¹H, ¹⁵N and ¹³C backbone resonance assignments of the archetypal serpin α₁-antitrypsin

Alpha1-antitrypsin is a 45-kDa (394-residue) serine protease inhibitor synthesized by hepatocytes, which is released into the circulatory system and protects the lung from the actions of neutrophil elastase via a conformational transition within a dynamic inhibitory mechanism. Relatively common point mutations subvert this transition, causing polymerisation of α₁-antitrypsin and deficiency of the circulating protein, predisposing carriers to severe lung and liver disease. We have assigned the backbone resonances of α₁-antitrypsin using multidimensional heteronuclear NMR spectroscopy. These assignments provide the starting point for a detailed solution state characterization of the structural properties of this highly dynamic protein via NMR methods.