Protein folding factor

Most reactions in cells are carried out by enzymes [1], In many instances the rates of enzyme-catalysed reactions are enhanced by a factor of a million. A significantly large fraction of all known enzymes are proteins which are made from twenty naturally occurring amino acids. The amino acids are linked by peptide bonds to fonn polypeptide chains. The primary sequence of a protein specifies the linear order in which the amino acids are linked. To carry out the catalytic activity the linear sequence has to fold to a well defined tliree-dimensional (3D) stmcture. In cells only a relatively small fraction of proteins require assistance from chaperones (helper proteins) [2]. Even in the complicated cellular environment most proteins fold spontaneously upon synthesis. The detennination of the 3D folded stmcture from the one-dimensional primary sequence is the most popular protein folding problem. 

Structural factors are important regarding rational design approaches that lead to predicting stable protein folds. Can anything be learned about protein stability from different structural elements, amino acids, and packing of the native folds... 

Just as the functioning of nucleic acids depends in part on its overall structure, so does the activity of proteins depend on its overall structure. Protein folding is one of the hot areas today in science. To the synthetic polymer chemist, understanding the influences of factors, basic or fundamental, which produce protein chain folding will allow the creation of new synthetic polymers that possess specifically desired properties. For biochemists, understanding these factors allows us to better understand other factors and to combat particular diseases related to chain folding. 

Therefore, de novo designed two-stranded parallel and antiparallel coiled coils become ideal model systems to study the factors that contribute to our understanding of protein folding and assembly. 

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