Lecture
Reedijk Symposium 2024: Histone HBb: an essential DNA-bending histone in bacteria
- Date
- Friday 22 November 2024
- Time
- Location
-
Lecture Hall
Einsteinweg 57
2333 CC Leiden - Room
- C1
Authors
Samuel Schwab, Yimin Hu, Silvia Deiss, Pedro Escudeiro, Thor van Heesch, Joe Joiner, Jocelyne Vreede, Marcus D. Hartmann, Andrei N. Lupas, Birte Hernandez Alvarez, Vikram Alva, Remus T. Dame
Abstract
Histones are important chromatin-organizing proteins in eukaryotes and archaea. They form superhelical structures around which DNA is wrapped. In contrast, bacteria lack histones and organize their genomes with nucleoid associated proteins, which instead of wrapping DNA generally bend DNA, bridge DNA, and form protein filaments on the DNA. Recently, we identified several potential histones in bacteria, however their DNA-binding characteristics remain unexplored [1]. Here we categorized novel histone HBb from Bdellovibrio bacteriovorus [2]. By determining crystal structures of free and DNA-bound HBb, we unveil its distinctive dimeric assembly, diverging from those of eukaryotic and archaeal histones, while also elucidating how it binds and bends DNA through interaction interfaces reminiscent of eukaryotic and archaeal histones. Building on this, by employing various biophysical and biochemical approaches, we further substantiated the ability of HBb to bind and compact DNA by bending in a sequence-independent manner. Finally, using DNA affinity purification and sequencing, we reveal that HBb binds along the entire genomic DNA of B. bacteriovorus without sequence specificity. These distinct DNA-binding properties of bacterial histones, showcasing remarkable similarities yet significant differences from their archaeal and eukaryotic counterparts, highlight the diverse roles histones play in DNA organization across all domains of life.
References
- Schwab, S., Hu, Y., van Erp, B. et al. Histones and histone variant families in prokaryotes. Nat Commun 15, 7950 (2024). https://doi.org/10.1038/s41467-024-52337-y
- Hu, Y., Schwab, S., Deiss, S. et al. Bacterial histone HBb from Bdellovibrio bacteriovorus compacts DNA by bending. Nucleic acids research, 52(14), 8193–8204 (2024). https://doi.org/10.1093/nar/gkae485