J. Oconnor et al., EXPRESSION, PURIFICATION, AND INITIAL CHARACTERIZATION OF THE RECOMBINANT STORAGE PROTEIN-PRECURSOR OF THEOBROMA-CACAO, Protein expression and purification, 7(4), 1996, pp. 377-383
The gene encoding the 67-kDa cocoa storage protein precursor has been
cloned from Theobroma cacao and expressed in Escherichia coli using th
e pET expression system. The recombinant storage protein has been rena
tured from inclusion bodies at 30 degrees C using 20 mM glycine-NaOH b
uffer, pH 10.0, containing 1 mM oxidized glutathione and 0.1% Brij. Th
e renatured protein was purified and demonstrated to adopt a stable na
tive conformation by optical spectroscopy. Secondary structure analysi
s from circular dichroism indicated the protein to be 23% alpha-helix
and 38% beta-sheet, in close agreement with values obtained using a se
condary structure prediction program. (C) 1996 Academic Press, Inc.