Structural and Functional Studies of the Mitochondrial Cysteine Desulfurase from Arabidopsis thaliana  

作　　者：Valeria R. Turowski Maria V. Busi Diego F. Gomez-Casati 

机构地区：[1]Centro de Estudios Fotosinteticos y Bioquimicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina and UniversidadNacional de General San Martin (UNSAM), Av. Gral Paz 5445, San Martin, Buenos Aires, Argentina

出　　处：《Molecular Plant》2012年第5期1001-1010,共10页分子植物（英文版）

摘　　要：AtNfsl is the Arabidopsis thaliana mitochondrial homolog of the bacterial cysteine desulfurases NifS and IscS, having an essential role in cellular Fe-S cluster assembly. Homology modeling of AtNfslm predicts a high global similarity with E. coil IscS showing a full conservation of residues involved in the catalytic site, whereas the chloroplastic AtNfs2 is more similar to the Synechocystis sp. SufS. Pull-down assays showed that the recombinant mature form, AtNfslm, specifically binds to Arabidopsis frataxin （AtFH）. A hysteretic behavior, with a lag phase of several minutes, was observed and hysteretic parameters were affected by pre-incubation with AtFH. Moreover, AtFH modulates AtNfslm kinetics, increasing Vmax and decreasing the S0.5 value for cysteine. Results suggest that AtFH plays an important role in the early steps of Fe-S cluster formation by regulating AtNfsl activity in plant mitochondria.AtNfsl is the Arabidopsis thaliana mitochondrial homolog of the bacterial cysteine desulfurases NifS and IscS, having an essential role in cellular Fe-S cluster assembly. Homology modeling of AtNfslm predicts a high global similarity with E. coil IscS showing a full conservation of residues involved in the catalytic site, whereas the chloroplastic AtNfs2 is more similar to the Synechocystis sp. SufS. Pull-down assays showed that the recombinant mature form, AtNfslm, specifically binds to Arabidopsis frataxin （AtFH）. A hysteretic behavior, with a lag phase of several minutes, was observed and hysteretic parameters were affected by pre-incubation with AtFH. Moreover, AtFH modulates AtNfslm kinetics, increasing Vmax and decreasing the S0.5 value for cysteine. Results suggest that AtFH plays an important role in the early steps of Fe-S cluster formation by regulating AtNfsl activity in plant mitochondria.

关 键 词：cysteine desulfurase Fe-S biogenesis MITOCHONDRIA ARABIDOPSIS frataxin. 

分 类 号：Q244[生物学—细胞生物学] X173[环境科学与工程—环境科学]