Characterization, cloning, and evolutionary history of the chloroplast and cytosolic class I aldolases of the red alga Galdieria sulphuraria.
Two fructose-1,6-bisphosphate aldolases from the acido- and thermophilic red alga Galdieria sulphuraria were purified to apparent homogeneity and N-terminally microsequenced. Both aldolases had similar biochemical properties such as Km (FBP) (5.6-5.8 microM) and molecular masses of the native enzymes (165kDa) as determined by size exclusion chromatography. The subunit size of the purified aldolases, as determined by SDS-PAGE, was 42kDa for both aldolases. The isoenzymes were not inhibited by EDTA or affected by cysteine or potassium ions, implying that they belong to the class I group of aldolases, while other red algae are known to have one class I and one class II aldolase inhibited by EDTA. cDNA clones of the cytosolic and plastidic aldolases were isolated and sequenced. The gene for the cytosolic isoenzyme contained a 303bp untranslated leader sequence, while the gene for the plastidic isoenzyme exhibited a transit sequence of 56 amino-acid residues. Both isoenzymes showed about 48% homology in the deduced amino-acid sequences. A gene tree relates both aldolases to the basis of early eukaryotic class I aldolases. The phylogenetic relationship to other aldolases, particularly to cyanobacterial class II aldolases, is discussed.
Gross
W
W
Institut für Pflanzenphysiologie und Mikrobiologie, Freie Universität Berlin, Königin-Luise-Str. 12-16a, 12169, Berlin, Germany.
Lenze
D
D
Nowitzki
U
U
Weiske
J
J
Schnarrenberger
C
C
D020418:Algal Proteins / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D002736:Chloroplasts / Q000201:enzymology*; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology; D019143:Evolution, Molecular; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D000461:Rhodophyta / Q000201:enzymology* / Q000235:genetics; D017385:Sequence Homology
D020418:Algal Proteins; D005634:Fructose-Bisphosphate Aldolase