Cargando…
Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase
TWINKLE is the helicase involved in replication and maintenance of mitochondrial DNA (mtDNA) in mammalian cells. Structurally, TWINKLE is closely related to the bacteriophage T7 gp4 protein and comprises a helicase and primase domain joined by a flexible linker region. Mutations in and around this l...
Autores principales: | , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423418/ https://www.ncbi.nlm.nih.gov/pubmed/30496414 http://dx.doi.org/10.1093/hmg/ddy415 |
_version_ | 1783404525780992000 |
---|---|
author | Peter, Bradley Farge, Geraldine Pardo-Hernandez, Carlos Tångefjord, Stefan Falkenberg, Maria |
author_facet | Peter, Bradley Farge, Geraldine Pardo-Hernandez, Carlos Tångefjord, Stefan Falkenberg, Maria |
author_sort | Peter, Bradley |
collection | PubMed |
description | TWINKLE is the helicase involved in replication and maintenance of mitochondrial DNA (mtDNA) in mammalian cells. Structurally, TWINKLE is closely related to the bacteriophage T7 gp4 protein and comprises a helicase and primase domain joined by a flexible linker region. Mutations in and around this linker region are responsible for autosomal dominant progressive external ophthalmoplegia (adPEO), a neuromuscular disorder associated with deletions in mtDNA. The underlying molecular basis of adPEO-causing mutations remains unclear, but defects in TWINKLE oligomerization are thought to play a major role. In this study, we have characterized these disease variants by single-particle electron microscopy and can link the diminished activities of the TWINKLE variants to altered oligomeric properties. Our results suggest that the mutations can be divided into those that (i) destroy the flexibility of the linker region, (ii) inhibit ring closure and (iii) change the number of subunits within a helicase ring. Furthermore, we demonstrate that wild-type TWINKLE undergoes large-scale conformational changes upon nucleoside triphosphate binding and that this ability is lost in the disease-causing variants. This represents a substantial advancement in the understanding of the molecular basis of adPEO and related pathologies and may aid in the development of future therapeutic strategies. |
format | Online Article Text |
id | pubmed-6423418 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-64234182019-03-22 Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase Peter, Bradley Farge, Geraldine Pardo-Hernandez, Carlos Tångefjord, Stefan Falkenberg, Maria Hum Mol Genet General Article TWINKLE is the helicase involved in replication and maintenance of mitochondrial DNA (mtDNA) in mammalian cells. Structurally, TWINKLE is closely related to the bacteriophage T7 gp4 protein and comprises a helicase and primase domain joined by a flexible linker region. Mutations in and around this linker region are responsible for autosomal dominant progressive external ophthalmoplegia (adPEO), a neuromuscular disorder associated with deletions in mtDNA. The underlying molecular basis of adPEO-causing mutations remains unclear, but defects in TWINKLE oligomerization are thought to play a major role. In this study, we have characterized these disease variants by single-particle electron microscopy and can link the diminished activities of the TWINKLE variants to altered oligomeric properties. Our results suggest that the mutations can be divided into those that (i) destroy the flexibility of the linker region, (ii) inhibit ring closure and (iii) change the number of subunits within a helicase ring. Furthermore, we demonstrate that wild-type TWINKLE undergoes large-scale conformational changes upon nucleoside triphosphate binding and that this ability is lost in the disease-causing variants. This represents a substantial advancement in the understanding of the molecular basis of adPEO and related pathologies and may aid in the development of future therapeutic strategies. Oxford University Press 2019-04-01 2018-11-29 /pmc/articles/PMC6423418/ /pubmed/30496414 http://dx.doi.org/10.1093/hmg/ddy415 Text en © The Author(s) 2018. Published by Oxford University Press. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | General Article Peter, Bradley Farge, Geraldine Pardo-Hernandez, Carlos Tångefjord, Stefan Falkenberg, Maria Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase |
title | Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase |
title_full | Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase |
title_fullStr | Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase |
title_full_unstemmed | Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase |
title_short | Structural basis for adPEO-causing mutations in the mitochondrial TWINKLE helicase |
title_sort | structural basis for adpeo-causing mutations in the mitochondrial twinkle helicase |
topic | General Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423418/ https://www.ncbi.nlm.nih.gov/pubmed/30496414 http://dx.doi.org/10.1093/hmg/ddy415 |
work_keys_str_mv | AT peterbradley structuralbasisforadpeocausingmutationsinthemitochondrialtwinklehelicase AT fargegeraldine structuralbasisforadpeocausingmutationsinthemitochondrialtwinklehelicase AT pardohernandezcarlos structuralbasisforadpeocausingmutationsinthemitochondrialtwinklehelicase AT tangefjordstefan structuralbasisforadpeocausingmutationsinthemitochondrialtwinklehelicase AT falkenbergmaria structuralbasisforadpeocausingmutationsinthemitochondrialtwinklehelicase |