Homology-modelled structure of the βB2B3-crystallin heterodimer studied by ion mobility and radical probe MS

Ion mobility MS was employed to study the structure of the beta B2B3-crystallin heterodimer following its detection by ESI-TOF MS. The results demonstrate that the heterodimer has a similar cross-section (3 165 angstrom(2)) and structure to the beta B2B2-crystallin homodimer. Several homology-modelled structures for the beta B2B3 heterodimer were constructed and assessed in terms of their calculated collision cross-sections and whether the solvent accessibilities of reactive amino acid side chains throughout the beta B3 subunit are in accord with measured oxidation levels in radical probe MS protein footprinting experiments. The beta B2B3 heterodimer AD model provides the best representation of the heterodimer's structure overall following a consideration of both the ion mobility and radical probe MS data.