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Figure 6
Laser-activated SSX structures of DtpB. (a)–(e) Omit electron density, contoured at 5σ, maps for NO-bound heme site in chain C of DtpB, collected with different laser energies of 0.81, 8.1, 16.1, 32.2, 64.4 µJ (approximately 0.4, 4, 8, 16, 32 nJ µm−2). With increasing laser power, the electron density maps support the presence of an NO molecule bound to the heme iron with increasing partial occupancy. The occupancies for the different laser powers were 0.81 µJ = 0.39, 8.1 µJ = 0.50, 16.1 µJ = 0.65, 32.2 µJ = 0.58, 64.4 µJ = 0.84 and are summarized in Table S4. (f) Occupancy of NO for DtpB SSX structures collected with different laser energies, averaged across all six chains, as determined by three methods shown in blue (B-factor comparison), green (Fo − Fc map peak height) and red (multicopy refinement). Error bars show one standard deviation in the mean. Occupancy values in the deposited structures are taken from the occupancy refinement. Scaling and refinement statistics can be found in Table S2.

IUCrJ
Volume 12| Part 5| September 2025| Pages 582-594
ISSN: 2052-2525
https://doi.org/10.1107/S2052252525006645