The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.

<h4>Background</h4>The regulatory subunit (R) of cAMP-dependent protein kinase (PKA) is a modular flexible protein that responds with large conformational changes to the binding of the effector cAMP. Considering its highly dynamic nature, the protein is rather stable. We studied the ther...

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Autores principales:	Khanh K Dao, Angel L Pey, Anja Underhaug Gjerde, Knut Teigen, In-Ja L Byeon, Stein O Døskeland, Angela M Gronenborn, Aurora Martinez
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2011
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/31c7d72bd67e4781abe6317a5e2de01e
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spelling	oai:doaj.org-article:31c7d72bd67e4781abe6317a5e2de01e2021-11-18T06:57:46ZThe regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.1932-620310.1371/journal.pone.0017602https://doaj.org/article/31c7d72bd67e4781abe6317a5e2de01e2011-03-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21394209/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203<h4>Background</h4>The regulatory subunit (R) of cAMP-dependent protein kinase (PKA) is a modular flexible protein that responds with large conformational changes to the binding of the effector cAMP. Considering its highly dynamic nature, the protein is rather stable. We studied the thermal denaturation of full-length RIα and a truncated RIα(92-381) that contains the tandem cyclic nucleotide binding (CNB) domains A and B.<h4>Methodology/principal findings</h4>As revealed by circular dichroism (CD) and differential scanning calorimetry, both RIα proteins contain significant residual structure in the heat-denatured state. As evidenced by CD, the predominantly α-helical spectrum at 25°C with double negative peaks at 209 and 222 nm changes to a spectrum with a single negative peak at 212-216 nm, characteristic of β-structure. A similar α→β transition occurs at higher temperature in the presence of cAMP. Thioflavin T fluorescence and atomic force microscopy studies support the notion that the structural transition is associated with cross-β-intermolecular aggregation and formation of non-fibrillar oligomers.<h4>Conclusions/significance</h4>Thermal denaturation of RIα leads to partial loss of native packing with exposure of aggregation-prone motifs, such as the B' helices in the phosphate-binding cassettes of both CNB domains. The topology of the β-sandwiches in these domains favors inter-molecular β-aggregation, which is suppressed in the ligand-bound states of RIα under physiological conditions. Moreover, our results reveal that the CNB domains persist as structural cores through heat-denaturation.Khanh K DaoAngel L PeyAnja Underhaug GjerdeKnut TeigenIn-Ja L ByeonStein O DøskelandAngela M GronenbornAurora MartinezPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 6, Iss 3, p e17602 (2011)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Khanh K Dao Angel L Pey Anja Underhaug Gjerde Knut Teigen In-Ja L Byeon Stein O Døskeland Angela M Gronenborn Aurora Martinez The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.
description	<h4>Background</h4>The regulatory subunit (R) of cAMP-dependent protein kinase (PKA) is a modular flexible protein that responds with large conformational changes to the binding of the effector cAMP. Considering its highly dynamic nature, the protein is rather stable. We studied the thermal denaturation of full-length RIα and a truncated RIα(92-381) that contains the tandem cyclic nucleotide binding (CNB) domains A and B.<h4>Methodology/principal findings</h4>As revealed by circular dichroism (CD) and differential scanning calorimetry, both RIα proteins contain significant residual structure in the heat-denatured state. As evidenced by CD, the predominantly α-helical spectrum at 25°C with double negative peaks at 209 and 222 nm changes to a spectrum with a single negative peak at 212-216 nm, characteristic of β-structure. A similar α→β transition occurs at higher temperature in the presence of cAMP. Thioflavin T fluorescence and atomic force microscopy studies support the notion that the structural transition is associated with cross-β-intermolecular aggregation and formation of non-fibrillar oligomers.<h4>Conclusions/significance</h4>Thermal denaturation of RIα leads to partial loss of native packing with exposure of aggregation-prone motifs, such as the B' helices in the phosphate-binding cassettes of both CNB domains. The topology of the β-sandwiches in these domains favors inter-molecular β-aggregation, which is suppressed in the ligand-bound states of RIα under physiological conditions. Moreover, our results reveal that the CNB domains persist as structural cores through heat-denaturation.
format	article
author	Khanh K Dao Angel L Pey Anja Underhaug Gjerde Knut Teigen In-Ja L Byeon Stein O Døskeland Angela M Gronenborn Aurora Martinez
author_facet	Khanh K Dao Angel L Pey Anja Underhaug Gjerde Knut Teigen In-Ja L Byeon Stein O Døskeland Angela M Gronenborn Aurora Martinez
author_sort	Khanh K Dao
title	The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.
title_short	The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.
title_full	The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.
title_fullStr	The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.
title_full_unstemmed	The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.
title_sort	regulatory subunit of pka-i remains partially structured and undergoes β-aggregation upon thermal denaturation.
publisher	Public Library of Science (PLoS)
publishDate	2011
url	https://doaj.org/article/31c7d72bd67e4781abe6317a5e2de01e
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The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation.

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