Featured Research

from universities, journals, and other organizations

New Insight Into Architecture Of Cellular Protein Factories: Efficient Working In Confined Spaces

Date:
January 28, 2009
Source:
Max Planck Institute of Biochemistry
Summary:
Each cell in an organism possesses its own protein factories known as ribosomes. Every second, these enzyme complexes produce new proteins with messenger molecules (mRNA) from the cell nucleus as blueprints. In order to generate as many proteins as possible at the same time, several ribosomes cluster together to form an “industrial complex” – the polysome - and read simultaneously the same messenger molecule. Scientists have now, for the first time, been able to reveal the three-dimensional structure of these complexes.

The three dimensional structure of the polysome: Cryoelectron tomographic picture of two polysomes (left), schematic diagram of their structure (middle) and the messenger molecule (mRNA) pathway within the polysome (right). The small ribosomal subunits (yellow) are oriented towards the inside of the polysome, the large subunits (blue) and the nascent protein chains (indicated by red cones) face the cytosol. If the ribosomes are continuously arranged in a “top-to-top” orientation (Fig. A, middle), the result is a pseudo-helical structure of the polysome. If the ribosomes are arranged alternating in “top-to-top” and in “top-to-bottom” orientation (Fig. B, middle), the result is a staggered structure. In both cases the mRNA traverses the shortest possible path from one ribosome to its next neighbor (Fig A and B, right).
Credit: Image courtesy of Max Planck Institute of Biochemistry

Each cell in an organism possesses its own protein factories known as ribosomes. Every second, these enzyme complexes produce new proteins with messenger molecules (mRNA) from the cell nucleus as blueprints. In order to generate as many proteins as possible at the same time, several ribosomes cluster together to form an “industrial complex” – the polysome - and read simultaneously the same messenger molecule.

Scientists at the Max-Planck-Institute of Biochemistry have now, for the first time, been able to reveal the three-dimensional structure of these complexes.

In a polysome, the ribosomes are densely packed and exhibit preferred orientations: The small ribosomal subunits are orientated towards the inside of the polysome and the ribosomes are arranged either in a staggered or in a pseudo-helical structure. This arrangement ensures that the distance between nascent protein chains is maximized, thereby reducing the probability of intermolecular interactions that would give rise to aggregation and limit productive folding. Until now, the belief has been that specialised proteins, the so-called chaperones, would prevent protein misfolding.

Against the background of the new findings, their function appears in a new light: “It appears possible that the main function of chaperones that interact with nascent polypeptide chains is not to suppress chain aggregation within polysomes, but rather to reduce intra-chain misfolding as well as aggregation between different polysomes in the crowded cellular environment”, explains Ulrich Hartl, head of the “Cellular Biochemistry” department, who lead the project in cooperation with Wolfgang Baumeister, head of the “Molecular Structural Biology” department.

Moreover, the spatial structure of the polysome enables the ribosomes to process the messenger molecule in the protected area within the polysome and to pass it on without detours. Thus, the architecture of the cellular protein factories facilitates an optimized work flow and increases the efficiency of protein folding.


Story Source:

The above story is based on materials provided by Max Planck Institute of Biochemistry. Note: Materials may be edited for content and length.


Journal Reference:

  1. Florian Brandt, Adrian H. Elcock, Stephanie A. Etchells, Julio O. Ortiz, F.-Ulrich Hartl and Wolfgang Baumeister. The Native 3D Organization of Bacterial Polysomes. Cell, 23th January 2009 DOI: 10.1016/j.cell.2008.11.016

Cite This Page:

Max Planck Institute of Biochemistry. "New Insight Into Architecture Of Cellular Protein Factories: Efficient Working In Confined Spaces." ScienceDaily. ScienceDaily, 28 January 2009. <www.sciencedaily.com/releases/2009/01/090122120941.htm>.
Max Planck Institute of Biochemistry. (2009, January 28). New Insight Into Architecture Of Cellular Protein Factories: Efficient Working In Confined Spaces. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2009/01/090122120941.htm
Max Planck Institute of Biochemistry. "New Insight Into Architecture Of Cellular Protein Factories: Efficient Working In Confined Spaces." ScienceDaily. www.sciencedaily.com/releases/2009/01/090122120941.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
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