Susceptibility to proteolysis of triosephosphate isomerase from two pathogenic parasites: Characterization of an enzyme with an intact and a nicked monomer
Por:
Reyes-Vivas H., Martínez-Martínez E., Mendoza-Hernández G., López-Velázquez G., Pérez-Montfort R., Tuena De Gómez-Puyou M., Gómez-Puyou A.
Publicada:
1 ene 2002
Resumen:
The susceptibility to subtilisin of homodimeric triosephosphate isomerase from Trypanosoma brucei (TbTIM) and Trypanosoma cruzi (TcTIM) was studied. Their amino sequence and 3D structure are markedly similar. In 36 h of incubation at a molar ratio of 4 TIM per subtilisin, TcTIM underwent extensive hydrolysis, loss of activity, and large structural alterations. Under the same conditions, only about 50% of the monomers of TbTIM were cleaved in two sites. The higher sensitivity of TcTIM to subtilisin is probably due to a higher intrinsic flexibility. We isolated and characterized TbTIM that had been exposed to subtilisin. It exhibited the molecular mass of the dimer, albeit it was formed by one intact and one nicked monomer. Its kcat with glyceraldehyde 3-phosphate was half that of native TbTIM, with no change in Km. The intrinsic fluorescence of nicked TbTIM was red-shifted by 5 nm. The association between subunits was not affected. The TbTIM data suggest that there are structural differences in the two monomers or that alterations of one subunit change the characteristics of the other subunit. In comparison to the action of subtilisin on TIMs from other species, the trypanosomal enzymes appear to be unique. © 2002 Wiley-Liss, Inc.
Filiaciones:
Reyes-Vivas H.:
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Mexico
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70243, 04510 Mexico, Mexico
Martínez-Martínez E.:
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Mexico
Mendoza-Hernández G.:
Facultad de Medicina, Universidad Nacional Autónoma de México, México, Mexico
López-Velázquez G.:
Laboratorio de Bioquímica-Genética, Instituto Nacional de Pediatría, Mexico, Mexico
Pérez-Montfort R.:
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Mexico
Tuena De Gómez-Puyou M.:
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Mexico
Gómez-Puyou A.:
Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Mexico
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