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The single‐copy gene psbS codes for a phylogenetically intriguing 22 kDa polypeptide of photosystem II
Author(s) -
Wedell N.,
Klein R.,
Ljungberg U.,
Andersson B.,
Herrmann R.G.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81462-u
Subject(s) - transit peptide , gene , biology , biochemistry , transmembrane protein , photosystem ii , transmembrane domain , gene duplication , photosystem i , rna , peptide sequence , genetics , chloroplast , plastid , receptor , photosynthesis
Recombinant phages that encode the complete precursor polypeptide for the 22 kDa polypeptide associated with photosystem 11 have been serologically selected from two λgt11 expression libraries made from polyadenylated RNA or spinach seedlings. The cDNAs hybridize to a 1.3 kb RNA species. The precursor protein is comprised of 274 amino acid residues and carries an N‐terminal transit peptide of probably 69 amino acid residues. The mature protein exhibits four, predicted transmembrane segments and is shown to be an integral component of photosystom 11 originating in a single‐copy gene. The unique characteristics of this protein are: (1) it is the result of a gene‐internal duplication of an ancestor with two membrane spans. (ii) a striking resemblance to LHC 1/11, CP24/CP29 apoproteins, and ELIPs, although it does not bind chlorophyll and is present in cyanobacteria, and, as these proteins, (iii) it integrates into the membrane with uncleaved routing signals that display remarkable resemblance to patterns found in bipartite transit pepticies.