5JRV

Crystal structure of Fe(II) NO-bound H-NOX protein from C. subterraneus

Summary for 5JRV

• Entry DOI: 10.2210/pdb5jrv/pdb
• Related: 5JRU 5JRX
• Descriptor: Methyl-accepting chemotaxis protein, PROTOPORPHYRIN IX CONTAINING FE, NITRIC OXIDE, ... (5 entities in total)
• Functional Keywords: heme-based methyl-accepting chemotaxis protein gas binding signaling protein, signaling protein
• Biological source: Caldanaerobacter subterraneus subsp. tengcongensis (strain DSM 15242 / JCM 11007 / NBRC 100824 / MB4)
• Total number of polymer chains: 2
• Total formula weight: 45514.89

Authors

Bruegger, J.,Hespen, C.,Phillips-Piro, C.M.,Marletta, M.A. (deposition date: 2016-05-06, release date: 2016-07-06, Last modification date: 2023-09-27)

Primary citation

Hespen, C.W.,Bruegger, J.J.,Phillips-Piro, C.M.,Marletta, M.A.
Structural and Functional Evidence Indicates Selective Oxygen Signaling in Caldanaerobacter subterraneus H-NOX.
Acs Chem.Biol., 11:2337-2346, 2016

PubMed Abstract: Acute and specific sensing of diatomic gas molecules is an essential facet of biological signaling. Heme nitric oxide/oxygen binding (H-NOX) proteins are a family of gas sensors found in diverse classes of bacteria and eukaryotes. The most commonly characterized bacterial H-NOX domains are from facultative anaerobes and are activated through a conformational change caused by formation of a 5-coordinate Fe(II)-NO complex. Members of this H-NOX subfamily do not bind O2 and therefore can selectively ligate NO even under aerobic conditions. In contrast, H-NOX domains encoded by obligate anaerobes do form stable 6-coordinate Fe(II)-O2 complexes by utilizing a conserved H-bonding network in the ligand-binding pocket. The biological function of O2-binding H-NOX domains has not been characterized. In this work, the crystal structures of an O2-binding H-NOX domain from the thermophilic obligate anaerobe Caldanaerobacter subterraneus (Cs H-NOX) in the Fe(II)-NO, Fe(II)-CO, and Fe(II)-unliganded states are reported. The Fe(II)-unliganded structure displays a conformational shift distinct from the NO-, CO-, and previously reported O2-coordinated structures. In orthogonal signaling assays using Cs H-NOX and the H-NOX signaling effector histidine kinase from Vibrio cholerae (Vc HnoK), Cs H-NOX regulates Vc HnoK in an O2-dependent manner and requires the H-bonding network to distinguish O2 from other ligands. The crystal structures of Fe(II) unliganded and NO- and CO-bound Cs H-NOX combined with functional assays herein provide the first evidence that H-NOX proteins from obligate anaerobes can serve as O2 sensors.

PubMed: 27328180
DOI: 10.1021/acschembio.6b00431

Experimental method

X-RAY DIFFRACTION (1.953 Å)