Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor

The LDL receptor internalizes circulating LDL and VLDL particles for degradation. Its extracellular binding domain contains ten (seven LA and three EGF) cysteine-rich modules, each bearing three disulfide bonds. Despite the enormous number of disulfide combinations possible, LDLR oxidative folding l...

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Authors: Martínez-Oliván, J., Fraga, H., Arias-Moreno, X., Ventura, S., Sancho, J.
Format: article
Status:Published version
Publication Date:2015
Country:España
Institution:Universidad de Zaragoza
Repository:Zaguán. Repositorio Digital de la Universidad de Zaragoza
OAI Identifier:oai:zaguan.unizar.es:46937
Online Access:http://zaguan.unizar.es/record/46937
Access Level:Open access
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spelling Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptorMartínez-Oliván, J.Fraga, H.Arias-Moreno, X.Ventura, S.Sancho, J.The LDL receptor internalizes circulating LDL and VLDL particles for degradation. Its extracellular binding domain contains ten (seven LA and three EGF) cysteine-rich modules, each bearing three disulfide bonds. Despite the enormous number of disulfide combinations possible, LDLR oxidative folding leads to a single native species with 30 unique intradomain disulfides. Previous folding studies of the LDLR have shown that non native disulfides are initially formed that lead to compact species. Accordingly, the folding of the LDLR has been described as a "coordinated nonvectorial" reaction, and it has been proposed that early compaction funnels the reaction toward the native structure. Here we analyze the oxidative folding of LA4 and LA5, the modules critical for ApoE binding, isolated and in the LA45 tandem. Compared to LA5, LA4 folding is slow and inefficient, resembling that of LA5 disease-linked mutants. Without Ca++, it leads to a mixture of many two-disulfide scrambled species and, with Ca++, to the native form plus two three-disulfide intermediates. The folding of the LA45 tandem seems to recapitulate that of the individual repeats. Importantly, although the folding of the LA45 tandem takes place through formation of scrambled isomers, no interdomain disulfides are detected, i.e. the two adjacent modules fold independently without the assistance of interdomain covalent interactions. Reduction of incredibly large disulfide combinatorial spaces, such as that in the LDLR, by intradomain confinement of disulfide bond formation might be also essential for the efficient folding of other homologous disulfide-rich receptors.2015info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://zaguan.unizar.es/record/46937reponame:Zaguán. Repositorio Digital de la Universidad de Zaragozainstname:Universidad de ZaragozaInglésinfo:eu-repo/grantAgreement/ES/MINECO/BFU2013-47064-Pinfo:eu-repo/grantAgreement/ES/MICINN/BFU2013-44763-Pinfo:eu-repo/grantAgreement/ES/MICINN/BFU2010-14901info:eu-repo/grantAgreement/ES/DGA/PI078-08info:eu-repo/semantics/openAccessoai:zaguan.unizar.es:469372026-05-29T13:59:51Z
dc.title.none.fl_str_mv Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
title Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
spellingShingle Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
Martínez-Oliván, J.
title_short Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
title_full Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
title_fullStr Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
title_full_unstemmed Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
title_sort Intradomain confinement of disulfides in the folding of two consecutive modules of the LDL receptor
dc.creator.none.fl_str_mv Martínez-Oliván, J.
Fraga, H.
Arias-Moreno, X.
Ventura, S.
Sancho, J.
author Martínez-Oliván, J.
author_facet Martínez-Oliván, J.
Fraga, H.
Arias-Moreno, X.
Ventura, S.
Sancho, J.
author_role author
author2 Fraga, H.
Arias-Moreno, X.
Ventura, S.
Sancho, J.
author2_role author
author
author
author
description The LDL receptor internalizes circulating LDL and VLDL particles for degradation. Its extracellular binding domain contains ten (seven LA and three EGF) cysteine-rich modules, each bearing three disulfide bonds. Despite the enormous number of disulfide combinations possible, LDLR oxidative folding leads to a single native species with 30 unique intradomain disulfides. Previous folding studies of the LDLR have shown that non native disulfides are initially formed that lead to compact species. Accordingly, the folding of the LDLR has been described as a "coordinated nonvectorial" reaction, and it has been proposed that early compaction funnels the reaction toward the native structure. Here we analyze the oxidative folding of LA4 and LA5, the modules critical for ApoE binding, isolated and in the LA45 tandem. Compared to LA5, LA4 folding is slow and inefficient, resembling that of LA5 disease-linked mutants. Without Ca++, it leads to a mixture of many two-disulfide scrambled species and, with Ca++, to the native form plus two three-disulfide intermediates. The folding of the LA45 tandem seems to recapitulate that of the individual repeats. Importantly, although the folding of the LA45 tandem takes place through formation of scrambled isomers, no interdomain disulfides are detected, i.e. the two adjacent modules fold independently without the assistance of interdomain covalent interactions. Reduction of incredibly large disulfide combinatorial spaces, such as that in the LDLR, by intradomain confinement of disulfide bond formation might be also essential for the efficient folding of other homologous disulfide-rich receptors.
publishDate 2015
dc.date.none.fl_str_mv 2015
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://zaguan.unizar.es/record/46937
url http://zaguan.unizar.es/record/46937
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv info:eu-repo/grantAgreement/ES/MINECO/BFU2013-47064-P
info:eu-repo/grantAgreement/ES/MICINN/BFU2013-44763-P
info:eu-repo/grantAgreement/ES/MICINN/BFU2010-14901
info:eu-repo/grantAgreement/ES/DGA/PI078-08
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv
publisher.none.fl_str_mv
dc.source.none.fl_str_mv reponame:Zaguán. Repositorio Digital de la Universidad de Zaragoza
instname:Universidad de Zaragoza
instname_str Universidad de Zaragoza
reponame_str Zaguán. Repositorio Digital de la Universidad de Zaragoza
collection Zaguán. Repositorio Digital de la Universidad de Zaragoza
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