Título

Substrate-induced dimerization of engineered monomeric variants of triosephosphate isomerase from Trichomonas vaginalis

Autor

SAMUEL LARA GONZALEZ

PEDRO JIMENEZ SANDOVAL

MARISOL LÓPEZ HIDALGO

LAURA MARGARITA LOPEZ CASTILLO

CARLOS HUMBERTO TRASVIÑA ARENAS

MARIA EUGENIA SANCHEZ SANDOVAL

ARMANDO GOMEZ PUYOU

JAIME ORTEGA LOPEZ

CLAUDIA GUADALUPE BENITEZ CARDOZA

Luis Brieba

Nivel de Acceso

Acceso Abierto

Identificador alterno

doi: https://doi.org/10.1371/journal.pone.0141747

Resumen o descripción

"The dimeric nature of triosephosphate isomerases (TIMs) is maintained by an extensive surface area interface of more than 1600 angstrom 2. TIMs from Trichomonas vaginalis (TvTIM) are held in their dimeric state by two mechanisms: a ball and socket interaction of residue 45 of one subunit that fits into the hydrophobic pocket of the complementary subunit and by swapping of loop 3 between subunits. TvTIMs differ from other TIMs in their unfolding energetics. In TvTIMs the energy necessary to unfold a monomer is greater than the energy necessary to dissociate the dimer. Herein we found that the character of residue I45 controls the dimer-monomer equilibrium in TvTIMs. Unfolding experiments employing monomeric and dimeric mutants led us to conclude that dimeric TvTIMs unfold following a four state model denaturation process whereas monomeric TvTIMs follow a three state model. In contrast to other monomeric TIMs, monomeric variants of TvTIM1 are stable and unexpectedly one of them (I45A) is only 29-fold less active than wild-type TvTIM1. The high enzymatic activity of monomeric TvTIMs contrast with the marginal catalytic activity of diverse monomeric TIMs variants. The stability of the monomeric variants of TvTIM1 and the use of cross-linking and analytical ultracentrifugation experiments permit us to understand the differences between the catalytic activities of TvTIMs and other marginally active monomeric TIMs. As TvTIMs do not unfold upon dimer dissociation, herein we found that the high enzymatic activity of monomeric TvTIM variants is explained by the formation of catalytic dimeric competent species assisted by substrate binding."

Editor

Public Library of Science

Fecha de publicación

noviembre de 2015

Tipo de publicación

Artículo

Versión de la publicación

Versión publicada

Formato

application/pdf

Idioma

Inglés

Audiencia

Público en general

Sugerencia de citación

Lara-Gonzalez S, Estrella P, Portillo C, Cruces ME, Jimenez-Sandoval P, Fattori J, et al. (2015) Substrate-Induced Dimerization of Engineered Monomeric Variants of Triosephosphate Isomerase from Trichomonas vaginalis. PLoS ONE 10(11): e0141747. https://doi.org/10.1371/journal.pone.0141747

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