Structures of substrate- and product-bound forms of a multi-domain copper nitrite reductase shed light on the role of domain tethering in protein complexes

Sasaki, Daisuke, Watanabe, Tatiana F, Eady, Robert R, Garratt, Richard C, Antonyuk, Svetlana V ORCID: 0000-0002-2779-9946 and Hasnain, S Samar (2020) Structures of substrate- and product-bound forms of a multi-domain copper nitrite reductase shed light on the role of domain tethering in protein complexes. IUCrJ, 7 (3). pp. 557-565.

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Official URL: http://dx.doi.org/10.1107/s2052252520005230

Abstract

<jats:p>Copper-containing nitrite reductases (CuNiRs) are found in all three kingdoms of life and play a major role in the denitrification branch of the global nitrogen cycle where nitrate is used in place of dioxygen as an electron acceptor in respiratory energy metabolism. Several C- and N-terminal redox domain tethered CuNiRs have been identified and structurally characterized during the last decade. Our understanding of the role of tethered domains in these new classes of three-domain CuNiRs, where an extra cytochrome or cupredoxin domain is tethered to the catalytic two-domain CuNiRs, has remained limited. This is further compounded by a complete lack of substrate-bound structures for these tethered CuNiRs. There is still no substrate-bound structure for any of the as-isolated wild-type tethered enzymes. Here, structures of nitrite and product-bound states from a nitrite-soaked crystal of the N-terminal cupredoxin-tethered enzyme from the <jats:italic>Hyphomicrobium denitrificans</jats:italic> strain 1NES1 (<jats:italic>Hd</jats:italic> <jats:sub>1NES1</jats:sub>NiR) are provided. These, together with the as-isolated structure of the same species, provide clear evidence for the role of the N-terminal peptide bearing the conserved His27 in water-mediated anchoring of the substrate at the catalytic T2Cu site. Our data indicate a more complex role of tethering than the intuitive advantage for a partner-protein electron-transfer complex by narrowing the conformational search in such a combined system.</jats:p>

Item Type:	Article
Uncontrolled Keywords:	nitrogen cycle, denitrification, copper-containing nitrite reductase, electron transfer, catalysis, structural biology
Depositing User:	Symplectic Admin
Date Deposited:	07 May 2020 10:09
Last Modified:	18 Jan 2023 23:52
DOI:	10.1107/s2052252520005230
Open Access URL:	https://doi.org/10.1107/S2052252520005230
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3086349