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A charge polarization model for the metal-specific activity of superoxide dismutases

DOI: 10.1039/C7CP06829H DOI Help

Authors: Anna Barwinska-sendra (Newcastle University) , Arnaud Baslé (Newcastle University) , Kevin J. Waldron (Newcastle University) , Sun Un (Université Paris-Saclay)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Chemistry Chemical Physics , VOL 13

State: Published (Approved)
Published: December 2017
Diamond Proposal Number(s): 7864 , 9948

Abstract: The pathogenicity of Staphylococcus aureus is enhanced by having two superoxide dismutases (SODs): a Mn-specific SOD and another that can use either Mn or Fe. Using 94 GHz electron-nuclear double resonance (ENDOR) and electron double resonance detected (ELDOR)-NMR we show that, despite their different metal-specificities, their structural and electronic similarities extend down to their active-site 1H– and 14N–Mn(II) hyperfine interactions. However these interactions, and hence the positions of these nuclei, are different in the inactive Mn-reconstituted Escherichia coli Fe-specific SOD. Density functional theory modelling attributes this to a different angular position of the E. coli H171 ligand. This likely disrupts the Mn–H171–E170′ triad causing a shift in charge and in metal redox potential, leading to the loss of activity. This is supported by the correlated differences in the Mn(II) zero-field interactions of the three SOD types and suggests that the triad is important for determining metal specific activity.

Subject Areas: Chemistry, Biology and Bio-materials

Instruments: I04-Macromolecular Crystallography