Structure of a 3.2 kb region of pea chloroplast DNA containing the gene for the 44 kD photosystem II polypeptide

Abstract

The gene for the 44 kD chlorophyll a-binding photosystem II polypeptide has been localized on the pea (Pisum sativum) chloroplast genome. The nucleotide sequence of the gene and its flanking regions has been analyzed. The gene codes for a polypeptide of 473 amino acid residues and is possibly cotranscribed with the gene for the D2 photosystem II polypeptide with which it has 50 bp in common. The amino acid sequences of the 44 kD polypeptides from pea, spinach and maize are approximately 95% homologous. Within the 1 kb fragment 3′ to the 44 kD gene a 93 bp tRNA-Ser (UGA) gene and an open reading frame of 62 codons (ORF 62) were identified. Both show high homology to corresponding genes 3′ to the 44 kD genes from spinach, maize and barley. The 44 kD gene and ORF 62 are encoded in the same strand, and have putative promoter sequences, ribosome binding sites and transcription termination signals.