Structure of methylamine-induced human α2-macroglobulin (hα2M)

α2-Macroglobulin (α2M) is a universal tetrameric suicide inhibitor of 720 kDa that engulfs proteinases after cleavage in a bait region, which triggers major rearrangement from an open, native to a closed, induced form. We purified human α2M (hα2M) from blood and unveiled the different stages of the inhibitory process in the form of the native unbound form, two induced peptidase-bound forms, and several intermediate states. This has allowed us to determine the sequence of events underlying the unique subjacent “Venus flytrap” mechanism. To this aim, we also employed data collected at ESRF C01 under proposal MX-2154. These results have just been accepted for publication. Here, we apply for new time to collect data on methylamine-activated hα2M to compare the structure of this chemically-induced variant with that of the peptidase-induced ones.