Isolation and characterization of cDNA clones encoding photosystem I subunits with molecular masses 11.0, 10.0 and 8.4 kDa from Chlamydomonas reinhardtii.
cDNA clones encoding three photosystem I subunits of Chlamydomonas reinhardtii with apparent molecular masses 13, 5 and 3 kDa (thylakoid polypeptides 28, 35 and 37; P28, P35 and P37, respectively) were isolated using gene specific oligonucleotides as probes. The sequences of these oligonucleotides were deduced from the N-terminal amino acid sequences of the proteins. The cDNAs were sequenced and used to probe Southern and Northern blots. The Southern blot analysis indicates that the proteins are encoded by single-copy genes. The mRNA sizes of the three components are 960 (P28), 1120 (P35) and 790 (P37) nucleotides. Comparison between the open reading frames of the cDNAs and the N-terminal amino acid sequences of the proteins indicates that the nascent polypeptides possess N-terminal transit sequences that are removed to give mature proteins of 11.0 (P28), 10.0 (P35) and 8.4 (P37) kDa. Analysis of the deduced protein sequences suggests that P28 and P35 are extrinsic membrane proteins and that P37 spans the thylakoid membrane. All three proteins have short transit peptides that probably route them to the stromal side of the thylakoid membrane.
Franzén
L G
LG
Department of Molecular Biology, University of Geneva, Switzerland.
Frank
G
G
Zuber
H
H
Rochaix
J D
JD
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002696:Chlamydomonas / Q000235:genetics*; D002734:Chlorophyll / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015870:Gene Expression; D045342:Light-Harvesting Protein Complexes; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D045342:Light-Harvesting Protein Complexes; D008565:Membrane Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll; D004247:DNA