Molecular machine shuffles beads on a DNA string

April 17, 2003

Yards of DNA are packed into cells by wrapping the DNA around proteins called nucleosomes. But that tight packing makes it hard for the cell's machinery to get at the DNA code to read, copy or repair it. Now researchers at the University of California, Davis, have shown how two proteins form a molecular machine that shuffles the nucleosomes out of the way to expose the DNA double helix.

Postgraduate researchers Andrei Alexeev and Alexander Mazin, with Stephen Kowalczykowski, a professor of microbiology at UC Davis, studied a protein called Rad54 in brewer's yeast (Saccharomyces cerevisiae). Rad54 is known to bind to and change the shape of DNA strands.

Using a piece of DNA with artificial nucleosomes attached, the researchers found that Rad54 could not only move the nucleosomes along the strand but knock them off altogether.

When another protein, Rad51, was added, the process became much more efficient. Rad51 binds to single strands of DNA.

Together, Rad54 and Rad51 form a molecular machine that can carry a piece of DNA to the right place, push the nucleosomes out of the way, expose the DNA double helix and begin the process of stitching a new piece of DNA into place.

The work is published in the March issue of Nature Structural Biology.
-end-


University of California - Davis

Related DNA Articles from Brightsurf:

A new twist on DNA origami
A team* of scientists from ASU and Shanghai Jiao Tong University (SJTU) led by Hao Yan, ASU's Milton Glick Professor in the School of Molecular Sciences, and director of the ASU Biodesign Institute's Center for Molecular Design and Biomimetics, has just announced the creation of a new type of meta-DNA structures that will open up the fields of optoelectronics (including information storage and encryption) as well as synthetic biology.

Solving a DNA mystery
''A watched pot never boils,'' as the saying goes, but that was not the case for UC Santa Barbara researchers watching a ''pot'' of liquids formed from DNA.

Junk DNA might be really, really useful for biocomputing
When you don't understand how things work, it's not unusual to think of them as just plain old junk.

Designing DNA from scratch: Engineering the functions of micrometer-sized DNA droplets
Scientists at Tokyo Institute of Technology (Tokyo Tech) have constructed ''DNA droplets'' comprising designed DNA nanostructures.

Does DNA in the water tell us how many fish are there?
Researchers have developed a new non-invasive method to count individual fish by measuring the concentration of environmental DNA in the water, which could be applied for quantitative monitoring of aquatic ecosystems.

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.

Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.

DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.

A new spin on DNA
For decades, researchers have chased ways to study biological machines.

From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.

Read More: DNA News and DNA Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.