Chloroplast phosphoglycerate kinase from Euglena gracilis: endosymbiotic gene replacement going against the tide.
Two chloroplast phosphoglycerate kinase isoforms from the photosynthetic flagellate Euglena gracilis were purified to homogeneity, partially sequenced, and subsequently cDNAs encoding phosphoglycerate kinase isoenzymes from both the chloroplast and cytosol of E. gracilis were cloned and sequenced. Chloroplast phosphoglycerate kinase, a monomeric enzyme, was encoded as a polyprotein precursor of at least four mature subunits that were separated by conserved tetrapeptides. In a Neighbor-Net analysis of sequence similarity with homologues from numerous prokaryotes and eukaryotes, cytosolic phosphoglycerate kinase of E. gracilis showed the highest similarity to cytosolic and glycosomal homologues from the Kinetoplastida. The chloroplast isoenzyme of E. gracilis did not show a close relationship to sequences from other photosynthetic organisms but was most closely related to cytosolic homologues from animals and fungi.
Institute of Botany III, Heinrich-Heine-University Düsseldorf, Germany.
Ulrich
U
Nowitzki
Gabriel
G
Gelius-Dietrich
Maike
M
Schwieger
Katrin
K
Henze
William
W
Martin
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002736:Chloroplasts / Q000201:enzymology*; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005056:Euglena gracilis / Q000201:enzymology*; D056890:Eukaryota / Q000235:genetics; D007527:Isoenzymes; D008969:Molecular Sequence Data; D010735:Phosphoglycerate Kinase / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D014176:Protein Biosynthesis / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification; D020539:Sequence Analysis, Protein / Q000379:methods; D017386:Sequence Homology, Amino Acid; D013559:Symbiosis / Q000235:genetics*
D018076:DNA, Complementary; D007527:Isoenzymes; D011498:Protein Precursors; D011994:Recombinant Proteins; D010735:Phosphoglycerate Kinase