Skip to main content
. Author manuscript; available in PMC: 2020 Mar 5.
Published in final edited form as: Anal Chem. 2019 Feb 12;91(5):3611–3618. doi: 10.1021/acs.analchem.8b05605

Figure 2.

Figure 2

(a) Interface areas of streptavidin tetramer as determined by PISA analysis (1SWB).58 (b) Mass spectrum of streptavidin tetramer under charge reducing conditions. (c) SID spectrum (45 V, 495 eV) of the 11+ tetramer. (d) A zoomed-in segment of (c) at 140,000 resolution setting, revealing the isotope distributions of 3+ monomer and 6+ homodimer. (e) A zoomed in segment of (c) at 17,500 resolution setting, showing non-cleaved N-terminal methionine(s) and sodium adducts on 3+ monomer and 6+ dimer.