The 23 KDa polypeptide of the photosynthetic oxygen-evolving complex from mustard seedlings (Sinapis alba L.). Nucleotide sequence of cDNA and evidence for phytochrome control of its mRNA abundance.

The nucleotide sequence of a cDNA from mustard shows 78% homology in deduced amino acid sequence for the mature protein compared to the sequence for the 23 kDa protein of the oxygen-evolving complex from spinach [(1987) FEBS Lett. 216, 234-240]. There is also a high degree of homology between the premature protein sequences concerning the hydrophobic domain and its distance from the suggested processing site. The accumulation of mRNA for the 23 kDa protein in mustard was stimulated by continuous far-red light and reversal experiments by means of red/far-red light pulse treatment show the involvement of phytochrome in controlling the mRNA abundance for the 23 kDa polypeptide in mustard. The accumulation of the mRNA can be inhibited in white light if the seedlings are treated with the herbicide Norflurazon.