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Topic: Ribosome

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In the News (Wed 19 Jun 19)

  Ribosome - Wikipedia, the free encyclopedia
A ribosome is an organelle composed of ribosomal RNA and ribosomal proteins known as a Ribonucleoproteinor RNP.
Ribosomes were first observed in the mid-1950s by Romanian-born American cell biologist George Palade in the electron microscope as dense particles or granules.
The ribosome uses tRNA (transfer RNAs which are RNA molecules that carry an amino acid and present the matching anti-codon, according to the genetic code, to the ribosome) which matches the current codon (triplet) on the mRNA to append an amino acid to the polypeptide chain.
en.wikipedia.org /wiki/Ribosome   (1173 words)

Ribosomes are found in the cytosol (the internal fluid of the cell) of all cells.
Free ribosomes usually produce proteins that are used in the cytosol or in the organelle they occur in.
The ribosome uses tRNA[transfer RNAs are RNA molecules that carry an amino acid and present the matching codon, according to the genetic code, to the ribosome.] which matches the current triplet on the mRNA to append an amino acid to the polypeptide chain.
www.ebroadcast.com.au /lookup/encyclopedia/ri/Ribosome.html   (432 words)

 The Ribosome
The ribosome continues to read the code from the 5' to the 3' and amino acids are added to the growing peptide chain.
Note that the ribosomes are still connected to one another outside the rough endoplasmic reticulum by the mRNA which runs between the large and small subunits.
Recall that the outside membrane of the nuclear envelope is studded with ribosomes and is part of the rough endoplasmic reticulum.
cellbio.utmb.edu /cellbio/ribosome.htm   (1144 words)

A ribosomes is a large molecular complex (organelle), composed of several proteins and ribonucleic acid that reads messenger RNA and thereby synthesizes proteins.
Ribosomes are organelles, or distinct parts of the cell with specific jobs, that are composed of ribosomal RNA (rRNA) and ribosomal proteins.
Free ribosomes float freely in the cell cytoplasm; membrane-bound ribosomes bind to the endoplasmic reticulum or the nuclear membrane.
www.iscid.org /encyclopedia/Ribosome   (250 words)

Ribosomes occur both as free particles within cells and as particles attached to the membranes of the endoplasmic reticulum.
Ribosomes are very numerous in a cell and account for a large proportion of its total nucleic acid.
One ribosome can add between 3 and 5 amino acids to the protein it is growing every second.
www.historyoftheuniverse.com /ribosome.html   (290 words)

 Antibiotic-Resistant Ribosome Sheds Light on Protein Synthesis
Ribosomes are the organelles in living cells responsible for translating the genetic code into proteins.
Ribosomes from this organism should provide the best means for determining the atomic-resolution structure of the ribosome in all stages of protein synthesis.
Streptomycin binds to ribosomes and leads to error-prone protein synthesis, but streptomycin resistance mutations in the ribosome are able to counteract the error-inducing effects of the antibiotic.
www-als.lbl.gov /als/science/sci_archive/68ecoli_ribosome.html   (910 words)

 Highest-Resolution Ribosome Structure
Ribosomes Ready for Extreme Close-Up In 1999, the first structure of the intact ribosome—a very large, asymmetric protein that is difficult to crystallize—was solved by x-ray crystallography at the ALS (see "Solving the Ribosome Puzzle").
The ribosome is a multicomponent machine that, in bacteria, is 21 nm in diameter.
Now that intact ribosome crystals that diffract x rays to high resolution have been obtained, the researchers are now working to probe the structural basis for how these antibiotics work.
www-als.lbl.gov /als/science/sci_archive/125ribosome.html   (949 words)

 Wikinfo | Ribosome
In cell biology, a ribosome is an organelle composed of RNA and ribosomal proteins; which translates mRNA into a polypeptide chain (e.g., a protein).
They insert the freshly produced polypeptide chains directly into the ER, from where they are transported to their destinations Bound ribosomes usually produce proteins that are used within the cell membrane or are expelled from the cell via exocytosis.
The ribosome uses tRNA[transfer RNAs are RNA molecules that carry an amino acid and present the matching codon, according to the genetic code, to the ribosome.]
www.wikinfo.org /wiki.php?title=Ribosome   (518 words)

 biology - Ribosome
A ribosome is an organelle composed of rRNA (synthesized in the nucleolus) and ribosomal proteins.
Ribosomes can float freely in the cytoplasm (the internal fluid of the cell) or bind to another organelle called the endoplasmic reticulum.
Since ribosomes are ribozymes, it is thought that they might be remnants of the RNA world.
www.biologydaily.com /biology/Ribosome   (566 words)

