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This content will become publicly available on February 5, 2019

Title: Artificial Metalloproteins Containing Co 4O 4Cubane Active Sites

Artificial metalloproteins (ArMs) containing Co 4O 4 cubane active sites were constructed via biotin-streptavidin technology. Stabilized by hydrogen bonds (H-bonds), terminal and cofacial Co III-OH 2 moieties are observed crystallographically in a series of immobilized cubane sites. Solution electrochemistry provided correlations of oxidation potential and pH. For variants containing Ser and Phe adjacent to the metallocofactor, 1e -/1H + chemistry predominates until pH 8, above which the oxidation becomes pH-independent. Installation of Tyr proximal to the Co 4O 4 active site provided a single H-bond to one of a set of cofacial Co III-OH 2 groups. With this variant, multi-e - /multi-H + chemistry is observed, along with a change in mechanism at pH 9.5 that is consistent with Tyr deprotonation. Finally, with structural similarities to both the oxygen-evolving complex of photosystem II (H-bonded Tyr) and to thin film water oxidation catalysts (Co 4O 4 core), these findings bridge synthetic and biological systems for water oxidation, highlighting the importance of secondary sphere interactions in mediating multi-e - /multi-H + reactivity.
Authors:
 [1] ;  [2] ; ORCiD logo [2] ;  [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [1]
  1. Univ. of California, Irvine, CA (United States). Dept. of Chemistry
  2. Univ. of California, Berkeley, CA (United States). Dept. of Physics
  3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Science Division
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 140; Journal Issue: 8; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Institutes of Health (NIH)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1433123