biostudies-literatureUnknown4(1)Petrova ONHeme-Nitric oxide and Oxygen binding protein domains (H-NOX) are found in signaling pathways of both prokaryotes and eukaryotes and share sequence homology with soluble guanylate cyclase, the mammalian NO receptor. In bacteria, H-NOX is associated with kinase or methyl accepting chemotaxis domains. In the O₂-sensor of the strict anaerobe Caldanaerobacter tengcongensis (Ct H-NOX) the heme appears highly distorted after O₂ binding, but the role of heme distortion in allosteric transitions was not yet evidenced. Here, we measure the dynamics of the heme distortion triggered by the dissociation of diatomics from Ct H-NOX using transient electronic absorption spectroscopy in the picosecond to millisecond time range. We obtained a spectroscopic signature of the heme flattenCommunications chemistry31https://www.ebi.ac.uk/biostudies/studies/S-EPMC9814294biostudies-literatureUltrafast dynamics of heme distortion in the O₂-sensor of a thermophilic anaerobe bacterium.PMC9814294Negrerie MLamarre ISelles JNioche PYoo BKPetrova ONfalseUltrafast dynamics of heme distortion in the O₂-sensor of a thermophilic anaerobe bacterium.Heme-Nitric oxide and Oxygen binding protein domains (H-NOX) are found in signaling pathways of both prokaryotes and eukaryotes and share sequence homology with soluble guanylate cyclase, the mammalian NO receptor. In bacteria, H-NOX is associated with kinase or methyl accepting chemotaxis domains. In the O₂-sensor of the strict anaerobe Caldanaerobacter tengcongensis (Ct H-NOX) the heme appears highly distorted after O₂ binding, but the role of heme distortion in allosteric transitions was not yet evidenced. Here, we measure the dynamics of the heme distortion triggered by the dissociation of diatomics from Ct H-NOX using transient electronic absorption spectroscopy in the picosecond to millisecond time range. We obtained a spectroscopic signature of the heme flatten2021-01-01T00:00:00Z2021 Mar2026-05-27T20:56:00.355Z2024-12-03T17:18:28.186ZS-EPMC98142943669756610.1038/s42004-021-00471-9