A Five‐Base‐Pair‐Deletion in the Gene for the Large Subunit Causes the Lesion in the Ribulose Bisphosphate Carboxylase/Oxygenase‐Deficient Plastome Mutant Sigma of <i>Oenothera hookeri</i>

Abstract

Abstract The gene for the large subunit of ribulose bisphosphate carboxylase/oxygenase (rbcL) has been mapped on the Oenothera hookeri plastid chromosome. It is located close to the gene for the herbicide‐binding “32 kd” protein of the photosystem II reaction center (psbA), at a position different from that found in the ancestral angiosperm type of plastid chromosomes, due to an inversion in the large single‐copy region. The gene codes for a polypeptide of 475 amino acid residues corresponding to a molecular mass of 52.7 kd. The deduced amino acid composition diverges by 4.8% from the amino acid sequence of the spinach protein and by 8.2% from that of maize. The corresponding nucleotide sequences differ by 8.5 % and 15 % from each other. The rbcL gene of the RuBPcase/oase‐deficient Oenothera plastome mutant sigma contains a TTAAC deletion at amino acid residues 270/271 which introduces a frame shift and an amber stop codon seven triplets later. This lesion which probably arose by slipped mispairing is consistent with the previously observed, virtually full‐length mRNA that is decoded into a truncated large subunit polypeptide of approximately 30 kd in vitro and in vivo .