The Z mutation alters the global structural dynamics of α1-antitrypsin.
α1-Antitrypsin (α1AT) deficiency, the most common serpinopathy, results in both emphysema and liver disease. Over 90% of all clinical cases of α1AT deficiency are caused by the Z variant in which Glu342, located at the top of s5A, is replaced by a Lys which results in polymerization both in vivo and...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Public Library of Science (PLoS)
2014
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/1441956e44c84a3689847f3755838e6e |
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| Sumario: | α1-Antitrypsin (α1AT) deficiency, the most common serpinopathy, results in both emphysema and liver disease. Over 90% of all clinical cases of α1AT deficiency are caused by the Z variant in which Glu342, located at the top of s5A, is replaced by a Lys which results in polymerization both in vivo and in vitro. The Glu342Lys mutation removes a salt bridge and a hydrogen bond but does not effect the thermodynamic stability of Z α1AT compared to the wild type protein, M α1AT, and so it is unclear why Z α1AT has an increased polymerization propensity. We speculated that the loss of these interactions would make the native state of Z α1AT more dynamic than M α1AT and that this change renders the protein more polymerization prone. We have used hydrogen/deuterium exchange combined with mass spectrometry (HXMS) to determine the structural and dynamic differences between native Z and M α1AT to reveal the molecular basis of Z α1AT polymerization. Our HXMS data shows that the Z mutation significantly perturbs the region around the site of mutation. Strikingly the Z mutation also alters the dynamics of regions distant to the mutation such as the B, D and I helices and specific regions of each β-sheet. These changes in global dynamics may lead to an increase in the likelihood of Z α1AT sampling a polymerogenic structure thereby causing disease. |
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