Poster Presentation The 42nd Lorne Conference on Protein Structure and Function 2017

Detecting protein crosslinks in your food through mass spectrometry (#214)

Hannah McKerchar 1
  1. School of Biological Sciences, University of Canterbury, Christchurch, New Zealand

During food processing and storage, crosslinks can form between proteins, which profoundly influence the nutritional value and properties of food.  One crosslink that can form with heating and basic pH is lysinoalanine.  This crosslink is interesting because it has been shown to decrease essential amino acid availability (particularly lysine) and protein digestibility, protein quality, mineral bioavailability, and utilization amongst other nutritional and toxicological effects.  Once the lysinoalanine crosslink is formed it can be difficult to remove, surviving acidic conditions of protein hydrolysis.  Proteomic approaches and the evolution of ionization techniques in mass spectrometry have led to the development of a range of methods for studying protein crosslinking.  But, it is not without its difficulties.  The primary hurdle in understanding protein crosslinking is the sequencing of crosslinked peptides, as they produce complex fragmentation patterns in mass spectrometry.  The standard shotgun proteomic methods must be adapted to accommodate a low abundance of crosslinked peptides compared to linear peptides in a protein digest.  As a means of simplifying the complex fragmentation patterns, we propose crosslinking two short peptides via lysinoalanine and characterising the fragmentation pattern of this simple crosslinked unit.  We hope that the characteristic pattern can be used as a diagnostic tool for identifying lysinoalanine crosslinks in larger protein complexes.