 Los Alamos National Laboratory (LANL): Largest computational biology simulation mimics life's most essential nanomachine
Ribosomes are a fundamental model for future nano-machines, producing the protein building blocks of all living tissue.
The ribosome is the ancient molecular factory responsible for synthesizing proteins in all organisms.
In developing the project, the team identified a corridor inside the ribosome that the transfer RNA must pass through for the decoding to occur, and it appears to be constructed almost entirely of universal bases, implying that it is evolutionarily ancient.
www.lanl.gov /news/index.php?fuseaction=home.story&story_id=7428   (1236 words)

 Structure Of The Ribosome Described In Full Detail
Ribosomes are the protein factories of all living cells.
The central role of RNA in the function of the ribosome is an idea long championed by Noller and others, but only recently confirmed by a series of landmark studies by Noller's group at UC Santa Cruz and by other researchers, including Peter Moore and Thomas Steitz of Yale University.
In their new paper, the three-dimensional structure of the ribosome is revealed in much finer detail, enabling them to identify specific components that carry out key functions.
unisci.com /stories/20011/0330014.htm   (810 words)

 11.03.2005 - New X-rays of cell's ribosome could lead to better antibiotics
The new, high-resolution data on the intact ribosome allows researchers to build more detailed and more realistic models of the ribosome that until now were impossible with the "fuzzy pictures" available.
Ribosomes are dispersed in the hundreds of thousands throughout the cell, and in some highly active cells, ribosomes are responsible for producing millions of proteins per minute.
Ribosomes are found in all organisms, ranging from bacteria to humans, and probably arose nearly 2 billion years ago.
www.berkeley.edu /news/media/releases/2005/11/03_xr.shtml   (1218 words)

 Baserga Lab Publications: Ribosome biogenesis: of knobs and RNA processing.
The synthesis of ribosomes in eukaryotes involves processing of pre-ribosomal RNA (pre-rRNA) and sequential assembly of a large number of ribosomal proteins on the rRNAs.
In this mini-review, we summarize some of the discoveries that have been made in the field of ribosome biogenesis in the past 30 years and highlight some key aspects about what remains to be learned.
A nucleolar protein related to ribosomal protein L7 is required for an early step in large ribosomal subunit biogenesis.
info.med.yale.edu /mbb/baserga/2004/05/ribosome-biogenesis-of-knobs-and-rna.html   (288 words)

 A High-Resolution Solution of the Ribosome Structure
The ribosome is the large molecular machine in all cells that makes proteins (the building blocks of organisms) by translating the information encoded by genes.
Once the tRNA is accepted, the ribosome catalyzes the formation of a peptide bond between the growing protein chain and the new amino acid, lengthening it by one.
Bacteria and human ribosomes are different and as a result, a large number of antibiotics have evolved naturally that bind to and block bacterial ribosomes more effectively than they do human ribosomes.
www.aps.anl.gov /Science/Highlights/2001/ribsome.htm   (775 words)

 Ribosome   (Site not responding. Last check: 2007-10-22)
The prokaryotic ribosome consists of a large 50S subunit and a small 30S subunit both of which are masterpieces of RNA and protein structural architecture.
The large subunit of the prokaryotic ribosome is composed of 2 ribonucleic acid chains (23S rRNA and 5S rRNA) and 31 proteins.
The small ribosomal subunit is a complex of 16S rRNA and 20 proteins which form a structure somewhat more flexible than the 50S subunit.
www.stanford.edu /~magg/ass1/ribosome.html   (256 words)

