title: Highly potential antiplasmodial restricted peptides.
abstract: Malaria is an infectious disease responsible for approximately one million deaths annually. The antimalarial effects of angiotensin II and its analogs against Plasmodium gallinaceum and P. falciparum have recently been reported. To evaluate antiplasmodial activity, we synthesized five angiotensin II-restricted analogs containing disulfide bridges. To accomplish this, peptides containing two inserted amino acid residues (cysteine) were synthesized by the Fmoc solid-phase method, purified by liquid chromatography, and characterized by mass spectrometry. Conformational studies were performed by circular dichroism. The results indicated that two of the analogs had higher antiplasmodium activity (92% and 98% activity) than angiotensin II (88% activity), measured by fluorescence microscopy. Results showed that the insertion position must be selected, to preserve the hydrophobic interactions between the non-polar residues, as this affects antiplasmodial activity. The circular dichroism studies suggested that the active analogs as well as the native angiotensin II adopt a β-turn conformation in different solutions. This approach provided insight for understanding the effects of restricting the ring size and position on the bioactivity of angiotensin II and provides a new direction for the design of potential chemotherapeutic agents.
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, Brazil.
authors.forename: Torres
authors.initials: T
authors.lastname: Marcelo Der Torossian
authors.forename: Adriana F
authors.initials: AF
authors.lastname: Silva
authors.forename: Flávio L
authors.initials: FL
authors.lastname: Alves
authors.forename: Margareth L
authors.initials: ML
authors.lastname: Capurro
authors.forename: Antonio
authors.initials: A
authors.lastname: Miranda
authors.forename: Oliveira
authors.initials: O
authors.lastname: Vani Xavier
mesh_terms: D000330:Aedes; D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000494:pharmacology*; D002645:Chickens / Q000469:parasitology*; D006801:Humans; D008289:Malaria, Avian / Q000188:drug therapy*; D016778:Malaria, Falciparum / Q000188:drug therapy; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000187:drug effects; D010964:Plasmodium gallinaceum / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D010455:Peptides; D000804:Angiotensin II
keywords: Plasmodium; SAR; angiotensin II; disulfide bridge; malaria