Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.

Harakiri is a BH3-only member of the Bcl-2 family that localizes in membranes and induces cell death by binding to prosurvival Bcl-x(L) and Bcl-2. The cytosolic domain of Harakiri is largely disorder with residual α-helical conformation according to previous structural studies. As these helical stru...

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Autores principales:	Susana Barrera-Vilarmau, Patricia Obregón, Eva de Alba
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2011
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/269a779041d143edb52750de91634354
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spelling	oai:doaj.org-article:269a779041d143edb52750de916343542021-11-18T06:51:26ZIntrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.1932-620310.1371/journal.pone.0021413https://doaj.org/article/269a779041d143edb52750de916343542011-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21731739/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203Harakiri is a BH3-only member of the Bcl-2 family that localizes in membranes and induces cell death by binding to prosurvival Bcl-x(L) and Bcl-2. The cytosolic domain of Harakiri is largely disorder with residual α-helical conformation according to previous structural studies. As these helical structures could play an important role in Harakiri's function, we have used NMR and circular dichroism to fully characterize them at the residue-atomic level. In addition, we report structural studies on a peptide fragment spanning Harakiri's C-terminal hydrophobic sequence, which potentially operates as a transmembrane domain. We initially checked by enzyme immunoassays and NMR that peptides encompassing different lengths of the cytosolic domain are functional as they bind Bcl-x(L) and Bcl-2. The structural data in water indicate that the α-helical conformation is restricted to a 25-residue segment comprising the BH3 domain. However, structure calculation was precluded because of insufficient NMR restraints. To bypass this problem we used alcohol-water mixture to increase structure population and confirmed by NMR that the conformation in both milieus is equivalent. The resulting three-dimensional structure closely resembles that of peptides encompassing the BH3 domain of BH3-only members in complex with their prosurvival partners, suggesting that preformed structural elements in the disordered protein are central to binding. In contrast, the transmembrane domain forms in micelles a monomeric α-helix with a population close to 100%. Its three-dimensional structure here reported reveals features that explain its function as membrane anchor. Altogether these results are used to propose a tentative structural model of how Harakiri works.Susana Barrera-VilarmauPatricia ObregónEva de AlbaPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 6, Iss 6, p e21413 (2011)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Susana Barrera-Vilarmau Patricia Obregón Eva de Alba Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
description	Harakiri is a BH3-only member of the Bcl-2 family that localizes in membranes and induces cell death by binding to prosurvival Bcl-x(L) and Bcl-2. The cytosolic domain of Harakiri is largely disorder with residual α-helical conformation according to previous structural studies. As these helical structures could play an important role in Harakiri's function, we have used NMR and circular dichroism to fully characterize them at the residue-atomic level. In addition, we report structural studies on a peptide fragment spanning Harakiri's C-terminal hydrophobic sequence, which potentially operates as a transmembrane domain. We initially checked by enzyme immunoassays and NMR that peptides encompassing different lengths of the cytosolic domain are functional as they bind Bcl-x(L) and Bcl-2. The structural data in water indicate that the α-helical conformation is restricted to a 25-residue segment comprising the BH3 domain. However, structure calculation was precluded because of insufficient NMR restraints. To bypass this problem we used alcohol-water mixture to increase structure population and confirmed by NMR that the conformation in both milieus is equivalent. The resulting three-dimensional structure closely resembles that of peptides encompassing the BH3 domain of BH3-only members in complex with their prosurvival partners, suggesting that preformed structural elements in the disordered protein are central to binding. In contrast, the transmembrane domain forms in micelles a monomeric α-helix with a population close to 100%. Its three-dimensional structure here reported reveals features that explain its function as membrane anchor. Altogether these results are used to propose a tentative structural model of how Harakiri works.
format	article
author	Susana Barrera-Vilarmau Patricia Obregón Eva de Alba
author_facet	Susana Barrera-Vilarmau Patricia Obregón Eva de Alba
author_sort	Susana Barrera-Vilarmau
title	Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
title_short	Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
title_full	Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
title_fullStr	Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
title_full_unstemmed	Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
title_sort	intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.
publisher	Public Library of Science (PLoS)
publishDate	2011
url	https://doaj.org/article/269a779041d143edb52750de91634354
work_keys_str_mv	AT susanabarreravilarmau intrinsicorderanddisorderinthebcl2memberharakiriinsightsintoitsproapoptoticactivity AT patriciaobregon intrinsicorderanddisorderinthebcl2memberharakiriinsightsintoitsproapoptoticactivity AT evadealba intrinsicorderanddisorderinthebcl2memberharakiriinsightsintoitsproapoptoticactivity
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Intrinsic order and disorder in the bcl-2 member harakiri: insights into its proapoptotic activity.

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