Identification of Key Intermediates during the NO and H 2 S Crosstalk Signaling Pathways.

The stable isomers and electronic states of [S,S,N,O]- species are investigated with a special focus on the most relevant isomers that could be involved in the NO/H2 S cross-talk pathways in biological media. This work identifies eight stable anions, among which are the already known cis-SSNO- and trans-SSNO- molecules and a new NO3 - -like anionic species, NS2 O- . Our computations show that the previously determined structure in lab experiment is trans-SSNO- , which is not relevant for biological activity in vivo. Instead, NS2 O- is proposed as the most likely key intermediate in vivo during important biological processes. This result alleviates the corresponding controversy in the literature.