Fig. 2.
Reconstructed ESI-quadrupole mass spectra of A. vinelandii IscU, IscUC37A, IscUC63A, and IscUC106A after incubation with IscS and l-cysteine in the mass range corresponding to a covalent IscS–IscU complex. Samples are the same as those used in the right panel of Fig. 1.