Possible cause of male infertility linked to structural protein

Mature spermatozoa are characterized by a head, midpiece and a long tail for locomotion. Now, researchers from the University Hospital Bonn (UKB) and the Transdisciplinary Research Unit "Life & Health" at the University of ...

Study discovers ferns can produce crop-saving insecticide

A new study has identified novel insecticidal proteins in ferns. Professor Marilyn Anderson at La Trobe University said the discovery could lead to plant-made protein pest control for crop plants that are essential to global ...

Revealing structural secrets of a key cancer protein

Scientists have breathed new life into the study of a protein with an outsized link to human cancers because of its dangerous mutations, using advanced research techniques to detect its hidden regions.

Shining light on the radical production of DNA building blocks

Despite its fundamental role in biology and extensive studies over half a century, many aspects of how DNA's building blocks are formed remain unclear. Now, an international team of scientists has revealed valuable details ...

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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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