Health

Plant-based diet protects from hypertension, preeclampsia

A plant-based diet appears to afford significant protection to rats bred to become hypertensive on a high-salt diet, scientists report. When the rats become pregnant, the whole grain diet also protects the mothers and their ...

Medical research

Harmful protein waste in the muscle

An international team of researchers led by the University of Bonn has identified the cause of a rare, severe muscle disease. According to these findings, a single spontaneously occurring mutation results in the muscle cells ...

Diseases, Conditions, Syndromes

Does a plant-based diet really help beat COVID-19?

Since the beginning of the pandemic, it's been suggested that certain foods or diets may offer protection against COVID-19. But are these sorts of claims reliable?

Alzheimer's disease & dementia

What happens in brain cells affected by Alzheimer's disease?

Affecting over 50 million people, Alzheimer's disease is the most common form of dementia and primarily occurs in people over the age of 65. The pathology of the disease in the brain is mainly characterized by two factors: ...

Diseases, Conditions, Syndromes

Study reports compound blocks SARS-CoV-2 and protects lung cells

Research conducted at LSU Health New Orleans Neuroscience Center of Excellence reports that Elovanoids, bioactive chemical messengers made from omega-3 very-long-chain polyunsaturated fatty acids discovered by the Bazan lab ...

Oncology & Cancer

LIM domain only 1: One gene, many roles in cancer

Humans have long been plagued by a myriad of deadly cancers. Parallelly, they attempted different permutations and combinations of treatments to cure the disease. Attempts involving biomolecular targets have come to the fore ...

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Protein

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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