 Rib-X Pharmaceuticals, Intro to the Ribosome   (Site not responding. Last check: 2007-10-22)
We are designing antibiotics to inhibit ribosome function and block protein synthesis, thereby killing and/or preventing the growth of the bacterial cell.
The ribosome is comprised of 3 RNAs: the 23S, the 16S and the 5S ribosomal RNAs.
Ribosomes translate the information in the genetic code (where nucleotides are one set of letters and words in the mRNA) into the code of proteins (where amino acids make up a second set of letters and words).
www.rib-x.com /about.the.ribosome.html   (510 words)

 Tour of the 70S Ribosome by Wayne Decatur
When a ribosome is in the process of protein translation, another amino acid is added to the end of a growing polypeptide chain.
This is because it is possible to place most individual components at the proper location in the ribosome due to the availibility of other higher resolution structures (2,3,4,5,6).
The original impetus for designing chime-based images of the ribosome was to accompany a series of presentations given in the Fall 2000 Molecular Biology Journal Club at the University of Massachusetts at Amherst.
www.umass.edu /molvis/decatur/my_molecules/pipes/rtour_pipe   (874 words)

 Ribosome   (Site not responding. Last check: 2007-10-22)
Ribosomes consist of two subunits that fit together and work as one to translate the mRNA into a polypeptide chain during protein synthesis.
Ribosomes can be found free floating in the cytoplasm or attached to endoplasmic reticulum.
The ribosome assembles the proper sequence of amino acids to build the protein.
www-personal.umd.umich.edu /~nbhooi/ribosome.htm   (108 words)

 The Molecular Perspective: The Ribosome -- Goodsell 5 (6): 508 -- The Oncologist
The ribosome is composed of two subunits, which clamp around a messenger RNA during protein synthesis.
Ribosomes are composed primarily of RNA, shown here in orange and yellow, decorated by a collection of small proteins, shown in blue.
The ribosome structures are taken from entries 1ffk and 1fka and the peptidase is from entry 1cef at the Protein Data Bank (http://www.rcsb.org/pdb).
theoncologist.alphamedpress.org /cgi/content/full/5/6/508   (633 words)

 Baserga Lab Publications: The small-subunit processome is a ribosome assembly intermediate.
The small-subunit processome is a ribosome assembly intermediate.
These ribosomal proteins may be analogous to the primary or secondary RNA binding proteins first described in bacterial in vitro ribosome assembly maps.
In addition to the ribosomal proteins and based on the same experimental approach, we found seven other proteins (Utp18, Noc4, Utp20, Utp21, Utp22, Emg1, and Krr1) to be bona fide SSU processome proteins.
info.med.yale.edu /mbb/baserga/2004/12/small-subunit-processome-is-ribosome.html   (334 words)

 HHMI News: High-Resolution Image Illuminates Catalytic Engine of the Ribosome
The studies illuminate the basic structure of the ribosome, a protein-making machine found in all cells.
The ribosome is a large molecular complex of RNA and protein.
When ribosomes are isolated from cell extracts, two different fractions are obtained, representing two subunits.
www.hhmi.org /news/steitz.html   (995 words)

 UCSC Biomedical Research - Prof. Harry Noller
The ribosome is therefore a type of readout device, not unlike a tape player.
Ribosomes are among the most complex molecular assemblies in the cell.
An increased understanding of how the ribosome works, together with knowledge of its three-dimensional molecular structure, are now leading to strategies for the design of novel antibiotics.
biomedical.ucsc.edu /Noller.html   (582 words)

 Science@Berkeley Lab: Ratcheting, Swiveling, Opening the Groove
The structure reveals how the ribosome "head" moves while making proteins specified by messenger RNA (mRNA), shuttling transfer RNAs (tRNAs) from site A to site P to site E. Ribosomes are unusual cellular machines in that they are not made mostly of proteins; instead, two-thirds of the ribosome consists of a special form of RNA.
Detailed structures of the ribosome's two main components have been created in recent years, but these are a little like having the plans for two halves of a car without knowing how they fit together.
Since the ribosome's own RNA is infused with magnesium ions and is highly charged, the salt water may act as a kind of "lubricant," locally neutralizing the charge between the subunits to allow them to move in relation to each other and allow tRNAs to slide through the gap.
www.lbl.gov /Science-Articles/Archive/sabl/2005/November/ribosome-groove.html   (1738 words)

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