The structure of the gene for the large subunit of ribulose 1,5-bisphosphate carboxylase from spinach chloroplast DNA

Abstract

A cloned fragment of spinach chloroplast DNA carrying the gene for the large subunit of ribulose bisphosphate (RuBP) carboxylase has been analysed by electron microscopy of R-loops, by hybridization to Northern blots of chloroplast RNA, by S1 nuclease mapping and by DNA sequencing. The transcribed region of the gene is 1690 +/- 3 nucleotides long and co-linear with its mRNA. It comprises a 178-179 bp 5' untranslated sequence, a 1425 bp coding region and an 85-88 bp 3' untranslated region. The deduced sequence of the 475 amino acids of the spinach large subunit protein shows 10% divergence from that of the maize large subunit protein (1). The nucleotide sequence divergence between spinach and maize over the same coding region is 16% but in the transcribed flanking regions it is 35%. Features of the spinach chloroplast gene which resemble those of bacterial genes include a 5-base Shine-Dalgarno sequence complementary to a sequence near the 3' end of chloroplast and bacterial 16S rRNA, a promoter region partially homologous to a consensus sequence of bacterial promoters, and a transcription termination region capable of forming a typical stem and loop structure.