Stretching DNA-protein complex with optical tweezers permits first direct observation of fundamental genetic packaging unit's dynamic structure
By using optical tweezers to pull individual strands of chromatin -- the DNA-protein complex that chromosomes are made of -- researchers have seen for the first time how information in fundamental genetic packaging units, called nucleosomes, might become accessible to molecules that "read" it.
The report by physicists and biologists at Cornell University and the University of Massachusetts appears in the current Proceedings of the National Academy of Sciences (Vol. 99, Issue 4), "Mechanical Disruption of Individual Nucleosomes Reveals a Reversible Multistage Release of DNA." It marks the first direct observation of the dynamic structure of individual nucleosomes. Chromosomal DNA is packaged into the compact structure of the nuclesome with the help of specialized proteins called histones. The complex of DNA plus histones in cells of higher organisms is called chromatin.
Message posted by: Wouter Kalle