Structure and conformational stability of the triosephosphate isomerase from Zea mays. Comparison with the chemical unfolding pathways of other eukaryotic TIMs
Por:
Romero-Romero S., Becerril-Sesín L.A., Costas M., Rodríguez-Romero A., Fernández-Velasco D.A.
Publicada:
15 nov 2018
Resumen:
We studied the structure, function and thermodynamic properties for the
unfolding of the Triosephosphate isomerase (TIM) from Zea mays (ZmTIM).
ZmTIM shows a catalytic efficiency close to the diffusion limit. Native
ZmTIM is a dimer that dissociates upon dilution into inactive and
unfolded monomers. Its thermal unfolding is irreversible with a T-m of
61.6 +/- 1.4 degrees C and an activation energy of 383.4 +/- 11.5 kJ
mol(-1). The urea-induced unfolding of ZmTIM is reversible. Transitions
followed by catalytic activity and spectroscopic properties are
monophasic and superimposable, indicating that ZmTIM unfolds/refolds in
a two-state behavior with an unfolding Delta G((H20)) = 99.8 +/- 5.3 kJ
mol(-1). This contrasts with most other studied TIMs, where folding
intermediates are common. The three-dimensional structure of ZmTIM was
solved at 1.8 angstrom. A structural comparison with other eukaryotic
TIMs shows a similar number of intramolecular and intermolecular
interactions. Interestingly the number of interfacial water molecules
found in ZmTIM is lower than those observed in most TIMs that show
folding intermediates. Although with the available data, there is no
clear correlation between structural properties and the number of
equilibrium intermediates in the unfolding of TIM, the identification of
such structural properties should increase our understanding of folding
mechanisms.
Filiaciones:
Romero-Romero S.:
Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria04510, Mexico
Becerril-Sesín L.A.:
Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria04510, Mexico
Costas M.:
Laboratorio de Biofisicoquímica, Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria04510, Mexico
Rodríguez-Romero A.:
Laboratorio de Química de Biomacromoléculas 3, Departamento de Química de Biomacromoléculas, Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria04510, Mexico
Fernández-Velasco D.A.:
Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria04510, Mexico
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