Human membrane proteins strike evolutionary balance

Cells are compartmentalized by membranes, and proteins present in these membranes play an important role in transporting cellular information. For proper function of these proteins to occur, a tertiary protein structure must ...

Function follows form in plant immunity

Scientists from the Max Planck Institute for Plant Breeding Research (MPIPZ) and the University of Cologne, Germany, have discovered a novel biochemical mechanism explaining how immune proteins defend plants against invading ...

Unlocking complex workings of the biological clock

Scientists want to increase their understanding of circadian rhythms, those internal 24-hour biological clock cycles of sleeping and waking that occur in organisms, ranging from humans to plants to fungi to bacteria. A research ...

New technology solves mystery of respiration in Tetrahymena

Tetrahymena, a tiny single celled-organism, turns out to be hiding a surprising secret: it's doing respiration—using oxygen to generate cellular energy—differently from other organisms such as plants, animals or yeasts. ...

Plant-based steak made from pea protein

ETH Pioneer Fellow Martin Hofmann has developed a method to produce high-quality plant-based meat alternatives. His research on the flow properties of soft materials enables him to imitate the marbling of real steaks.

New advances in protein-folding process thermodynamics

In biophysics, the kinetic states of molecules play a determining role in the metabolic and physiological processes in which they take part. Now, a paper published in the journal Proceedings of the National Academy of Sciences ...

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Protein structure

Proteins are an important class of biological macromolecules present in all biological organisms, made up of such elements as carbon, hydrogen, nitrogen, oxygen, and sulphur. All proteins are polymers of amino acids. The polymers, also known as polypeptides, consist of a sequence of 20 different L-α-amino acids, also referred to as residues. For chains under 40 residues the term peptide is frequently used instead of protein. To be able to perform their biological function, proteins fold into one, or more, specific spatial conformations, driven by a number of noncovalent interactions such as hydrogen bonding, ionic interactions, Van Der Waals forces and hydrophobic packing. In order to understand the functions of proteins at a molecular level, it is often necessary to determine the three dimensional structure of proteins. This is the topic of the scientific field of structural biology, that employs techniques such as X-ray crystallography or NMR spectroscopy, to determine the structure of proteins.

A number of residues are necessary to perform a particular biochemical function, and around 40-50 residues appears to be the lower limit for a functional domain size. Protein sizes range from this lower limit to several thousand residues in multi-functional or structural proteins. However, the current estimate for the average protein length is around 300 residues. Very large aggregates can be formed from protein subunits, for example many thousand actin molecules assemble into a microfilament.

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