Heterogeneity in proline hydroxylation of fibrillar collagens observed by mass spectrometry

Collagen is the major protein in extracellular matrix and plays vital roles tissue development function. also one of most processed proteins its biosynthesis. The prominent post-translational modification (PTM) collagen hydroxylation Pro residues Y-position characteristic (Gly-Xaa-Yaa) repeating amino acid sequence a triple helix. Recent studies using mass spectrometry (MS) tandem MS sequencing (MS/MS) have revealed unexpected X-positions (X-Hyp). newly identified X-Hyp appear to be highly heterogeneous location percent occupancy. In order understand dynamic nature new X-Hyps their potential impact on applications MS/MS for research, we sampled four different samples standard techniques. We found considerable variations degree PTMs same from organisms and/or tissues. rat tail tendon type I particularly variable terms both over-hydroxylation X-position under-hydroxylation Y-position. contrast, only few collagens III human placenta were observed. Some observations are not reproducible between efforts sample, presumably due low population unpredictable ionization process. Additionally, despite preparation sourcing, commercial sources do show elevated compared prepared single organism. These findings will contribute growing body information regarding by technology, culminate more comprehensive understanding extent functional collagen.