抄録
The biosynthesis of iron-sulfur clusters is a highly regulated process involving several proteins. Among them, so-called scaffold proteins play pivotal roles in both the assembly and delivery of iron-sulfur clusters. Here, we report the characterizations of chloroplast-localized CnfU proteins from Arabidopsis whose cyanobacterial homologue was proposed to serve as a molecular scaffold. Deficient mutants of AtCnfU-V, one of three chloroplastic NifU-like protein homologues, exhibited a dwarf phenotype, impaired protein levels of both ferredoxin and photosystem I, and a decrease in the in vitro insertion activity of iron-sulfur cluster. We propose that AtCnfU has an important function as a molecular scaffold for iron-sulfur cluster biosynthesis and therefore is required for the biogenesis of ferredoxin and photosystem I. In addition to the results above, we would like to present the latest data of other possible protein factors involved in iron-sulfur cluster biosynthesis in chloroplasts.
