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Título:
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Conformational stability of the NH2-Terminal propeptide of the precursor of pulmonary surfactant protein SP-B
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Autores:
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Bañares Hidalgo, Ángeles ;
Pérez Gil, Jesús ;
Estrada, Pilar
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Tipo de documento:
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texto impreso
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Editorial:
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Plublic Library of Science (PLOS), 2016-07-05
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Dimensiones:
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application/pdf
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Nota general:
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cc_by
info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias Biomédicas: Biología: Bioquímica
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Tipo = Artículo
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Resumen:
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Assembly of pulmonary surfactant lipid-protein complexes depends on conformational changes coupled with proteolytic maturation of proSP-B, the precursor of pulmonary surfactant protein B (SP-B), along the surfactant biogenesis pathway in pneumocytes. Conformational destabilization of the N-terminal propeptide of proSP-B (SP-BN) triggers exposure of the mature SP-B domain for insertion into surfactant lipids. We have studied the conformational stability during GdmCl- or urea-promoted unfolding of SP-BN with trp fluorescence and circular dichroism spectroscopies. Binding of the intermediate states to bis-ANS suggests their molten globule-like character. ?G0 H2O was ~ 12.7 kJ mol-1 either with urea or GdmCl. None of the thermal transitions of SP-BN detected by CD correspond to protein unfolding. Differential scanning calorimetry of SP-BN evidenced two endothermic peaks involved in oligomer dissociation as confirmed with 2 M urea. Ionic strength was relevant since at 150 mM NaCl, the process originating the endotherm at the highest temperature was irreversible (Tm2 = 108.5°C) with an activation energy of 703.8 kJ mol-1. At 500 mM NaCl the process became reversible (Tm2 = 114.4°C) and data were fitted to the Non-two States model with two subpeaks. No free thiols in the propeptide could be titrated by DTNB with or without 5.7 M GdmCl, indicating disulfide bonds establishment.
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En línea:
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https://eprints.ucm.es/43474/1/Conformational%20stability%20of%20the%20NH.pdf
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