Substrate specificity and the effect of calcium on Trypanosomabrucei metacaspase 2

Autor(es)

Machado, Mauricio F. M. ^[1] ; Marcondes, Marcelo F. ^[1] ; Juliano, Maria A. ^[1] ; McLuskey, Karen ^[2] ; Mottram, Jeremy C. ^[2] ; Moss, Catherine X. ^[2] ; Juliano, Luiz ^[1] ; Oliveira, Vitor ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo, Dept Biophys, Escola Paulista Med, BR-04039032 Sao Paulo - Brazil

^[2] Univ Glasgow, Wellcome Trust Ctr Mol Parasitol, Inst Infect Immun & Inflammat, Coll Med Vet & Life Sci, Glasgow G12 8QQ, Lanark - Scotland

• Tipo de documento: Artigo Científico
• Fonte: FEBS Journal; v. 280, n. 11, p. 2608-2621, JUN 2013.
• Citações Web of Science: 10

Resumo

Metacaspases are cysteine peptidases found only in yeast, plants and lower eukaryotes, including the protozoa. To investigate the extended substrate specificity and effects of Ca2+ on the activation of these enzymes, detailed kinetic, biochemical and structural analyses were carried out on metacaspase 2 from Trypanosomabrucei (TbMCA2). These results reveal that TbMCA2 has an unambiguous preference for basic amino acids at the P1 position of peptide substrates and that this is most probably a result of hydrogen bonding from the P1 residue to Asp95 and Asp211 in TbMCA2. In addition, TbMCA2 also has a preference for charged residues at the P2 and P3 positions and for small residues at the prime side of a peptide substrate. Studies into the effects of Ca2+ on the enzyme revealed the presence of two Ca2+ binding sites and a reversible structural modification of the enzyme upon Ca2+ binding. In addition, the concentration of Ca2+ used for activation of TbMCA2 was found to produce a differential effect on the activity of TbMCA2, but only when a series of peptides that differed in P2 were examined, suggesting that Ca2+ activation of TbMCA2 has a structural effect on the enzyme in the vicinity of the S2 binding pocket. Collectively, these data give new insights into the substrate specificity and Ca2+ activation of TbMCA2. This provides important functional details and leads to a better understanding of metacaspases, which are known to play an important role in trypanosomes and make attractive drug targets due to their absence in humans. (AU)

• Processo FAPESP: 11/51718-3 - Incorporação sítio específica de aminoácidos não naturais para o estudo de mudanças conformacionais em proteínas
• Beneficiário: Vitor Marcelo Silveira Bueno Brandão de Oliveira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 08/57336-2 - Obtenção e caracterização das metacaspases: participação destas enzimas na morte celular
• Beneficiário: Mauricio Ferreira Marcondes Machado
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado