| Co-Investigator(Kenkyū-buntansha) |
F. HERBST ビオテク研究所, 所長
W.G. FORSSMA ニーダーザクセン州立ペプチド研究所, 所長, 教授
VICTOR WRAY 国立バイオテクノロジー研究所(GBF), 主任研究員
NOKIHARA Kiyoshi Biotechnology Instruments Department, Shimadzu Corp., バイオ機器部, 課長 (60137073)
OZAKI Tsutosi National Institute for Physiological Sciences, 生理学研究所, 助教授 (20045694)
KUWAHARA Atsukazu National Institute for Physiological Sciences, 生理学研究所, 助手 (60142890)
SEO Yositeru National Institute for Physiological Sciences, 生理学研究所, 助手 (90179317)
FURUYA Sonoko National Institute for Physiological Sciences, 生理学研究所, 助手 (20096952)
HERBST Franz Biotek
FORSSMANN W.G. Niedersachsisches Institute fur Peptid-Forschung
WRAY Victor Gesellschaft fur Biotechnologische Forschung
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| Research Abstract |
In order to understand the molecular recognition of pituitary adenylate cyclase activating polypeptide (PACAP), a new vasoactive intestinal polypeptide (VIP) like neuropeptide, by its receptors and possible physiological function in cardiovascular control, the structure and activity relationship was investigated. PACAP and their related peptides were synthesized by the Fmoc strategy using a solid phase peptide synthesizer. Solution structures of PACAP38 and PACAP27 were studied in aqueous solution containing varying amounts of trifluoroethanol by circular dichroism spectroscopy and a combination of 2D ^1H nuclear magnetic resonance spectroscopy, distance geometry, and refined molecular dynamics and energy minimization calculations. PACAP38 had an initial disordered N-terminal domain of 8 amino acids, followed by an alpha-helical structure from 9th to 20th, 21st to 26th, and a short alpha-helix between 28th and 34th. The structure of PACAP27 was closely similar to that of PACAP38 but showed no fraying of the C-terminal helix. PACAP38 and PACAP27 had a potent vasodilator action similar to that of VIP in femoral blood flow in dogs and in the isolated quinea pig blood vessels. The effect of PAVAP38 lasted 3-4 times longer that the others. In the digestive system of dogs and quinea pigs, PACAP38 and PACAP27 contracted the gallbladder and stimulated pancreatic fluid, bicarbonate and protein secretion. VIP, on the other hand, relaxed the isolated gall-bladder strips. PACAP acts on the pancreas and gallbladder indirectly via cholinergic nerves in dogs, but its effect in vitro was a direct one These results suggests that vasodilator action of PACAP resides in N-terminal region, where it has high sequence homology with VIP. The C-terminal structure of PACAP38 is important for the duration of effect. The N-terminal PACAP sequence distinct from VIP is responsible for stimulation of cholinergic nerves and gallbladder smooth muscle.
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