Lasers improve scientists’ understanding of complex proteins

Nov 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: 'NanoSuit': Researchers use nano-coating to allow for electron microscopy of living insects

add to favorites email to friend print save as pdf

Related Stories

NHL sends GoPro cameras onto the ice

1 hour ago

Ice hockey fans will get a new perspective on the fast-moving game when National Hockey League players don GoPro cameras, starting with this weekend's all-star fixture.

NASA spacecraft almost to Pluto: Smile for the camera!

1 hour ago

It's showtime for Pluto. NASA's New Horizons spacecraft has traveled 3 billion miles and is nearing the end of its nine-year journey to Pluto. Sunday, it begins photographing the mysterious, unexplored, icy ...

Recommended for you

Holes in valence bands of nanodiamonds discovered

Jan 28, 2015

Nanodiamonds are tiny crystals only a few nanometers in size. While they possess the crystalline structure of diamonds, their properties diverge considerably from those of their big brothers, because their ...

Demystifying nanocrystal solar cells

Jan 28, 2015

ETH researchers have developed a comprehensive model to explain how electrons flow inside new types of solar cells made of tiny crystals. The model allows for a better understanding of such cells and may ...

User comments : 0

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.