In molecular biology protein structure describes the various levels of organization of protein molecules. Proteins are an important class of biological macromolecules present in all organisms. Proteins are polymers of amino acids. Classified by their physical size, proteins are nanoparticles (definition: 1–100 nm). Each protein polymer – also known as a polypeptide – consists of a sequence formed from 20 possible 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 non-covalent interactions such as hydrogen bonding, ionic interactions, Van Der Waals forces, and hydrophobic packing. To understand the functions of proteins at a molecular level, it is often necessary to determine their three-dimensional structure. This is the topic of the scientific field of structural biology, which employs techniques such as X-ray crystallography, NMR spectroscopy, and dual polarisation interferometry to determine the structure of proteins.
Protein structures range in size from tens to several thousand residues Very large aggregates can be formed from protein subunits: for example, many thousand actin molecules assemble into a microfilament.
A protein may undergo reversible structural changes in performing its biological function. The alternative structures of the same protein are referred to as different conformations, and transitions between them are called conformational changes.
Read more about Protein Structure: Domains, Motifs, and Folds in Protein Structure, Protein Folding, Protein Structure Determination, Structure Classification, Computational Prediction of Protein Structure
Other articles related to "protein structure, structure, protein, proteins, protein structures":
... The primary structure (string of amino acids) of a protein ultimately encodes its uniquely folded 3D conformation ... The most important factor governing the folding of a protein into 3D structure is the distribution of polar and non-polar side chains ... Generally proteins have a core of hydrophobic residues surrounded by a shell of hydrophilic residues ...
... The structure of βARK1 consists of a protein of 689 amino acids (79.7 kilodaltons) with a protein kinase catalytic domain that bears greatest sequence similarity to protein kinase C and the ...
... Monte Carlo algorithms for predicting protein structure in the absence of a template, as assessed in the Critical Assessment of Techniques for Protein Structure Prediction (CASP), a contest for which he would soon ... and David Baker, an original and imaginative framework for assisting homology-based modelling of protein structures making use of both empirical knowledge of protein structure ... a program that is now consolidated as one of the references in the field of protein structure alignment ...
... The generation of a protein sequence is much easier than the determination of a protein structure ... However, the structure of a protein gives much more insight in the function of the protein than its sequence ... Therefore, a number of methods for the computational prediction of protein structure from its sequence have been developed ...
Famous quotes containing the words structure and/or protein:
“... the structure of our public morality crashed to earth. Above its grave a tombstone read, Be toleranteven of evil. Logically the next step would be to say to our commonwealths criminals, I disagree that its all right to rob and murder, but naturally I respect your opinion. Tolerance is only complacence when it makes no distinction between right and wrong.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 2, ch. 2 (1962)
“Firm-style bean curd insoles cushion feet, absorb perspiration and provide more protein than meat or fish innersoles of twice the weight. Tofu compresses with use, becoming more pungent and flavorful. May be removed when not in use to dry or marinate. Innersoles are ready to eat after 1,200 miles of wear. Each pair provides adult protein requirement for 2 meals. Insoles are sized large to allow for snacks. Recipe booklet included.”
—Alfred Gingold, U.S. humorist. Items From Our Catalogue, Tofu Innersoles, Avon Books (1982)