Featured Research

from universities, journals, and other organizations

The Ribosome: Perfectionist Protein-maker Trashes Errors

Date:
January 9, 2009
Source:
Johns Hopkins Medical Institutions
Summary:
The enzyme machine that translates a cell's DNA code into the proteins of life is nothing if not an editorial perfectionist.

The ribosome, a perfectionist protein-maker, in all its majesty. Translation is what the ribosome does: it translates our genetic code to manufacture proteins which, as workhorses of the cell, carry out the business of life.
Credit: Image courtesy of Johns Hopkins Medical Institutions

The enzyme machine that translates a cell's DNA code into the proteins of life is nothing if not an editorial perfectionist.

Related Articles


Johns Hopkins researchers, reporting in the journal Nature January 7, have discovered a new "proofreading step" during which the suite of translational tools called the ribosome recognizes errors, just after making them, and definitively responds by hitting its version of a "delete" button.

It turns out, the Johns Hopkins researchers say, that the ribosome exerts far tighter quality control than anyone ever suspected over its precious protein products which, as workhorses of the cell, carry out the very business of life.

"What we now know is that in the event of miscoding, the ribosome cuts the bond and aborts the protein-in-progress, end of story," says Rachel Green, a Howard Hughes Medical Institute investigator and professor of molecular biology and genetics in the Johns Hopkins University School of Medicine. "There's no second chance." Previously, Green says, molecular biologists thought the ribosome tightly managed its actions only prior to the actual incorporation of the next building block by being super-selective about which chemical ingredients it allows to enter the process.

Because a protein's chemical "shape" dictates its function, mistakes in translating assembly codes can be toxic to cells, resulting in the misfolding of proteins often associated with neurodegenerative conditions. Working with bacterial ribosomes, Green and her team watched them react to lab-induced chemical errors and were surprised to see that the protein-manufacturing process didn't proceed as usual, getting past the error and continuing its "walk" along the DNA's protein-encoding genetic messages.

"We thought that once the mistake was made, it would have just gone on to make the next bond and the next," Green says. "But instead, we noticed that one mistake on the ribosomal assembly line begets another, and it's this compounding of errors that leads to the partially finished protein being tossed into the cellular trash," she adds.

To their further surprise, the ribosome lets go of error-laden proteins 10,000 times faster than it would normally release error-free proteins, a rate of destruction that Green says is "shocking" and reveals just how much of a stickler the ribosome is about high-fidelity protein synthesis.

"These are not subtle numbers," she says, noting that there's a clear biological cost for this ribosomal editing and jettisoning of errors, but a necessary expense.

"The cell is a wasteful system in that it makes something and then says, forget it, throw it out," Green concedes. "But it's evidently worth the waste to increase fidelity. There are places in life where fidelity matters."

The research was funded by the National Institutes of Health with support from the Howard Hughes Medical Institute.

In addition to Rachel Green, Hani S. Zaher, also of Johns Hopkins, was author of the paper.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "The Ribosome: Perfectionist Protein-maker Trashes Errors." ScienceDaily. ScienceDaily, 9 January 2009. <www.sciencedaily.com/releases/2009/01/090107134529.htm>.
Johns Hopkins Medical Institutions. (2009, January 9). The Ribosome: Perfectionist Protein-maker Trashes Errors. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2009/01/090107134529.htm
Johns Hopkins Medical Institutions. "The Ribosome: Perfectionist Protein-maker Trashes Errors." ScienceDaily. www.sciencedaily.com/releases/2009/01/090107134529.htm (accessed October 24, 2014).

Share This



More Plants & Animals News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com
Weird-Looking Dinosaur Solves 50-Year-Old Mystery

Weird-Looking Dinosaur Solves 50-Year-Old Mystery

Newsy (Oct. 23, 2014) You've probably seen some weird-looking dinosaurs, but have you ever seen one this weird? It's worth a look. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins