C-terminal elongation of growth-blocking peptide enhances its biological activity and micelle binding affinity.
Growth-blocking peptide (GBP) is a hormone-like peptide that suppresses the growth of the host armyworm. Although the 23-amino acid GBP (1-23 GBP) is expressed in nonparasitized armyworm plasma, the parasitization by wasp produces the 28-amino acid GBP (1-28 GBP) through an elongation of the C-terminal amino acid sequence. In this study, we characterized the GBP variants, which consist of various lengths of the C-terminal region, by comparing their biological activities and three-dimensional structures. The results of an injection study indicate that 1-28 GBP most strongly suppresses larval growth. NMR analysis shows that these peptides have basically the same tertiary structures and that the extension of the C-terminal region is disordered. However, the C-terminal region of 1-28 GBP undergoes a conformational transition from a random coiled state to an alpha-helical state in the presence of dodecylphosphocholine micelles. This suggests that binding of the C-terminal region would affect larval growth activity.
Umetsu
Yoshitaka
Y
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Aizawa
Tomoyasu
T
Muto
Kaori
K
Yamamoto
Hiroko
H
Kamiya
Masakatsu
M
Kumaki
Yasuhiro
Y
Mizuguchi
Mineyuki
M
Demura
Makoto
M
Hayakawa
Yoichi
Y
Kawano
Keiichi
K
D000818:Animals; D006458:Hemolymph / Q000737:chemistry; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics; D008823:Micelles; D009036:Moths / Q000737:chemistry* / Q000235:genetics; D010455:Peptides / Q000737:chemistry* / Q000235:genetics; D020836:Protein Structure, Quaternary / Q000502:physiology; D017433:Protein Structure, Secondary / Q000502:physiology
D019476:Insect Proteins; D008823:Micelles; D010455:Peptides