SERUM FATTY ACIDS IN MULTIPLE SCLEROSIS.

Abstract

<h3>Abstract</h3> Biological polypeptides are known to contain <i>cis</i>-linkage in their main chain as a minor but important feature. Such anomalous connection of amino acids has different structural and functional effects on proteins. Experimental evidence of <i>cis</i>-bonds in proteins is mainly obtained using X-ray crystallography and other methods in the field of structural biology. To date, extensive analyses have been carried out on the experimentally found <i>cis</i>-bonds using the Protein Data Bank entry bases and/or residue bases; however, their consistency in each protein has not been examined on a global scale. Data accumulation and advances in methodology enable the use of new approaches from a proteomic point of view. Here, we sought to describe a simple procedure for the detection and confirmation of <i>cis</i>-bonds from a set of experimental coordinates for a protein to discriminate this type of bond from isomerizable and/or misassigned bonds. The resulting set of consistent <i>cis</i> bonds provides unprecedented insights into the trend of “high <i>cis</i> content” proteins and the upper limit of consistent <i>cis</i> bonds per polypeptide length. Recognizing such limit would not only be important for a practical check of upcoming structures, but also for the design of novel protein folds beyond the evolutionally-acquired repertoire.