Water influences on the copper active site in hemocyanin

Daniel Panzer, Christian Beck, Michaela Hahn, Jochen Maul, Gerd Schönhense, Heinz Decker, Emad F. Aziz

Research output: Contribution to journalArticleResearchpeer-review

14 Citations (Scopus)


Active metal sites play a key role in the biochemistry of oxygen transport by hemocyanins. Observing the changes in the local electronic structure of the copper sites upon oxygenation is thus essential for understanding their biological functionality. Here, direct access to the electronic structure of the active copper sites in hemocyanin is achieved via L-edge X-ray absorption spectroscopy under physiological conditions. We compare the deoxygenated and the oxygenated states of native hemocyanin and find evidence that the oxygenation does not simply switch the copper valence state between Cu I and Cu II, as assumed classically. In the deoxygenated state, water molecules can enter the active site and keep the copper atoms partially oxidized. The role of water in this process has never been revealed before for lack of L-edge spectroscopy on copper in solution. Besides providing a more detailed electronic picture for the oxygenation process, this study opens a new chapter in investigating the function of proteins under in-vivo-like conditions.

Original languageEnglish
Pages (from-to)1642-1647
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number10
Publication statusPublished - 20 May 2010
Externally publishedYes

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