CHOLERA TOXIN B-PENTAMER WITH DECAVALENT LIGAND BMSC-0013

[5-(3,4,5-TRIHYDROXY-6-HYDROXYMETHYL-TETRAHYDRO-PYRAN-2-YLCARBAMOYL)-PENTYL]-CARBAMIC ACID METHYL ESTER

Solution and crystallographic studies of branched multivalent ligands that inhibit the receptor-binding of cholera toxin.

TPQNITDL(CSS)AEYHNTQIHTLNDKIFSYTESLAGKREMAIITFKNGATFQVEVPGSQHIDSQKKAIERMKDTLRIAY
LTEAKVEKLCVWNNKTPHAIAAISMAN

TPQNITDLCAEYHNTQIHTLNDKIFSYTESLAGKREMAIITFKNGATFQVEVPGSQHIDSQKKAIERMKDTLRIAYLTEA
KVEKLCVWNNKTPHAIAAISMAN

PEG 1000, pH 7.5, VAPOR DIFFUSION, SITTING DROP, temperature rtK

Cholera toxin pentamer with receptor GM1 oligosaccharide

Cholera toxin pentamer with pentavalent ligand BMSC-0012

HETEROGEN
Ligand 233 (BMSC-0013) is a decavalent ligand
consisting of a pentacyclen core to which are
attached five long arms, each containing four
'linker' moieties followed by a squaric acid
moiety and then branching to present two monovalent
ligands derived from beta-D-galactose. A single copy
of the decavalent ligand lies on a 2-fold and
straddles two crystallographic asymmetric units.
The central core and linker groups do not satisfy
crystallographic symmetry and are not visible in
the structure and hence not present in this model.
The sulfur atom belongs to an unknown species
(residue 109, chains D-H) constituting a partial-
occupancy improperly formed cysteine disulfide between
residues 9 and 86. That is, ~80% of the time there is a
9-86 disulfide and ~20% of the time there is a 9-???
disulfide.

HELIX
DETERMINATION METHOD: AUTHOR PROVIDED

SHEET
DETERMINATION METHOD: AUTHOR PROVIDED

The crystallized complex contains two CTB pentamers sandwiching a single decavalent ligand. This sandwich spans 2 asymmetric units.