Femtosecond Spectroscopy for the Study of Initial Reactions in Protein folding

摘要

In living organisms the genetic information is contained in the DNAand RNA. Here the sequence of the individual base pairs encodes theconstruction of proteins and the regulation of cellular reaction networks.Proteins perform important functions of life such as transcription ofinformation, gene expression, chemical synthesis, energy conversion, andstorage and cellular motion 11. In spite of their multiple tasks, proteins are builtaccording to a unique and simple principle: they consist of a linear chain ofamino acids. Nature uses a set of 20 a-amino acids, differing only in theirspecific side-groups. These side-groups have various chemical properties:hydrophobic to hydrophilic, low to high pKa, inducing local flexibility or localrigidity. The sequence of the amino acids in the protein determines thestructural arrangement of the different groups and thus leads to the overallthree-dimensional structure of its native form and to the specific function of theprotein. During biosynthesis of a protein, the information genetically encoded inthe m-RNA is translated codon by codon to the defined sequence of individualamino acids. Upon the release of the polypeptide chain from the ribosomes itsrearrangement starts.