Protein ConformationProteins are comprised of linear strings of amino acids, called polypeptide chains. This linear construct folds during and after synthesis into a 3-dimensional form called its "native conformation." The conformation of a protein determines its biological function in the cell by providing exposed binding sites by which the protein binds to other cell components or structures (like membranes).
Changes in the protein's environment can cause structural changes in the conformation of proteins, thereby changing its function. The native conformation is usually designated as the "alpha" configuration, and functional alternative configurations are designated "beta." A polypeptide chain may spontaneously fold into its alpha configuration, and can spontaneously change to its beta form. But many proteins are assisted in their folding process by specialized proteins called chaperones, or by the enzymes protein disulfide isomerase [PDI] and peptide prolyl cis-tran isomerase [PPI].
Protein functions in the cell require native configurations. Defects in protein folding characterize a number of human genetic disorders. Misfolded proteins can accumulate into plaque-like scales called "beta sheets." These cause disease states such as Alzheimer's and the transmissible spongiform encephalopathies. Other proteins, such as the tubulin dimers of microtubules, spontaneously switch from one conformational state to another as part of their normal functioning.
Web Resources On Protein Conformation
Amino Acids and Backbone Conformation
Protein Folding
Switching of beta- to alpha-tubulin phosphorylation
Book Resources On Protein ConformationIntroduction to Protein Structure by Carl Branden
Protein Stability and Folding: Theory and Practice by Bret A. Shirley
Prediction of Protein Structure and the Principles of Protein Conformation by G.D. Fasman (Ed.)
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