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Figure 5
Composite view of the DBP showing four distinct BDE-100 binding sites depending on the mutation of Pgp. Transmembrane (TM) α-helices are shown as ribbons and are colored from the N-terminus to the C-terminus (blue to orange). Two critical TM helices known to bind multiple different ligands, TM6 and TM12, are labeled. Dual DBE-100 occupancy for the Y303A, Y306A and F728A mutants was apparent, in which the two binding sites are in opposing `halves' of the pseudosymmetric DBP. The F724A mutant structure was distinct from all others in that it contains a single BDE-100 bound in a novel site that lies on the axis of pseudosymmetry (dotted line), which we designate site 3. The rationale for the site nomenclature is as follows. Site 1 is the canonical site previously discovered by Nicklisch et al. (2016). Some structures with site 1 or site 1A occupancy also had a second site occupancy, which we designate site 2. Site 3 is the distinct novel single-site binding unique to F724A.

IUCrJ
Volume 7| Part 4| July 2020| Pages 663-672
ISSN: 2052-2525
https://doi.org/10.1107/S2052252520005709