XFEL Crystal Structures of Peroxidase Compound II

Hanna Kwon, Jaswir Basran, Chinar Pathak, Mahdi Hussain, Sam L Freeman, Alistair Fielding, Anna Bailey, Natalia Stefanou, Hazel A Sparkes, Takehiko Tosha, Keitaro Yamashita, Kunio Hirata, Hironori Murakami, Go Ueno, Hideo Ago, Kensuke Tono, Masaki Yamamoto, Hitomi Sawai, Yoshitsugu Shiro, Hiroshi SugimotoEmma Raven*, Peter Moody*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

14 Citations (Scopus)
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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 Fe-IV=O or Fe-IV-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 Fe-IV=O species. For Compound II, the nature of the ferryl heme is not unambiguously established. Here, we report 1.06 angstrom and 1.50 angstrom 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 (1.76 angstrom) is notably shorter than in APX (1.87 angstrom). 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.
Original languageEnglish
Pages (from-to)14578-14585
Number of pages8
JournalAngewandte Chemie - International Edition
Issue number26
Early online date19 Jun 2021
Publication statusPublished - 21 Jun 2021

Bibliographical note

Funding Information:
This work was supported by BBSRC grants BB/N015940/1 and BB/S020586/1 and travel grants from Diamond Light Source to P.C.E.M. and E.L.R. EPR experiments were carried out in the EPSRC National EPR Research Facility & Service (NS/A000055/1). We acknowledge access to SACLA (experiments (2018A8009, 2019B8009, 2020A8030) and JSPS for support (grant JP20H05452 to H.S. and JP19H05783 to M.Y.).

Publisher Copyright:
© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH


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