the enzymatic A subunit to its target by binding to GM{sub 1} gangliosides exposed on the luminal surface of intestinal epithelial cells. We have solved the crystal structure of choleragenoid at 2.3 {Angstrom} resolution by combining single isomorphous replacement with non-crystallographic symmetry averaging. The structure of the B subunits, and their pentameric arrangement, closely resembles that reported for the intact holotoxin (choleragen), the heat-labile enterotoxin from E. coli, and for a choleragenoid-GM{sub 1} pentasaccharide complex. In the absence of the A subunit the central cavity of the B pentamer is a highly solvated channel. The binding of the A subunit or the receptor pentasaccharide to choleragenoid has only a modest effect on the local stereochemistry and does not perceptibly alter the subunit interface.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 205742
• Report Number(s): ANL/CMB/PP--83545; ON: DE96006541
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AMINO ACID SEQUENCE
BIOCHEMICAL REACTION KINETICS
CHOLERA
CRYSTALS
ENDOTOXINS
GANGLIOSIDES
PROTEIN STRUCTURE
RESOLUTION
X-RAY DIFFRACTION