Dissecting DNA-histone interactions in the nucleosome by molecular dynamics simulations of DNA unwrapping
The nucleosome complex of DNA wrapped around a histone protein octamer organizes the genome of eukaryotes and regulates the access of protein factors to the DNA. We performed molecular dynamics simulations of the nucleosome in explicit water to study the dynamics of its histone-DNA interactions. A h...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article (Journal) |
| Language: | English |
| Published: |
12 October 2011
|
| In: |
Biophysical journal
Year: 2011, Volume: 101, Issue: 8, Pages: 1999-2008 |
| ISSN: | 1542-0086 |
| DOI: | 10.1016/j.bpj.2011.07.057 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1016/j.bpj.2011.07.057 Verlag, lizenzpflichtig, Volltext: https://www.sciencedirect.com/science/article/pii/S0006349511010812 
|
| Author Notes: | Ramona Ettig, Nick Kepper, Rene Stehr, Gero Wedemann, and Karsten Rippe |
| Summary: | The nucleosome complex of DNA wrapped around a histone protein octamer organizes the genome of eukaryotes and regulates the access of protein factors to the DNA. We performed molecular dynamics simulations of the nucleosome in explicit water to study the dynamics of its histone-DNA interactions. A high-resolution histone-DNA interaction map was derived that revealed a five-nucleotide periodicity, in which the two DNA strands of the double helix made alternating contacts. On the 100-ns timescale, the histone tails mostly maintained their initial positions relative to the DNA, and the spontaneous unwrapping of DNA was limited to 1-2 basepairs. In steered molecular dynamics simulations, external forces were applied to the linker DNA to investigate the unwrapping pathway of the nucleosomal DNA. In comparison with a nucleosome without the unstructured N-terminal histone tails, the following findings were obtained: 1), Two main barriers during unwrapping were identified at DNA position ±70 and ±45 basepairs relative to the central DNA basepair at the dyad axis. 2), DNA interactions of the histone H3 N-terminus and the histone H2A C-terminus opposed the initiation of unwrapping. 3), The N-terminal tails of H2A, H2B, and H4 counteracted the unwrapping process at later stages and were essential determinants of nucleosome dynamics. Our detailed analysis of DNA-histone interactions revealed molecular mechanisms for modulating access to nucleosomal DNA via conformational rearrangements of its structure. |
|---|---|
| Item Description: | Gesehen am 02.05.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1542-0086 |
| DOI: | 10.1016/j.bpj.2011.07.057 |