Mr. Kanost et al., ISOLATION AND CHARACTERIZATION OF APOLIPOPHORIN-III FROM THE GIANT WATER BUG (LETHOCERUS-MEDIUS), Insect biochemistry and molecular biology, 25(7), 1995, pp. 759-764
Upon injection of synthetic adipokinetic hormone, lipophorin from Leth
ocerus medius decreased in ensity and became associated with apolipoph
orin-III (apoLp-III), ApoLp-III isolated from hemolymph of Lethocerus
medius had a M(r) = 19,000 and an amino acid composition high in methi
onine, in comparison with other apoLp-IIIs. Its circular dichroism spe
ctrum was consistent with a protein with secondary structure of predom
inantly alpha-helix, NH2-terminal sequence alignment with apoLp-III se
quences from other species showed a conservation of the hydrophobic or
hydrophilic properties of residues at each position rather than of sp
ecific amino acids, ApoLp-III from Lethocerus medius has the potential
to form amphipathic alpha-helices, similar to those found in the thre
e-dimensional structure of Locusta migratoria apoLp-III. A portion of
the apoLp-III molecules that are not associated with lipophorin contai
ned the blue chromophore, biliverdin.