https://www.selleckchem.com/TGF-beta.html DsbD also contributes reducing equivalents for the reduction of cytochrome c to facilitate heme attachment. The DsbD functional homolog CcdA is a 6 TM helix membrane protein that provides reducing equivalents for the reduction of cytochrome c. A recent structure determination of CcdA has provided critical insights into how reducing equivalents are transferred across the membrane that likely also provides understanding how this is achieved by DsbD as well. This structure and the insights gained are described. Auxin is a plant hormone that is central to plant growth and development from embryogenesis to senescence. Auxin signaling is mediated by auxin response transcription factors (ARFs) and Aux/IAA repressors that regulate the expression of a multitude of auxin response genes. ARF and Aux/IAA proteins assemble into homomeric and heteromeric complexes via their conserved PB1 domains. Here we report the first crystal structure of the PB1 complex between ARF5 and IAA17 of Arabidopsis thaliana, which represents the transcriptionally repressed state at low auxin levels. The PB1 domains assemble in a head-to-tail manner with a backbone arrangement similar to that of the ARF5ARF5 PB1 complex. The ARF5IAA17 complex, however, reveals distinct points of contact that promote the ARF5IAA17 interaction over the ARF5ARF5 interaction. Specifically, surface charges at the interface form salt bridges that distinguish the homomeric and heteromeric complexes, revealing common and specific interfaces between transcriptionally repressed and derepressed states. Further, the salt bridges can be reconfigured to switch the affinity between homomeric and heteromeric complexes in an incremental manner. The complex structure combined with quantitative binding analyses would be essential for deciphering the PB1 interaction code underlying the transcriptional regulation of auxin signaling. As the 2019 novel coronavirus disease (COVID-19) rapidly spread a