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Proceedings of the 31 st European Peptide SymposiumMichal Lebl, Morten Meldal, Knud J. Jensen, Thomas Hoeg-Jensen (Editors)European Peptide Society, 2010Oostatic Peptides Containing D-Amino Acids: Degradation,Accumulation in Ovaries and NMR StudyJan Hlaváček 1 , Blanka Bennettová 2 , Bohuslav Černý 3 ,Věra Vlasáková 4 , Josef Holík 4 , Miloš Buděšínský 1 , Jiřina Slaninová 1 ,and Richard Tykva 11 Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague,166 10, Czech Republic; 2 Institute of Entomology, Czech Academy of Sciences, ČeskéBudějovice, 37 005, Czech Republic; 3 1 st Medical Faculty, Charles University, Prague, 11636, Czech Republic; 4 Institute of Experimental Botany, Czech Academy of Sciences,Prague, 142 20, Czech RepublicIntroductionOostatic pentapeptide H-Tyr-Asp-Pro-Ala-Pro-OH (5P) (1a) is the C-terminus shortenedanalog of decapeptide H-Tyr-Asp-Pro-Ala-Pro-Pro-Pro-Pro-Pro-Pro-OH from mosquitoAedes aegypti [1]. This pentapeptide inhibits a development of eggs in the flesh flyNeobellieria bullata [2] by decreasing their hatchability. In this study, we focused ourinterest on the oostatic activity of analogs of the pentapeptide 1a, containing correspondingD-amino acids: H-D-Tyr-Asp-Pro-Ala-Pro-OH (1b), H-Tyr-D-Asp-Pro-Ala-Pro-OH (1c),H-Tyr-Asp-D-Pro-Ala-Pro-OH (1d), H-Tyr-Asp-Pro-D-Ala-Pro-OH (1e), H-Tyr-Asp-Pro-Ala-D-Pro-OH (1f), all D-(H-Tyr-Asp-Pro-Ala-Pro-OH) (1g) and on accumulation ofradioactivity from tritium labeled pentapeptides H-Tyr-Asp- [ 3 H]Pro-Ala-Pro-OH (2a), H-Tyr-D-Asp-[ 3 H]Pro-Ala-Pro-OH (2b) and H-Tyr-Asp-[ 3 H]Pro-D-Ala Pro-OH (2c) inovaries of N. bullata, and on the labeled pentapeptides degradation [3,4].Results and DiscussionPeptide sequences were assembled on 2-chlorotrityl polystyrene resin, compatible withC-terminal Pro residue, using Fmoc/OtBu strategy. Fmoc deprotection was performed by20% piperidine in DMF and a coupling by DIC/HOBt in DMF. The peptide detachmentfrom the resin and the side-chain deprotection were carried out simultaneously by aTFA/TIS (10:1) mixture for 30 min. Radiolabeled peptides were obtained by addition oftritium gas to the double bond of Δ Pro residue in corresponding precursors, in the presenceof PdO/BaSO 4 .Assay on the oostatic activity of the pentapeptides 1b-1g in the flesh fly N. bullata hasshown a significant decrease of hatchability in the 1st gonotrophic cycle, comparable withthe parent pentapeptide 1a, and no hatchability in the 2nd gonotrophic cycle. Morphologychanges in ovaries correspond to a large resorption of oocytes of treated flies afterapplication of the pentapeptides 1b, 1c and 1g. Even if the pentapeptides 1d-1f exhibit lowFig. 1. Radioactivity of N.bullata ovaries (in kBq) after incubation with pentapeptides 2a -2c. Small means 5th-6th and big means 11th-12th of the 14 developmental stages, based onthe deposition of the yolk in oocytes [5].590