Lasers improve scientists’ understanding of complex proteins

November 14, 2005
Lasers improve scientists’ understanding of complex proteins

By shooting lasers at an RNA polymerase (RNAP) and a strand of DNA, scientists have learned a critical component of how a complex protein develops.
Using a system called fluorescence resonance energy transfer (FRET) on a single molecule, a researcher at the Lawrence Livermore National Laboratory’s Physical Biosciences Institute (PBI) in collaboration with UCLA scientists found that the procedure that regulates genes in a strand of DNA is a single process.

Image: A transcribing T7 RNA polymerase initiation complex. (BioInfo Bank)

Earlier studies done with less precision resulted in scientists believing that the beginning and end phases of RNAP copying a DNA strand into RNA were two different processes.

Using FRET, however, the recent study suggests that “there is no mechanistic difference between the start and finish,” said Ted Laurence of Livermore’s PBI.

RNAP is the molecular machine that serves as a gene transcription tool. When it attaches to a strand of DNA, RNAP transcribes genes to RNA, which then is translated into a protein.

FRET allows scientists to measure distances between two single molecules – a donor and an acceptor – using fluorescence. Molecules have to be less than 8-10 nanometers apart for a FRET to occur.

Using a laser process called ALEX (alternating laser excitation), developed by Laurence, the team looked into the energy transfer of a donor molecule on an RNAP to an acceptor molecule on a strand of DNA.

This was the first time a scientific team was able to confirm that the transcription initiation factor remains on an RNAP throughout the transcription process.

“Because this happens all in one phase, it may be that transcription is regulated even after starting,” Laurence said.

The research appears in the Nov. 11 issue of the journal Molecular Cell.

Source: Lawrence Livermore National Laboratory

Explore further: Physicists tease out twisted torques of DNA

Related Stories

Physicists tease out twisted torques of DNA

June 28, 2013

Like an impossibly twisted telephone cord, DNA, the molecule that encodes genetic information, also often finds itself twisted into coils. This twisting, called supercoiling, is caused by enzymes that travel along DNA's helical ...

Backtracking on DNA

June 23, 2009

(PhysOrg.com) -- Accuracy is essential for life, so in converting the information stored in DNA into a form in which it can be used, a high level of precision is required. Dr Tanniemola Liverpool from the Department of Mathematics, ...

Physics of gene transcription unveiled

May 14, 2010

(PhysOrg.com) -- A research team has made precise measurements of where and how RNA polymerase encounters obstacles while it reads nucleosomal DNA.

Recommended for you

Cells lacking nuclei struggle to move in 3-D environments

January 20, 2018

University of North Carolina Lineberger Comprehensive Cancer Center researchers have revealed new details of how the physical properties of the nucleus influence how cells can move around different environments - such as ...

Information engine operates with nearly perfect efficiency

January 19, 2018

Physicists have experimentally demonstrated an information engine—a device that converts information into work—with an efficiency that exceeds the conventional second law of thermodynamics. Instead, the engine's efficiency ...

Team takes a deep look at memristors

January 19, 2018

In the race to build a computer that mimics the massive computational power of the human brain, researchers are increasingly turning to memristors, which can vary their electrical resistance based on the memory of past activity. ...

Fast computer control for molecular machines

January 19, 2018

Scientists at the Technical University of Munich (TUM) have developed a novel electric propulsion technology for nanorobots. It allows molecular machines to move a hundred thousand times faster than with the biochemical processes ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.