The primary structure of a cDNA for PsaN, encoding an extrinsic lumenal polypeptide of barley photosystem I.
A cDNA clone encoding a 15,501 Da photosystem I (PSI) subunit of barley was isolated using an oligonucleotide based on the NH2-terminal amino acid sequence of the isolated protein. The polypeptide, which migrates with an apparent molecular mass of 9.5 kDa on denaturing SDS-PAGE, has been designated PSI-N, and the corresponding gene is PsaN. Analysis of the deduced protein sequence indicates a mature protein of 85 amino acid residues and a molecular mass of 9818 Da. PSI-N is a hydrophilic, extrinsic protein with no predicted membrane-spanning regions. The transit peptide of 60 residues (5683 Da) contains a predicted hydrophobic alpha-helix, suggesting that the protein is routed into the thylakoid lumen. Thus, PSI-N is the second known lumenal protein component associated with PSI, together with PSI-F.
Department of Physiology, Carlsberg Laboratory, Copenhagen Valby, Denmark.
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Knoetzel
D J
DJ
Simpson
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001483:Base Sequence; D002451:Cell Compartmentation; D002736:Chloroplasts / Q000737:chemistry*; D003001:Cloning, Molecular; D001467:Hordeum / Q000235:genetics*; D007425:Intracellular Membranes / Q000737:chemistry; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000235:genetics; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D045331:Photosystem I Protein Complex; D021382:Protein Sorting Signals / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D021382:Protein Sorting Signals; D012333:RNA, Messenger; C081674:photosystem I, PSI-N subunit