Intron-encoded open reading frame of the GIY-YIG subclass in a plastid gene.
Group-I introns, containing open reading frames (ORFs) that code for homing endonucleases, are widely distributed amongst eukaryotic organellar genomes. However, endonucleases of the GIY-YIG subclass have a restricted distribution in mitochondria and bacteriophages, and have never been observed in plastids. We have found the GIY-YIG motif in an intronic ORF within the previously published psbA gene sequence from Chlamydomonas reinhardtii chloroplasts. Based on phylogenetic analysis and an evaluation of amino-acid substitutions, this ORF is not closely related to any of the other GIY-YIG ORFs. These results suggest that GIY-YIG ORFs have a longer evolutionary history than previously assumed.
Département de Biochimie, Université de Montréal, Canada.
B
B
Paquin
C J
CJ
O'Kelly
B F
BF
Lang
D000595:Amino Acid Sequence; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000201:enzymology / Q000235:genetics; D004720:Endonucleases / Q000235:genetics*; D018014:Gene Transfer Techniques; D007438:Introns; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D045332:Photosystem II Protein Complex; D018087:Plastids; D017386:Sequence Homology, Amino Acid
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D004720:Endonucleases