title: C-terminal elongation of growth-blocking peptide enhances its biological activity and micelle binding affinity.
abstract: 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.
authors.affiliation: Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Umetsu
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Aizawa
authors.forename: Kaori
authors.initials: K
authors.lastname: Muto
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Kamiya
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kumaki
authors.forename: Mineyuki
authors.initials: M
authors.lastname: Mizuguchi
authors.forename: Makoto
authors.initials: M
authors.lastname: Demura
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Hayakawa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kawano
mesh_terms: 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
chemical_list: D019476:Insect Proteins; D008823:Micelles; D010455:Peptides