Mapping the interface of alpha globin and eNOS: implications for increasing endogenous NO therapeutically

Abstract

Nitric oxide signaling is a powerful mechanism for the regulation of blood pressure homeostasis, inducing vasodilation and reducing peripheral resistance. As such, disruption of NO‐inhibitory protein interactions may prove to be a novel therapeutic for the treatment of hypertensive disease states. Focusing on the recent discovery of the alpha globin/eNOS complex in vascular endothelium, we have designed an alpha globin mimetic peptide that binds to eNOS and increases NO signaling and dilation. A key step in the development of therapeutic agents targeting this complex is a high‐resolution structural model of the binding interface of alpha globin and eNOS. Thus, we have used solution NMR to determine the relevant structural details of the alpha globin mimetic peptide known to bind to eNOS. Interestingly, this twenty residue peptide has a stable population of both proline cis and trans isomers, potentially influencing the affinity of the peptide/eNOS interaction. Crosslinking mass spectrometry allows for the mapping of interacting residues between the peptide and eNOS after enzymatic digestion. Using cis and trans proline peptide ensembles, we have generated models of the peptide/eNOS complex through docking simulations which can be verified with full‐length alpha globin. The different conformations adopted by the peptide allows for potential new interaction modes that may not be possible with full alpha globin protein, thereby possibly increasing peptide/protein binding affinity. Determining the binding interface of the alpha globin/eNOS complex allows for targeted searches for molecular inhibitors of this alpha globin/eNOS interaction, in efforts for novel therapeutics to combat vasoconstrictive disease.Support or Funding InformationAmerican Heart Association Grant 16PRE31180040 (TCSK)NIH 088554 (BEI)NIH 087828 (LC)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.