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Publication Abstract from PubMed

Histamine dehydrogenase from the gram-negative bacterium Rhizobium sp. 4-9 (HaDHR) is a member of a small family of dehydrogenases containing a covalently attached FMN, and the only member so far identified to date that does not exhibit substrate inhibition. In this study, we present the 2.1 A resolution crystal structure of HaDHR. This new structure allowed for the identification of the internal electron transfer pathway to abiological ferrocene-based mediators. Alanine 437 was identified as the exit point of electrons from the Fe(4)S(4) cluster. The enzyme was modified with a Ser436Cys mutation to facilitate covalent attachment of a ferrocene moiety. When modified with Fc-maleimide, this new construct demonstrated direct electron transfer from the enzyme to a gold electrode in a histamine concentration-dependent manner without the need for any additional electron mediators.

Structure of Rhizobium sp. 4-9 histamine dehydrogenase and analysis of the electron transfer pathway to an abiological electron acceptor.,Goyal P, Deay D 3rd, Seibold S, Candido ACL, Lovell S, Battaile KP, Wilson GS, Richter ML, Petillo PA Arch Biochem Biophys. 2023 May 3;742:109612. doi: 10.1016/j.abb.2023.109612. PMID:37146865^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.