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 g...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.展开更多
文摘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.
