XFEL Crystal Structures of Peroxidase Compound II.
Angew Chem Weinheim Bergstr Ger
; 133(26): 14699-14706, 2021 Jun 21.
Article
em En
| MEDLINE
| ID: mdl-38505375
ABSTRACT
Oxygen activation in all heme enzymes requires the formation of high oxidation states of iron, usually referred to as ferryl heme. There are two known intermediates Compound I and Compound II. The nature of the ferryl heme-and whether it is an FeIV=O or FeIV-OH species-is important for controlling reactivity across groups of heme enzymes. The most recent evidence for Compound I indicates that the ferryl heme is an unprotonated FeIV=O species. For Compound II, the nature of the ferryl heme is not unambiguously established. Here, we report 1.06â
Å and 1.50â
Å crystal structures for Compound II intermediates in cytochrome c peroxidase (CcP) and ascorbate peroxidase (APX), collected using the X-ray free electron laser at SACLA. The structures reveal differences between the two peroxidases. The iron-oxygen bond length in CcP (1.76â
Å) is notably shorter than in APX (1.87â
Å). The results indicate that the ferryl species is finely tuned across Compound I and Compound II species in closely related peroxidase enzymes. We propose that this fine-tuning is linked to the functional need for proton delivery to the heme.
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MEDLINE
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En
Ano de publicação:
2021
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Article