In:
Angewandte Chemie, Wiley, Vol. 132, No. 48 ( 2020-11-23), p. 21840-21846
Abstract:
Obtaining structures of intact redox states of metal centers derived from zero dose X‐ray crystallography can advance our mechanistic understanding of metalloenzymes. In dye‐decolorising heme peroxidases (DyPs), controversy exists regarding the mechanistic role of the distal heme residues aspartate and arginine in the heterolysis of peroxide to form the catalytic intermediate compound I (Fe IV =O and a porphyrin cation radical). Using serial femtosecond X‐ray crystallography (SFX), we have determined the pristine structures of the Fe III and Fe IV =O redox states of a B‐type DyP. These structures reveal a water‐free distal heme site that, together with the presence of an asparagine, imply the use of the distal arginine as a catalytic base. A combination of mutagenesis and kinetic studies corroborate such a role. Our SFX approach thus provides unique insight into how the distal heme site of DyPs can be tuned to select aspartate or arginine for the rate enhancement of peroxide heterolysis.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v132.48
DOI:
10.1002/ange.202008622
Language:
English
Publisher:
Wiley
Publication Date:
2020
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