Cyclic analogs of insect oostatic peptides: synthesis, biological activity, and NMR study.
Cyclic peptides 2a-2c, derived from the sequence of the C-terminal shortened analogs of the oostatic decapeptide H-Tyr-Asp-Pro-Ala-Pro-Pro-Pro-Pro-Pro-Pro-OH (1a), were synthesized and assayed on their effect in a reproduction of the flesh fly Neobellieria bullata. The cyclization of the N-terminal linear tetra- and pentapeptides 1b and 1c to the cyclotetra- and cyclopentapeptides 2b and 2c decreased the oostatic activity by one order of magnitude. The cyclodecapeptide 2a, which emerged spontaneously during the pentapeptide cyclization, was quite inactive. Comparative 1H and 13C NMR study on a conformation of the cyclopeptides 2a-2c, and their linear precursors 1b and 1c revealed that a space structure of the cyclic analogues 2b and 2c is too restricted to adopt a biological conformation necessary for receptor binding and therefore only minor oostatic activity is observed after their application. The lack of the oostatic activity in the case of the more flexible dimeric analogue 2a is ascribed to the size of its molecule and its overall shape that is not compatible with a receptor binding.
Hlavácek
J
J
Institute of Organic Chemistry and Biochemistry, Academy of Sciences, 166 10, Prague 6, Czech Republic.
Budesińský
M
M
Bennettová
B
B
Marík
J
J
Tykva
R
R
D000818:Animals; D001681:Biological Assay; D002247:Carbon Isotopes; D004175:Diptera / Q000187:drug effects* / Q000502:physiology; D005260:Female; D019476:Insect Proteins / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D011522:Protons
D002247:Carbon Isotopes; D019476:Insect Proteins; D009842:Oligopeptides; D010456:Peptides, Cyclic; D011522:Protons; C506017:cyclo(tyrosyl-aspartyl-prolyl-alanine); C506020:cyclo(tyrosyl-aspartyl-prolyl-alanyl-proline); C506021:cyclo(tyrosyl-aspartyl-prolyl-alanyl-tyrosyl-aspartyl-prolyl-alanyl-proline)