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Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization
Serpins are protease inhibitors whose most stable state is achieved upon transition of a central 5-stranded β-sheet to a 6-stranded form. Mutations, low pH, denaturants and elevated temperatures promote this transition, which can result in a growing polymer chain of inactive molecules. Different typ...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Portland Press Ltd.
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4080824/ https://www.ncbi.nlm.nih.gov/pubmed/24552432 http://dx.doi.org/10.1042/BJ20131650 |
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author | Irving, James A. Haq, Imran Dickens, Jennifer A. Faull, Sarah V. Lomas, David A. |
author_facet | Irving, James A. Haq, Imran Dickens, Jennifer A. Faull, Sarah V. Lomas, David A. |
author_sort | Irving, James A. |
collection | PubMed |
description | Serpins are protease inhibitors whose most stable state is achieved upon transition of a central 5-stranded β-sheet to a 6-stranded form. Mutations, low pH, denaturants and elevated temperatures promote this transition, which can result in a growing polymer chain of inactive molecules. Different types of polymer are possible, but, experimentally only heat has been shown to generate polymers in vitro consistent with ex vivo pathological specimens. Many mutations that alter the rate of heat-induced polymerization have been described, but interpretation is problematic because discrimination is lacking between the effect of global changes in native stability and specific effects on structural mechanism. We show that the temperature midpoint (T(m)) of thermal denaturation reflects the transition of α(1)-antitrypsin to the polymerization intermediate, and determine the relationship with fixed-temperature polymerization half-times (t(0.5)) in the presence of stabilizing additives [TMAO (trimethylamine N-oxide), sucrose and sodium sulfate], point mutations and disulfide bonds. Combined with a retrospective analysis of 31 mutants characterized in the literature, the results of the present study show that global changes to native state stability are the predominant basis for the effects of mutations and osmolytes on heat-induced polymerization, summarized by the equation: ln(t(0.5,mutant)/t(0.5,wild-type))=0.34×ΔT(m). It is deviations from this relationship that hold key information about the polymerization process. |
format | Online Article Text |
id | pubmed-4080824 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Portland Press Ltd. |
record_format | MEDLINE/PubMed |
spelling | pubmed-40808242014-07-18 Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization Irving, James A. Haq, Imran Dickens, Jennifer A. Faull, Sarah V. Lomas, David A. Biochem J Research Article Serpins are protease inhibitors whose most stable state is achieved upon transition of a central 5-stranded β-sheet to a 6-stranded form. Mutations, low pH, denaturants and elevated temperatures promote this transition, which can result in a growing polymer chain of inactive molecules. Different types of polymer are possible, but, experimentally only heat has been shown to generate polymers in vitro consistent with ex vivo pathological specimens. Many mutations that alter the rate of heat-induced polymerization have been described, but interpretation is problematic because discrimination is lacking between the effect of global changes in native stability and specific effects on structural mechanism. We show that the temperature midpoint (T(m)) of thermal denaturation reflects the transition of α(1)-antitrypsin to the polymerization intermediate, and determine the relationship with fixed-temperature polymerization half-times (t(0.5)) in the presence of stabilizing additives [TMAO (trimethylamine N-oxide), sucrose and sodium sulfate], point mutations and disulfide bonds. Combined with a retrospective analysis of 31 mutants characterized in the literature, the results of the present study show that global changes to native state stability are the predominant basis for the effects of mutations and osmolytes on heat-induced polymerization, summarized by the equation: ln(t(0.5,mutant)/t(0.5,wild-type))=0.34×ΔT(m). It is deviations from this relationship that hold key information about the polymerization process. Portland Press Ltd. 2014-04-25 2014-05-15 /pmc/articles/PMC4080824/ /pubmed/24552432 http://dx.doi.org/10.1042/BJ20131650 Text en © 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC-BY)(http://creativecommons.org/licenses/by/3.0/) which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. http://creativecommons.org/licenses/by/3.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Article Irving, James A. Haq, Imran Dickens, Jennifer A. Faull, Sarah V. Lomas, David A. Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
title | Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
title_full | Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
title_fullStr | Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
title_full_unstemmed | Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
title_short | Altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
title_sort | altered native stability is the dominant basis for susceptibility of α(1)-antitrypsin mutants to polymerization |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4080824/ https://www.ncbi.nlm.nih.gov/pubmed/24552432 http://dx.doi.org/10.1042/BJ20131650 |
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