title: Molecular evolution of phosphoenolpyruvate carboxylase for C4 photosynthesis in maize: comparison of its cDNA sequence with a newly isolated cDNA encoding an isozyme involved in the anaplerotic function.
abstract: Molecular events associated with the evolution of an enzyme for C4 photosynthesis were investigated. In maize, at least three isozymes of phosphoenolpyruvate carboxylase [EC 4.1.1.31] are known: the C4-form, the C2-form and the root-form, being named according to their physiological roles and pattern of tissue distribution [Ting, I.P. & Osmond, C.B. (1973) Plant Physiol. 51, 448-453]. A cDNA clone which presumably encodes the C3-form isozyme was newly isolated and analyzed. Comparison of the sequences of the C3-form and C4-form isozymes revealed that (i) the homologies in the nucleotide and deduced amino acid sequences were 71 and 77%, respectively, and (ii) the gene for the C4-form isozyme evolved under strong G/C pressure. The genes for these isozymes were found to be located apart on different chromosomes. A phylogenetic tree was constructed using 8 amino acid sequences of phosphoenolpyruvate carboxylases from various sources. The topology of the tree indicated that, at least in monocots such as maize and sorghum, the genes for the C4-form and C3-form isozymes diverged from their common ancestral gene earlier than the monocot-dicot divergence (about 2 x 10(8) yr ago), though the divergence of maize (C4 plant) from wheat (C3 plant) is supposed to have occurred much later (6 x 10(7) yr ago).
authors.affiliation: Department of Chemistry, Faculty of Science, Kyoto University.
authors.forename: T
authors.initials: T
authors.lastname: Kawamura
authors.forename: K
authors.initials: K
authors.lastname: Shigesada
authors.forename: H
authors.initials: H
authors.lastname: Toh
authors.forename: S
authors.initials: S
authors.lastname: Okumura
authors.forename: S
authors.initials: S
authors.lastname: Yanagisawa
authors.forename: K
authors.initials: K
authors.lastname: Izui
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification*; D017343:Genes, Plant; D006801:Humans; D007527:Isoenzymes / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D010788:Photosynthesis / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D003313:Zea mays / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D010940:Plant Proteins; D004247:DNA; D010730:Phosphoenolpyruvate Carboxylase