New interaction network in endocytosis process discovered
AP180 is a protein involved in endocytosis and in signal transmission between nerve cells. This protein, which largely lacks a three-dimensional structure, has never been fully studied.
AP180 is a protein involved in endocytosis and in signal transmission between nerve cells. This protein, which largely lacks a three-dimensional structure, has never been fully studied.
Cell & Microbiology
20 hours ago
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110
What puts the electronic pep in peptides? A folded structure, according to a new study in the Proceedings of the National Academy of Sciences.
Molecular & Computational biology
22 hours ago
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78
A research team affiliated with UNIST has unveiled biosensor technology that uses light to quickly and accurately detect trace amounts of proteins. This breakthrough has significant implications for preventing the spread ...
Biotechnology
Jul 24, 2024
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1
Each cell in the body has its own unique delivery system that scientists are working on harnessing to move revolutionary biological drugs—molecules like proteins, RNA and combinations of the two—to specific diseased parts ...
Biotechnology
Jul 24, 2024
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34
Cell membranes play a crucial role in maintaining the integrity and functionality of cells. However, the mechanisms by which they perform these roles are not yet fully understood. Scientists from the University of Geneva ...
Cell & Microbiology
Jul 24, 2024
0
28
Proteins (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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