RESEARCH ARTICLE Allosteric activation of the nitric oxide receptor soluble guanylate cyclase mapped by cryo-electron microscopy Benjamin G Horst1†, Adam L Yokom2,3†, Daniel J Rosenberg4,5, Kyle L Morris2,3‡, Michal Hammel4, James H Hurley2,3,4,5*, Michael A Marletta1,2,3* 1Department of Chemistry, University of California, Berkeley, Berkeley, United States; 2Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States; 3Graduate Group in Biophysics, University of California, Berkeley, Berkeley, United States; 4Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, United States; 5California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States Abstract Soluble guanylate cyclase (sGC) is the primary receptor for nitric oxide (NO) in mammalian nitric oxide signaling. We determined structures of full-length Manduca sexta sGC in both inactive and active states using cryo-electron microscopy. NO and the sGC-specific stimulator YC-1 induce a 71˚ rotation of the heme-binding b H-NOX and PAS domains. Repositioning of the b *For correspondence: H-NOX domain leads to a straightening of the coiled-coil domains, which, in turn, use the motion to
[email protected] (JHH); move the catalytic domains into an active conformation. YC-1 binds directly between the b H-NOX
[email protected] (MAM) domain and the two CC domains. The structural elongation of the particle observed in cryo-EM was †These authors contributed corroborated in solution using small angle X-ray scattering (SAXS). These structures delineate the equally to this work endpoints of the allosteric transition responsible for the major cyclic GMP-dependent physiological Present address: ‡MRC London effects of NO.