The histidine brace: nature's copper alternative to haem?

Paul H. Walton*, Gideon J. Davies, Daniel E. Diaz, João P. Franco-Cairo

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review


The copper histidine brace is a structural unit in metalloproteins (Proc Natl Acad Sci USA 2011, 108, 15079). It consists of a copper ion chelated by the NH2 and π-N atom of an N-terminal histidine, and the τ-N atom of a further histidine, in an overall T-shaped coordination geometry (Nat Catal 2018, 1, 571). Like haem-containing proteins, histidine-brace-containing proteins have peroxygenase and/or oxygenase activity, where the substrates are notable for resistance to oxidation, for example, lytic polysaccharide monooxygenases (LPMOs). Moreover, the histidine brace is an invariant unit around which different protein structures exert different activities. Given the similarities in the diversity of function of proteins that contain either the copper histidine brace or haem, the question arises as to whether the functions of histidine brace-containing proteins duplicate those containing haem groups.

Original languageEnglish
Pages (from-to)485-494
Number of pages10
JournalFEBS Letters
Issue number4
Early online date29 Jan 2023
Publication statusPublished - 27 Feb 2023

Bibliographical note

© 2023 The Authors.
Funding Information:
GJD and PHW thank the Biotechnology and Biological Sciences Research Council for support (BB/R007705/1, BB/V0040069/1).


  • copper
  • haem
  • histidine brace
  • LPMOs

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