Fig. 3.

AT adopts trimeric and dodecameric states in solution. (A) ¹H-¹⁵N HSQC NMR spectrum of 1 mM AT, pH 7.5 reveals doubling of many signals; residue assignments as indicated (black, AT₃; red, AT₁₂). (B) Native MS in 100 mM AmAc shows trimers are favored at pH 8 and 12-mers are favored at pH 6; predicted (Zn-AT)₃: 17,144.9 Da; (Zn-AT)₁₂: 68,579.4 Da; observed at pH 6: 17,181.8 ± 63.7 Da and 68,826.5 ± 76.4 Da; observed at pH 8: 17,181.5 ± 55.3 Da and 68,751.5 ± 47.3 Da. Other oligomeric states are not evident. The extra mass can be attributed to salt and/or solvent adducts, typical for the instrument used.