biostudies-literatureFukui KJapan Society for the Promotion of Science855-868https://www.ebi.ac.uk/biostudies/studies/S-EPMC9199185biostudies-literatureUnknown63(6)Phosphoribulokinase (PRK), one of the enzymes in the Calvin-Benson cycle, is a well-known target of thioredoxin (Trx), which regulates various enzyme activities by the reduction of disulfide bonds in a light-dependent manner. PRK has two Cys pairs conserved in the N-terminal and C-terminal regions, and the N-terminal one near the active site is thought to be responsible for the regulation. The flexible clamp loop located between the N-terminal two Cys residues has been deemed significant to Trx-mediated regulation. However, cyanobacterial PRK is also subject to Trx-dependent activation despite the lack of this clamp loop. We, therefore, compared Trx-mediated regulation of PRK from the cyanobacterium Anabaena sp. PCC 7120 (A.7120_PRK) and that from the land plant Arabidopsis thaliana (AtPRKPlant & cell physiologyThe Importance of the C-Terminal Cys Pair of Phosphoribulokinase in Phototrophs in Thioredoxin-Dependent Regulation.PMC9199185KAKENHI Grant Number [16H06556] and [21H02502]Yokochi YSekiguchi TWakabayashi KIMihara SFukui KYoshida KHisabori TfalseThe Importance of the C-Terminal Cys Pair of Phosphoribulokinase in Phototrophs in Thioredoxin-Dependent Regulation.Phosphoribulokinase (PRK), one of the enzymes in the Calvin-Benson cycle, is a well-known target of thioredoxin (Trx), which regulates various enzyme activities by the reduction of disulfide bonds in a light-dependent manner. PRK has two Cys pairs conserved in the N-terminal and C-terminal regions, and the N-terminal one near the active site is thought to be responsible for the regulation. The flexible clamp loop located between the N-terminal two Cys residues has been deemed significant to Trx-mediated regulation. However, cyanobacterial PRK is also subject to Trx-dependent activation despite the lack of this clamp loop. We, therefore, compared Trx-mediated regulation of PRK from the cyanobacterium Anabaena sp. PCC 7120 (A.7120_PRK) and that from the land plant Arabidopsis thaliana (AtPRK2022-01-01T00:00:00Z2022 Jun2026-04-08T10:32:04.02Z2025-02-19T02:57:26.314ZS-EPMC91991853541312010.1093/pcp/pcac050