Structure of the chloroplast gene for the precursor of the M_r32,000 photosystem II protein from mustard (<i>Sinapis alba</i>L.)

Abstract

The nucleotide sequence of the mustard chloroplast gene for the precursor of the Mr 32,000 photosystem II protein is presented. A comparison with the corresponding genes from spinach and Nicotiana debneyi (14) reveals less than 5% nucleotide divergence in the coding region. The derived protein of mustard differs from the corresponding proteins by three amino acid positions at the C-terminus. We have defined the presumed transcription start and termination sites of the mustard gene. Upstream from the start site are sequences typical of a prokaryotic promoter and, also, a sequence that resembles the eukaryotic 'TATA' box. A search for intrastrand base pairing revealed stem-loop secondary structure at the transcription start and termination sites and in the region preceding the presumed promoter. This latter region is a 69-base-pair sequence element unique to the 5'flanking sequence of the mustard gene.