The core and complementary sequence responsible for biological activity of the diapause hormone of the silkworm, Bombyx mori.
To evaluate the structure-function relationship of the diapause hormone of the silkworm, Bombyx mori, the entire molecule and selected fragment and deleted analogues were chemically synthesized to compare their biological activity. The C-terminal pentapeptide amide was the shortest fragment that elicited 11% diapause eggs at maximum, indicating that this sequence is the core-active structure required for a biological response. The full biological response of about 70% diapause eggs was expressed by the C-terminal hexapeptide amide. However, an ED50 value of this peptide amide was 1000-fold higher than that of the parent molecule. The serial elongation of peptide chain lengths toward the N-terminus brought about the sudden decrease in ED50 values at two positions between Arg9-Gly10 and Thr1-Asp2. The deletion of duplicated sequence(s) located in the middle part of the molecule or the truncation of N-terminal region of the parent molecule increased ED50 values but had no effects on response. Thus, N-terminal region and duplicated sequences act as the complementary structures for full potency of diapause hormone.
Aburahi Laboratories, Shionogi and Co., Ltd., Shiga, Japan.
H
H
Saito
Y
Y
Takeuchi
R
R
Takeda
Y
Y
Hayashi
K
K
Watanabe
M
M
Shin
K
K
Imai
M
M
Isobe
O
O
Yamashita
D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000187:drug effects / Q000196:embryology / Q000235:genetics*; D007301:Insect Hormones / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship
D007301:Insect Hormones; D009479:Neuropeptides; D010446:Peptide Fragments; C075027:diapause hormone