Figure 5.
Effect of domain cross-linking on the flavin fluorescence and CaM response of nNOSr proteins. Left panel, proteins were excited at 457 nm, and their fluorescence emission was monitored at 530 nm over time. Representative emission traces are shown for nNOSr (red) and for the CLSS protein that was DTT-treated (black) or was cross-linked by either a disulfide bond (blue), BMOE (brown), BMH (dark green), BM(PEG)2 (pink), or BM(PEG)3 (green). Ca2+ and EDTA was added at 200 and 400 s, respectively, to induce and reverse CaM binding. Right panel, fluorescence emission gain observed upon CaM binding to the indicated proteins, as derived from the left panel. Maximum cross-link distances are indicated. Data are representative of two experiments.