5XS6:
reference: The Mesomeric Effect of Thiazolium on non-Kekule Diradicals in Pichia stipitis Transketolase., Hsu NS, Wang YL, Lin KH, Chang CF, Lyu SY, Hsu LJ, Liu YC, Chang CY, Wu CJ, Li TL, Angew Chem Int Ed Engl. 2018 Feb 12;57(7):1802-1807. doi: 10.1002/anie.201709799., Epub 2018 Jan 15. PMID: 29243887

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