A picosecond UV laser radiation was used to cross - link proteins to DNA in nuclei, whole cells and different chromatin preparations. All histones as well as high - mobility group 1 proteins were identified immunochemically in the covalently linked protein - DNA complexes. Irradiation of the nucleohistone resulted in cross - linking 20% of bound histones to DNA as a result of two - quantum photoreaction with a maximum quantum yield 3.10-4 for double stranded DNA. When nuclei, total hromatin, H1 - depleted chromatin and core particles were irradiated and then trypsinized or treated with clostripain to cleave respectively the N-, C- and N- terminal histone tails, no histones were found covalently linked to DNA. However whilst the yield of cross - links was similar in total and H1 - depleted chromatin in core particles the efficiency was 3 - 4 times lower for H2A, H2B and H4 and 10 - 12 times lower for H3.
|Number of pages||10|
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|Issue number||pt 1|
|Publication status||Published - 1991|
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Condensed Matter Physics