Development of in-line anoxic small-angle X-ray scattering and structural characterization of an oxygen-sensing transcriptional regulator

Correlating Conformational Equilibria with Catalysis in the Electron Bifurcating EtfABCX of Thermotoga maritima

“…Here, we reveal the conformational malleability of EtfABCX and elucidate the structural transitions between its BF- and ET-associated states using a novel assay combining synchrotron SEC-MALS-SAXS, multiwavelength UV–visible spectroscopy, an anaerobic sample environment, and rigid body modeling using SAXS data and molecular dynamics to sample protein conformational space. 21 − 24 Our approach provides a platform for future anaerobic SEC-MALS-SAXS studies of BF systems, diverse oxidoreductase metalloenzymes, and other redox-sensitive systems reliant on domain motions. Applied here, this approach led to the identification of T. maritima EtfABCX solution states that are similar to static structures for homologous EtfAB-containing BF-enzymes and demonstrate bifurcation-like (B-like) and electron conducting-like (D-like) states.…”