2006 Fiscal Year Final Research Report Summary
Structural biological analysis of activation mechanism of hematocyte by ENF peptide family
| Project/Area Number |
16370049
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KAWANO Keiichi Hokkaido Univ., Fac.Sci., Prof., 大学院理学研究院, 教授 (10136492)
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| Co-Investigator(Kenkyū-buntansha) |
HAYAKAWA Yoichi Saga Univ., Fac.Agric., Prof., 農学部, 教授 (50164926)
KAWABATA Shun-ichiro Kyushu Univ., Fac.Sci., Prof., 大学院理学研究科, 教授 (90183037)
MIZUGUCHI Mineyuki Univ.Toyama., Fac.Pharm., Assoc.Prof., 大学院医学薬学研究部, 助教授 (30332662)
AIZAWA Tomoyasu Hokkaido Univ., Fac.Adv.Life Sci., Assoc.Prof., 大学院先端生命科学研究院, 助教授 (40333596)
DEMURA Makoto Hokkaido Univ., Fac.of Adv.Life Sci., Prof., 大学院先端生命科学研究院, 教授 (70188704)
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| Project Period (FY) |
2004 – 2006
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| Keywords | innate immune system / protein / conformational analysis / peptide / invertebrate |
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| Research Abstract |
Growth-blocking peptide (GBP) is a small insect cytokine with various activities: larval growth regulation, cell proliferation, and stimulation of a class of lepidopteran insect blood cells (plasmatocytes). GBP was initially identified as a 25 amino acid peptide hormone (1-25 GBP), which suppress the growth of host armyworm, found in the hemolymph of the parasitized armyworm. However, in non-parasitized armyworm larvae, 23 amino acid GBP is expressed in insect plasma. Subsequent studies revealed that the parasitization by wasp induced an elongation of the C-terminal amino acid sequence of GBP (1-28 GBP). In this study, we characterized the GBP analogs, which consist of various length of C-terminal region, by comparison of their biological activities and three-dimensional structures. The results indicate that 1-28 GBP exhibits the strongest activity to suppress the larval growth. NMR analysis shows that these peptides have the same tertiary structures basically, ^-which consist of a dis
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ordered N-terminal region, a structured core stabilized by a disulfide bond and an antiparallel β-sheet in aqueous solution. However, the C-terminal region of 1-28 GBP undergoes conformational transition from a random-coiled state to an a-helical state in the presence of dodecylphosphocholine (DPC) micelles. It suggests that the C-terminal region bound to membrane would have an affects on the larval growth activity.
We isolated, identified, and determined the solution structure of a novel peptide from lepidopteran, Pseudaletia separata that induces rapid hemocyte aggregation. The isolated peptide from crude integument extract, designated hemocyte-aggregation factor (AGF), was revealed to contain 32 amino acid residues (H_2N-SVQILRCPDGMQMLRSGQCVATTEPPFDPDSY-COOH) by N-terminal amino acid sequencing and 3'-RACE. NMR spectra of ^<15>N-labelled AGF were recorded at 283-313 K and pH 5.0. The full sequential assignment for all non-proline residues was achieved using ^<15>N-edited TOCSY and NOESY spectra. The solution structure was calculated by CYANA and discussed in relevance to the functional feature of AGF. Less
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