Related topics: proceedings of the national academy of sciences , cells , genes
Protein
hideProteins (also known as polypeptides) are organic compounds made of amino acids arranged in a linear chain. The amino acids in a polymer chain are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids, however in certain organisms the genetic code can include selenocysteine — and in certain archaea — pyrrolysine. Shortly after or even during synthesis, the residues in a protein are often chemically modified by post-translational modification, which alter the physical and chemical properties, folding, stability, activity, and ultimately, the function of the proteins. Proteins can also work together to achieve a particular function, and they often associate to form stable complexes.
Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms and participate in virtually every process within cells. Many proteins are enzymes that catalyze biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, which form a system of scaffolding that maintains cell shape. Other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. Proteins are also necessary in animals' diets, since animals cannot synthesize all the amino acids they need and must obtain essential amino acids from food. Through the process of digestion, animals break down ingested protein into free amino acids that are then used in metabolism.
Proteins were first described and named by the Swedish chemist Jöns Jakob Berzelius in 1838. However, the central role of proteins in living organisms was not fully appreciated until 1926, when James B. Sumner showed that the enzyme urease was a protein. The first protein to be sequenced was insulin, by Frederick Sanger, who won the Nobel Prize for this achievement in 1958. The first protein structures to be solved were hemoglobin and myoglobin, by Max Perutz and Sir John Cowdery Kendrew, respectively, in 1958. The three-dimensional structures of both proteins were first determined by x-ray diffraction analysis; Perutz and Kendrew shared the 1962 Nobel Prize in Chemistry for these discoveries. Proteins may be purified from other cellular components using a variety of techniques such as ultracentrifugation, precipitation, electrophoresis, and chromatography; the advent of genetic engineering has made possible a number of methods to facilitate purification. Methods commonly used to study protein structure and function include immunohistochemistry, site-directed mutagenesis, and mass spectrometry.
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News tagged with protein
Research sheds light on workings of anti-cancer drug
Chemistry / Analytical Chemistry
11 hours ago |
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(PhysOrg.com) -- The copper sequestering drug tetrathiomolybdate (TM) has been shown in studies to be effective in the treatment of Wilson disease, a disease caused by an overload of copper, and certain metastatic cancers. ...
Crosstalk between critical cell-signaling pathways holds clues to tumor invasion and metastasis
Nov 25, 2009 |
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Two signaling pathways essential to normal human development - the Wnt/Wingless (Wnt) and epidermal growth factor receptor (EGFR) pathways - interact in ways that can promote tumor cell invasion and metastasis, researchers ...
Study sheds light on brain's fear processing center
Nov 25, 2009 |
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Breathing carbon dioxide can trigger panic attacks, but the biological reason for this effect has not been understood. A new study by University of Iowa researchers shows that carbon dioxide increases brain acidity, which ...
Ice Cold: Cooler Than Being Cool
Nov 24, 2009 |
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(PhysOrg.com) -- Water expands when it freezes. Anyone who has ever left a can of soda or bottle of water in the freezer too long has witnessed this first hand. So how do plants and animals survive severe ...
Invention will help speed development of drug treatments for heart failure
Nov 23, 2009 |
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Research conducted by University of Minnesota scientists, in collaboration with Celladon Corporation, has led to the invention of technology to more rapidly identify compounds for the treatment of heart failure.
Computational microscope peers into the working ribosome (w/ Video)
Nov 23, 2009 |
4.9 / 5 (9) |
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Two new studies reveal in unprecedented detail how the ribosome interacts with other molecules to assemble new proteins and guide them toward their destination in biological cells. The studies used molecular ...
Ultrasound enhances noninvasive Down syndrome tests
Nov 20, 2009 |
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The addition of a "genetic sonogram" maximizes the accuracy of non-invasive testing for Down syndrome, said a Baylor College of Medicine researcher who was lead author of a landmark study in the current issue of Obstetrics an ...
Atomic-level Snapshot Catches Protein Motor in Action (w/ Video)
Nov 20, 2009 |
4.7 / 5 (3) |
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(PhysOrg.com) -- The atomic-level action of a remarkable class of ring-shaped protein motors has been uncovered by researchers with the Lawrence Berkeley National Laboratory using a state-of-the-art protein ...
Biologists discover bacterial defense mechanism against aggressive oxygen
Nov 20, 2009 |
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Bacteria possess an ingenious mechanism for preventing oxygen from harming the building blocks of the cell. This is the new finding of a team of biologists that includes Joris Messens of VIB, a life sciences research institute ...
Scientists identify DNA that regulates antibody production
Nov 20, 2009 |
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(PhysOrg.com) -- When foreign invaders trip the immune system’s alarm, antibodies need to be specially sculpted to attack them head on. New research now shows that gene segments called enhancers control the reshuffling of ...
Researchers find new piece of BSE puzzle
Nov 20, 2009 |
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A new treatment route for bovine spongiform encephalopathy (BSE) and its human form Creutzfeldt Jakob disease (CJD) could be a step closer based on new results from scientists at the University of Leeds. The team has found ...
Saving the single cysteine: new antioxidant system found (w/ Video)
Nov 19, 2009 |
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(PhysOrg.com) -- We've all read studies about the health benefits of having a life partner. The same thing is true at the molecular level, where amino acids known as cysteines are much more vulnerable to damage when single ...
Scientists unlock clues for tailoring corn plant for food, energy needs
Nov 19, 2009 |
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(PhysOrg.com) -- Scientists have long known that the offspring of two inbred strains tend to be superior to both their parents. Now, a team of researchers including a University of Florida geneticist has discovered clues ...
Let them eat snail
Nov 19, 2009 |
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A nutritionist in Nigeria says that malnutrition and iron deficiency in schoolchildren could be reduced in her country by baking up snail pie. In a research paper to be published in the International Journal of Food Safety, Nu ...
On the trail of a vaccine for Lyme disease: Researchers target tick saliva
Nov 19, 2009 |
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A protein found in the saliva of ticks helps protect mice from developing Lyme disease, Yale researchers have discovered. The findings, published in the November 19 issue of Cell Host & Microbe, may spur d ...
