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HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA
APOBEC3G (A3G), an enzyme expressed in primates with the potential to inhibit human immunodeficiency virus type 1 (HIV-1) infectivity, is a single-stranded DNA (ssDNA) deoxycytidine deaminase with two domains, a catalytically active, weakly ssDNA binding C-terminal domain (CTD) and a catalytically in...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946564/ https://www.ncbi.nlm.nih.gov/pubmed/31850845 http://dx.doi.org/10.7554/eLife.52649 |
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author | Morse, Michael Naufer, M Nabuan Feng, Yuqing Chelico, Linda Rouzina, Ioulia Williams, Mark C |
author_facet | Morse, Michael Naufer, M Nabuan Feng, Yuqing Chelico, Linda Rouzina, Ioulia Williams, Mark C |
author_sort | Morse, Michael |
collection | PubMed |
description | APOBEC3G (A3G), an enzyme expressed in primates with the potential to inhibit human immunodeficiency virus type 1 (HIV-1) infectivity, is a single-stranded DNA (ssDNA) deoxycytidine deaminase with two domains, a catalytically active, weakly ssDNA binding C-terminal domain (CTD) and a catalytically inactive, strongly ssDNA binding N-terminal domain (NTD). Using optical tweezers, we measure A3G binding a single, long ssDNA substrate under various applied forces to characterize the binding interaction. A3G binds ssDNA in multiple steps and in two distinct conformations, distinguished by degree of ssDNA contraction. A3G stabilizes formation of ssDNA loops, an ability inhibited by A3G oligomerization. Our data suggests A3G securely binds ssDNA through the NTD, while the CTD samples and potentially deaminates the substrate. Oligomerization of A3G stabilizes ssDNA binding but inhibits the CTD’s search function. These processes explain A3G’s ability to efficiently deaminate numerous sites across a 10,000 base viral genome during the reverse transcription process. |
format | Online Article Text |
id | pubmed-6946564 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-69465642020-01-09 HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA Morse, Michael Naufer, M Nabuan Feng, Yuqing Chelico, Linda Rouzina, Ioulia Williams, Mark C eLife Structural Biology and Molecular Biophysics APOBEC3G (A3G), an enzyme expressed in primates with the potential to inhibit human immunodeficiency virus type 1 (HIV-1) infectivity, is a single-stranded DNA (ssDNA) deoxycytidine deaminase with two domains, a catalytically active, weakly ssDNA binding C-terminal domain (CTD) and a catalytically inactive, strongly ssDNA binding N-terminal domain (NTD). Using optical tweezers, we measure A3G binding a single, long ssDNA substrate under various applied forces to characterize the binding interaction. A3G binds ssDNA in multiple steps and in two distinct conformations, distinguished by degree of ssDNA contraction. A3G stabilizes formation of ssDNA loops, an ability inhibited by A3G oligomerization. Our data suggests A3G securely binds ssDNA through the NTD, while the CTD samples and potentially deaminates the substrate. Oligomerization of A3G stabilizes ssDNA binding but inhibits the CTD’s search function. These processes explain A3G’s ability to efficiently deaminate numerous sites across a 10,000 base viral genome during the reverse transcription process. eLife Sciences Publications, Ltd 2019-12-18 /pmc/articles/PMC6946564/ /pubmed/31850845 http://dx.doi.org/10.7554/eLife.52649 Text en © 2019, Morse et al http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited. |
spellingShingle | Structural Biology and Molecular Biophysics Morse, Michael Naufer, M Nabuan Feng, Yuqing Chelico, Linda Rouzina, Ioulia Williams, Mark C HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA |
title | HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA |
title_full | HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA |
title_fullStr | HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA |
title_full_unstemmed | HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA |
title_short | HIV restriction factor APOBEC3G binds in multiple steps and conformations to search and deaminate single-stranded DNA |
title_sort | hiv restriction factor apobec3g binds in multiple steps and conformations to search and deaminate single-stranded dna |
topic | Structural Biology and Molecular Biophysics |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946564/ https://www.ncbi.nlm.nih.gov/pubmed/31850845 http://dx.doi.org/10.7554/eLife.52649 |
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