Reference "The primary structure of a 4.0-kDa photosystem I polypeptide encoded by the chloroplast psaI gene"

Reference ID

8730

Title

The primary structure of a 4.0-kDa photosystem I polypeptide encoded by the chloroplast psaI gene

Source

The Journal of biological chemistry, 1989, vol. 264, pp. 18402-18406

Authors (6)

Scheller-H-V	Okkels-J-S
Hoj-P-B	Svendsen-I
Roepstorff-P	Moller-B-L

Abstract

Partial amino acid sequences have been determined for a 4.0-kDa photosystem I
polypeptide from barley. A comparison with the sequence of the chloroplast
genome of Nicotiana tabacum and Marchantia polymorpha identified the polypeptide
as chloroplast-encoded. We designate the corresponding gene psaI and the
polypeptide PSI-I. The barley chloroplast psaI gene was sequenced. The gene
encodes a polypeptide of 36 amino acid residues with a deduced molecular mass of
4008 Da. The 4.0-kDa polypeptide is N-terminally blocked with a formyl-
methionine residue. Plasma desorption mass spectrometry established that the
polypeptide is not post-translationally processed except for possible conversion
of a methionine residue into methionine sulfone. The hydrophobic 4.0-kDa
polypeptide is predicted to have one membrane-spanning alpha-helix and is
homologous to transmembrane helix E of the D2 reaction center polypeptide of
photosystem II.