A proposed reaction mechanism for rice NADPH thioredoxin reductase C, an enzyme with protein disulfide reductase activity

Abstract

NADPH thioredoxin reductase C (NTRC) is an interesting NTR with a thioredoxin (Trx) domain at the C-terminus, able to conjugate both activities for 2-Cys peroxiredoxin (Prx) reduction. NTRC is dimeric in the presence of NADPH and interacted with dimeric 2-Cys Prx through the Trx module by a mixed disulfide between Cys377 of NTRC and Cys61 of the 2-Cys Prx. NTRC variants of both NTR and Trx active sites were inactive, but 1:1 mixtures of both variants allowed partial recovery of activity suggesting inter-subunit transfer of electrons during catalysis. Based on these results we propose a model for the reaction mechanism of NTRC. Structured summary MINT- 7017333: 2cys Prx (uniprotkb: Q6ER94) and 2cys Prx (uniprotkb: Q6ER94) bind (MI: 0407) by molecular sieving (MI: 0071) MINT- 7017101, MINT- 7017183: NTRC (uniprotkb: Q70G58) and 2cys Prx (uniprotkb: Q6ER94) bind (MI: 0407) by enzymatic studies (MI: 0415)