Abstract
The chloroplast nucleoid is a complex of chloroplast DNA (cpDNA) and various proteins. Sulfite reductase (SiR) is one of the major proteins of chloroplast nucleoid, which regulates the transcriptional activity of chloroplast nucleoid through changes in compaction of cpDNA. In addition, SiR is known to be a ferredoxin-dependent enzyme catalyzing the reduction of sulfite to sulfide. We analyzed quantitative and qualitative differences in SiR of plastid nucleoid during the greening of pea.
Nucleoids were isolated from pea etioplasts, and SiR was detected by immuno blot analysis. The content of SiR in etioplast nucleoids differed from that in chloroplast nucleoid. Two-dimensional electrophoresis and immuno blot analysis showed that isoelectric point of SiR was different in chloroplast subfractions. Currently, we are investigating the modification of SiR protein.
