TY - JOUR
T1 - Structure-activity relations of the dark-colour-inducing neurohormone of locusts
AU - Yerushalmi, Yoram
AU - Bhargava, Kalpana
AU - Gilon, Chaim
AU - Pener, Meir Paul
PY - 2002
Y1 - 2002
N2 - The dark-colour-inducing effect of several peptides in comparison to that of the dark-colour-inducing neurohormone (DCIN, [His7]-corazonin) of locusts was investigated by a bioassay based on nymphs of a DCIN-deficient albino mutant of Locusta migratoria. The study was aimed at elucidating the active part of the DCIN and to explore the contribution of its amino acids to the activity. Graded doses of all peptides were injected in oil. [Arg7]-corazonin and DCIN were equally effective. Certain arthropod neuropeptides having the -SXGW- partial sequence (a part of the DCIN and of [Arg7]-corazonin; X=His and X=Arg, respectively) yielded the following findings: Scg-AKH-II (adipokinetic hormone II of Schistocerca gregaria X=Thr), Grb-AKH (adipokinetic hormone of Gryllus bimaculatus X=Thr) and RPCH (red pigment concentrating hormone of crustaceans X=Pro) evoked a moderate darkening response, but Lom-AKH-II (adipokinetic hormone II of L. migratoria X=Ala) was ineffective. Step by step shortening of the sequence of the DCIN at the N-terminal, from pGlu-3-11DCIN to pGlu-9-11DCIN, resulted in a decreasing activity, but even pGlu-9-11DCIN induced a weak response with high doses. Shortening of the DCIN from the C-terminal revealed a moderate activity of 1-7DCIN-NH2 and a weak activity of 1-5DCIN-NH2. An octadecapeptide which induces dark colour in moth larvae, having the pentamer FTPRL-NH2 at its C-terminal, evoked no darkening in the albino locusts. We conclude that although the -SXGW- partial sequence has some role in induction of darkening, for obtaining maximal effect the whole sequence of the DCIN (or of [Arg7]-corazonin) is necessary.
AB - The dark-colour-inducing effect of several peptides in comparison to that of the dark-colour-inducing neurohormone (DCIN, [His7]-corazonin) of locusts was investigated by a bioassay based on nymphs of a DCIN-deficient albino mutant of Locusta migratoria. The study was aimed at elucidating the active part of the DCIN and to explore the contribution of its amino acids to the activity. Graded doses of all peptides were injected in oil. [Arg7]-corazonin and DCIN were equally effective. Certain arthropod neuropeptides having the -SXGW- partial sequence (a part of the DCIN and of [Arg7]-corazonin; X=His and X=Arg, respectively) yielded the following findings: Scg-AKH-II (adipokinetic hormone II of Schistocerca gregaria X=Thr), Grb-AKH (adipokinetic hormone of Gryllus bimaculatus X=Thr) and RPCH (red pigment concentrating hormone of crustaceans X=Pro) evoked a moderate darkening response, but Lom-AKH-II (adipokinetic hormone II of L. migratoria X=Ala) was ineffective. Step by step shortening of the sequence of the DCIN at the N-terminal, from pGlu-3-11DCIN to pGlu-9-11DCIN, resulted in a decreasing activity, but even pGlu-9-11DCIN induced a weak response with high doses. Shortening of the DCIN from the C-terminal revealed a moderate activity of 1-7DCIN-NH2 and a weak activity of 1-5DCIN-NH2. An octadecapeptide which induces dark colour in moth larvae, having the pentamer FTPRL-NH2 at its C-terminal, evoked no darkening in the albino locusts. We conclude that although the -SXGW- partial sequence has some role in induction of darkening, for obtaining maximal effect the whole sequence of the DCIN (or of [Arg7]-corazonin) is necessary.
KW - Corazonin
KW - Dark-colour-inducing neurohormone (DCIN)
KW - DCIN derivatives
KW - Locusta migratoria
KW - Locusts
KW - RPCH/AKH neurohormones
KW - Structure-activity
UR - http://www.scopus.com/inward/record.url?scp=0035983288&partnerID=8YFLogxK
U2 - 10.1016/S0965-1748(01)00180-1
DO - 10.1016/S0965-1748(01)00180-1
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C2 - 12110298
AN - SCOPUS:0035983288
SN - 0965-1748
VL - 32
SP - 909
EP - 917
JO - Insect Biochemistry and Molecular Biology
JF - Insect Biochemistry and Molecular Biology
IS - 8
ER -