Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C

Abstract The hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 °C there are larg...

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Autores principales:	Tiago Veltri, Guilherme A. P. de Oliveira, Ewa A. Bienkiewicz, Fernando L. Palhano, Mayra de A. Marques, Adolfo H. Moraes, Jerson L. Silva, Martha M. Sorenson, Jose R. Pinto
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/24f869ff88314b1487e847a605d31809
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spelling	oai:doaj.org-article:24f869ff88314b1487e847a605d318092021-12-02T12:32:44ZAmide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C10.1038/s41598-017-00777-62045-2322https://doaj.org/article/24f869ff88314b1487e847a605d318092017-04-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-00777-6https://doaj.org/toc/2045-2322Abstract The hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 °C there are large, progressive increases in N-domain Ca2+-binding affinity for D145E but only small changes for the wild-type protein. NMR-derived backbone amide temperature coefficients for many residues show a sharp transition above 30–40 °C, indicating a temperature-dependent conformational change that is most prominent around the mutated EF-hand IV, as well as throughout the C-domain. Smaller, isolated changes occur in the N-domain. Cardiac skinned fibres reconstituted with D145E are more sensitive to Ca2+ than fibres reconstituted with wild-type, and this defect is amplified near body-temperature. We speculate that the D145E mutation destabilises the native conformation of EF-hand IV, leading to a transient unfolding and dissociation of helix H that becomes more prominent at higher temperatures. This creates exposed hydrophobic surfaces that may be capable of binding unnaturally to a variety of targets, possibly including the N-domain of cTnC when it is in its open Ca2+-saturated state. This would constitute a potential route for propagating signals from one end of TnC to the other.Tiago VeltriGuilherme A. P. de OliveiraEwa A. BienkiewiczFernando L. PalhanoMayra de A. MarquesAdolfo H. MoraesJerson L. SilvaMartha M. SorensonJose R. PintoNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-14 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Tiago Veltri Guilherme A. P. de Oliveira Ewa A. Bienkiewicz Fernando L. Palhano Mayra de A. Marques Adolfo H. Moraes Jerson L. Silva Martha M. Sorenson Jose R. Pinto Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C
description	Abstract The hypertrophic cardiomyopathy-associated mutant D145E, in cardiac troponin C (cTnC) C-domain, causes generalised instability at multiple sites in the isolated protein. As a result, structure and function of the mutant are more susceptible to higher temperatures. Above 25 °C there are large, progressive increases in N-domain Ca2+-binding affinity for D145E but only small changes for the wild-type protein. NMR-derived backbone amide temperature coefficients for many residues show a sharp transition above 30–40 °C, indicating a temperature-dependent conformational change that is most prominent around the mutated EF-hand IV, as well as throughout the C-domain. Smaller, isolated changes occur in the N-domain. Cardiac skinned fibres reconstituted with D145E are more sensitive to Ca2+ than fibres reconstituted with wild-type, and this defect is amplified near body-temperature. We speculate that the D145E mutation destabilises the native conformation of EF-hand IV, leading to a transient unfolding and dissociation of helix H that becomes more prominent at higher temperatures. This creates exposed hydrophobic surfaces that may be capable of binding unnaturally to a variety of targets, possibly including the N-domain of cTnC when it is in its open Ca2+-saturated state. This would constitute a potential route for propagating signals from one end of TnC to the other.
format	article
author	Tiago Veltri Guilherme A. P. de Oliveira Ewa A. Bienkiewicz Fernando L. Palhano Mayra de A. Marques Adolfo H. Moraes Jerson L. Silva Martha M. Sorenson Jose R. Pinto
author_facet	Tiago Veltri Guilherme A. P. de Oliveira Ewa A. Bienkiewicz Fernando L. Palhano Mayra de A. Marques Adolfo H. Moraes Jerson L. Silva Martha M. Sorenson Jose R. Pinto
author_sort	Tiago Veltri
title	Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C
title_short	Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C
title_full	Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C
title_fullStr	Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C
title_full_unstemmed	Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C
title_sort	amide hydrogens reveal a temperature-dependent structural transition that enhances site-ii ca2+-binding affinity in a c-domain mutant of cardiac troponin c
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/24f869ff88314b1487e847a605d31809
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Amide hydrogens reveal a temperature-dependent structural transition that enhances site-II Ca2+-binding affinity in a C-domain mutant of cardiac troponin C

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