Fig. 5
nTDMS analysis of 20Z-pMMO in MSP2N2 nanodiscs. a Deconvoluted MS2 showing detection of 20Z-pMMO subunit masses upon ejection from the nanodisc-pMMO complex. The panel on the right contains the theoretical masses of the subunits, accounting for the modifications characterized by tandem MS. b Graphical fragment maps of pMMO subunits derived from the MS3 step in the nTDMS platform. Fragments are depicted as blue flags in the graphical fragment maps, indicating which regions of the protein sequence can be accounted for in mass by the fragments. The pMMO subunits were found to be modified by N-terminal acetylation (PmoA and PmoC), N-terminal truncation (PmoC), and lysine methylation (PmoB). The graphical fragment map of PmoB begins at residue His 33, showing cleavage of the known N-terminal signal peptide
