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Solid phase synthesis and biological evaluation of enantiomerically pure wasp toxin analogues PhTX‐343 and PhTX‐12
Author(s) -
Strømgaard Kristian,
Bjørnsdottir Inga,
Andersen Kim,
Brierley Matthew J.,
Rizoli Silvio,
Eldursi Nuri,
Mellor Ian R.,
Usherwood Peter N.R.,
Hansen Steen H.,
KrogsgaardLarsen Povl,
Jaroszewski Jerzy W.
Publication year - 2000
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(2000)12:2<93::aid-chir6>3.0.co;2-b
Subject(s) - chemistry , enantiomer , ionotropic effect , acetylcholine receptor , chromatography , biophysics , stereochemistry , receptor , glutamate receptor , biochemistry , biology
PhTX‐343 and PhTX‐12, analogues of the natural polyamine wasp toxin PhTX‐433, were synthesised in 40–60% yields as pure enantiomers using solid phase synthesis techniques. Capillary electrophoresis procedures were developed for chiral separation and determination of enantiomeric purity (ee) of the enantiomers of PhTX‐343 and PhTX‐12. The methods were optimised with respect to chiral selector, buffer pH, and temperature around the capillary. Thus, rac ‐PhTX‐343 was resolved using a separation buffer containing 30 mM heptakis‐(2,6‐di‐ O ‐methyl)‐β‐cyclodextrin in 50 mM 6‐aminocarproic acid (pH 4.0) at 15°C. rac ‐PhTX‐12 was not resolvable in this system, but could be resolved using a separation buffer containing 10% w/v of dextrin 10, a linear maltodextrin, in 50 mM 6‐aminocaproic acid (pH 4.0) at 15°C. Using these methods, the optical purity of the synthetic enantiomers was determined to be ee > 99%. The enantiomers were also characterised by chiroptical methods. The antagonist potency of the enantiomers was tested on nicotinic acetylcholine receptors (human muscle‐type nAChR) expressed in TE671 cells, ionotropic glutamate receptors in Xenopus laevis oocytes (expressing recombinant GluR1flop receptors), and locust muscle ionotropic glutamate receptors sensitive to quisqualate (qGluR). The potencies of each pair of enantiomers were similar (eudismic ratio close to 1). Chirality 12:93–102, 2000. © 2000 Wiley‐Liss, Inc.