Fig. 6: Summary of the unique active site configurations observed in neutron structures of Mn3+SOD and Mn2+SOD.
From: Direct detection of coupled proton and electron transfers in human manganese superoxide dismutase
a Five-coordinate oxidized resting state. Of note, the data between the two Mn3+SOD chains suggest the proton bridging His30 and Tyr166 may be moving. Additionally, the His30 Nδ1 atom closest to WAT2 is observed to be both deprotonated and protonated. For brevity, the most plausible configuration is shown. b Five-coordinate reduced resting state. c Reduced six-coordinate state with –OH-bound opposite Asp159. Dashed lines represent normal hydrogen bonds, wide dashed lines are short-strong hydrogen bonds, and round-dotted lines are low-barrier hydrogen bonds. Portrayal of hydrogen bond lengths in 2D are not representative of those seen experimentally in 3D.
