Biocurious is a weblog about biology, quantified.

Molecule of the Month: 70S Ribosomes

by PhilipJ on 7 January 2010

Ribosomes are one of the wonders of the cellular world, and one of the many wonders you can explore yourself at the RCSB PDB. In 2000, structural biologists Venkatraman Ramakrishnan, Thomas A. Steitz and Ada E. Yonath made the first structures of ribosomal subunits available in the PDB, and in 2009, they each received a Nobel Prize for this work. Structures are also available for many of the other players in protein synthesis, including transfer RNA and elongation factors. Building on these structures, there are now hundreds of structures of entire ribosomes in the PDB, revealing the atomic details of many important steps in protein synthesis.

After solving the structures of the individual small and large subunits, the next step in ribosome structure research was to determine the structure of the whole ribosome. This work is the culmination of decades of research, which started with blurry pictures of the ribosome from electron microscopy, continued with more detailed cryoelectron micrographic reconstructions, and now includes many atomic structures. By using small pieces of mRNA, various forms of shortened or chemically-modified tRNA, purified protein factors, and modified ribosomes, researchers have solved the structures of ribosomes in the act of building proteins. These structures are so large that they don’t fit into a single PDB file—for instance, the structure shown here was split into PDB entries 2wdk and 2wdl.

Looking at all the different forms of life on the Earth, we find that all living organisms have ribosomes and that they come in two basic sizes. Bacteria and archaebacteria have smaller ribosomes, termed 70S ribosomes, which are composed of a small 30S subunit and large 50S subunit. The “S” stands for svedbergs, a unit used to measure how fast molecules move in a centrifuge (note that the values for the individual subunits don’t add up to the value for the whole ribosome, since the rate of sedimentation is related in a complex way to the mass and shape of the molecule). The ribosomes in our cells, and in other animals, plants and fungi, are larger, termed 80S ribosomes, composed of a 40S small subunit and a 60S large subunit. Strangely, our mitochondria have small 70S ribosomes that are made separately from the larger ones in the cytoplasm. This observation has lead to the hypothesis that mitochondria (and chloroplasts in plant cells) are actually bacteria that were caught inside cells early in the evolution of eukaryotic cells. Now, they live and reproduce happily inside cells, focusing on energy production and relying on the surrounding cell for most of their other needs.

Read more from David Goodsell at the RCSB PDB, here.



  1. tava tea    2609 days ago    #

    As I biology tutor I use the edosymbiotic theory to explain the difference in size between a prokaryotic cell and a eukaryotic cell. Now I have something more to share with my students. Thanks for the post.


  2. gclub    169 days ago    #

    i have been searching for this for so long… now I found it. thanks to your post.

    goldenslot


  3. gclub69    45 days ago    #

    A site that will allow gamblers easily. One of the most popular gambling bets is one. Give more return Gamblers everywhere Gambling sources to help play this way. Do not waste time on the bets. There are bets to like to get more things to help keep the gambler better every day. There are bets that people choose. To gamble every day.

    In addition, it is interesting. It is well known that in the first 6 months, infants should drink milk from their mother’s breast. In addition to nutrients. It also helps to strengthen the development and landscape together as well. I’m not short of troops. I have a warm picture. Breastfeeding The love of concern always sent. Oh tell me that. I usually drink milk until I fall asleep every night.

    There is a gamble to play it fully. There are bets to play well. Have fun every day, like gamblers to play all the time. It is a gambling that will allow playing all areas. There are more bets. Give a good return every day.


  4. mannoi4444    19 days ago    #

    <a href=https://www.gclub69.com/gclub>จีคลับ</a> A site that will allow players to play well. Play gambling as you like. All bets are made for gamblers to enjoy more profits. What kind of gambler can play? Give good money Can play anywhere To play simply One bet Enjoy Allows players to gamble themselves every day. Can play as you like, bets that will yield more.

    In addition, it is interesting with different types of beans. Eating different kinds of nuts do not help the heart. It also helps to reduce abdominal fat as well. Nuts are high protein grains. It stimulates our metabolism to work more diligently. Walnuts contain antioxidants and anti-inflammatory properties in walnuts, which are important to help fight obesity. Help us feel full stomach. We have better food control, conquer the belly to smooth it better.

    It is interesting and there are bets that people choose. Play as you like. Just like gamblers can play all their own. Full bet Can play well to play all types. There is a play that will like to give a good return. There are more and more fun bets on the site. <a href=https://www.gclub69.com/baccarat>บาคาร่า</a>


  5. mannoi    18 days ago    #

    <a href=https://www.gclub69.com/gclub>G club</a> Online gambling game sites that offer a variety of ways to play gamblers. Full on every day bets. To gamble all kinds of casino slots, roulette and gambling games are all good. Make more profits. Play gamblers well, have fun, give players the answer instead of playing as you like. There are bets that will give the player a fun experience. To play well, there are gamblers to choose from. Make more money this way. Have a good bet Gambling is fun. Make more profits. The bet was great fun every day.

    Which bets to give all kinds of. Play yourself at all times. Do not get into the casino, it will be able to gambling well. Simplicity with gamblers to like. Good gambling source. Give the player more items. There are bets that one will experience good gambling everywhere. There is a unique play. Make a bet every day. Just like or would like to gamble. Can join all the great players with a unique play. By the way, gamblers are full of fun every day at the site. <a href=https://www.gclub69.com/gclub>Gclub มือถือ</a>


  6. mannoi    18 days ago    #

    [url=https://www.gclub69.com/gclub]Gclub มือถือ[/url] The site with the gambling game to play the most. It’s a bet that will give you a good return. Can play both girls and boys. There are gamblers who like to play this way. Gamblers are good everywhere. Gambling in the way you like. Who wants to gamble? Can play anywhere Make more money. Just like you can have fun anywhere, every day. There is a smartphone to gamble all good every day. Make good money every day. It will help to gamble itself every day. Like it or make it easy to gamble. Come play anywhere, every day every day.

    Just connecting to the internet can be a good bet. Have a game to play every day. All bets are roulette, roulette, baccarat and other types of gambling games to gamble themselves every day. Simple Wagering There are various gambling techniques that will make for a great profit. Come and play gambling. It will give you a good profit. To gamble every day. Gambling sources that provide liquidity are betting to like. To play well all Make more money. Then it can be a good bet anywhere. There are always good bets with the site. [url=https://www.gclub69.com/gclub]G club[/url]

    Which bets to give all kinds of. Play yourself at all times. Do not get into the casino, it will be able to gambling well. Simplicity with gamblers to like. Good gambling source. Give the player more items. There are bets that one will experience good gambling everywhere. There is a unique play. Make a bet every day. Just like or would like to gamble. Can join all the great players with a unique play. By the way, gamblers are full of fun every day at the site. <a href=https://www.gclub69.com/gclub>Gclub มือถือ</a>


Name
Email
http://
Message
  Textile help