Structural highlights
Function
TKT_PICST Catalyzes the transfer of a two-carbon ketol group from a ketose donor to an aldose acceptor, via a covalent intermediate with the cofactor thiamine pyrophosphate.
Publication Abstract from PubMed
Transketolase (TK) catalyzes a reversible transfer of a two-carbon (C2 ) unit between phosphoketose donors and phosphoaldose acceptors, for which the group-transfer reaction that follows a one- or two-electron mechanism and the force that breaks the C2"-C3" bond of the ketose donors remain unresolved. Herein, we report ultrahigh-resolution crystal structures of a TK (TKps) from Pichia stipitis in previously undiscovered intermediate states and support a diradical mechanism for a reversible group-transfer reaction. In conjunction with MS, NMR spectroscopy, EPR and computational analyses, it is concluded that the enzyme-catalyzed non-Kekule diradical cofactor brings about the C2"-C3" bond cleavage/formation for the C2 -unit transfer reaction, for which suppression of activation energy and activation and destabilization of enzymatic intermediates are facilitated.
Evidence of Diradicals Involved in the Yeast Transketolase Catalyzed Keto-Transferring Reactions.,Hsu NS, Wang YL, Lin KH, Chang CF, Ke SC, Lyu SY, Hsu LJ, Li YS, Chen SC, Wang KC, Li TL Chembiochem. 2018 Nov 16;19(22):2395-2402. doi: 10.1002/cbic.201800378. Epub 2018, Oct 18. PMID:30155962[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hsu NS, Wang YL, Lin KH, Chang CF, Ke SC, Lyu SY, Hsu LJ, Li YS, Chen SC, Wang KC, Li TL. Evidence of Diradicals Involved in the Yeast Transketolase Catalyzed Keto-Transferring Reactions. Chembiochem. 2018 Nov 16;19(22):2395-2402. doi: 10.1002/cbic.201800378. Epub 2018, Oct 18. PMID:30155962 doi:http://dx.doi.org/10.1002/cbic.201800378
