From molecule to medicine via machine learning

It typically takes many years of experiments to develop a new medicine. Although vaccines to protect against disease from the novel coronavirus are starting to reach clinics around the world, patients and doctors will still ...

A genetic shortcut to help visualize proteins at work

One of biologists' most vexing tasks is figuring out how proteins, the molecules that carry the brunt of a cell's work, do their job. Each protein has a variety of knobs, folds, and clefts on its surface that dictate what ...

Heating proteins to understand how genes work

Understanding how genes work and how they interact with one another is a major goal of biology. This poses huge challenges in terms of both methods and the sheer numbers of experiments required. Recent advances have transformed ...

A recipe for protein footprinting

Michael Gross, professor of chemistry in Arts & Sciences at Washington University in St. Louis and of immunology and internal medicine at the School of Medicine, and his team are experts in footprinting proteins—that is, ...

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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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