Characterization of Band 3 Variant G130R Using Site-Directed Spin Labeling and Electron Paramagnetic Resonance

Abstract

In this thesis, the structural differences between wild-type band 3 and band 3 Fukuoka, the G130R mutant identified in cases of hereditary spherocytosis associated with reduction of protein 4.2, are examined. The G130R mutation occurs on the solvent-facing side of helix 2 on the globular portion of the cytosolic domain of band 3. Site-directed spin labeling coupled with electron paramagnetic resonance techniques are presented as methods for investigating subtle changes to protein structure. While the overall structure of the band 3 dimer shows little change, side chain mobilities are altered on helix 2. Solvent accessibility, on the other hand, shows that helix 2 maintains its backbone structure and relative orientation on the surface of band 3. I believe these small changes to helix 2 affect the binding of band 3 to ankyrin due to the proximity to their interaction site.