The Open Natural Products Journal

2011, 4 : 16-20
Published online 2011 April 27. DOI: 10.2174/1874848101104010016
Publisher ID: TONPJ-4-16

Theoretical Investigation of the Structural Properties of Two Crotamines Isolated from the Venom of

Antônio Flávio de C. Alcântara , Dorila Piló-Veloso , Antônio José do N. Fernandes and Maria C. Dos-Santos
Departamento de Química, ICEx, Universidade Federal de Minas Gerais, 31160-901, Belo Horizonte – MG, Brazil.

ABSTRACT

Crotamines 1 and 2 differ only at residue 19 (which is Leu in 1, and Ile in 2), but 1 presents a greater myonecrotic activity. PM3 geometry optimizations of fragments of 1 (I17-C18-L19-P20-P21) and 2 (I17-C18-I19-P20-P21) yielded the minimum energy conformations I-a and II-a, respectively. The HF and DFT calculation of chemical properties (atomic charge, orbital population, and MO energy) of I-a and II-a did not reveal significant differences that would explain the differences in biological activities of the corresponding crotamines. PM3 optimized geometries of full peptides 1 and 2 presented different globular spatial arrangements when disulfide bonds between cysteine residues were considered. This fact may be related to the difference in biological activities observed for the two crotamines.