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Figure 6
The architecture of the catalytic site of the DA1472 variant and wild-type FucO is the same. The catalytic site of the DA1472 variant [PDB entry 7qnf, complexed with ethyl­eneglycol (EDO, cyan), Fe2+ and ADPR] is shown with yellow carbons and the superimposed active site of wild-type FucO [PDB entry 1rrm, complexed with ADPR and Zn2+, as well as S-(1,2)-propane­diol (PGO)] is shown with blue carbons. The Fe2+ ion of the DA1472 variant and the Zn2+ ion (not visible) of the wild-type superimpose exactly. The Fe2+ ion is coordinated by interactions with the side chains of Asp196, His200, His263 and His277 and with a water (Wat232) as well as an oxygen atom of the substrate ethyl­eneglycol. The latter interactions are highlighted by dotted lines. The oxygen atom of ethyl­eneglycol (EDO) of the 7qnf structure is replaced by an oxygen atom of (S)-1,2-propane­diol (PGO) in the 1rrm structure, whereas waters Wat232 and Wat138 correspond to waters bound in overlapping sites of the 1rrm structure. Wat138 is the catalytic water, which is hydrogen bonded to EDO, to the ribose moiety of ADPR and to NE2(His267) (dotted lines).

IUCrJ
Volume 10| Part 4| July 2023| Pages 437-447
ISSN: 2052-2525
https://doi.org/10.1107/S205225252300444X