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1.
Nucleic Acids Res ; 28(2): 463-71, 2000 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-10606644

RESUMO

Most eubacteria, and all eukaryotes examined thus far, encode homologs of the DNA mismatch repair protein MutS. Although eubacteria encode only one or two MutS-like proteins, eukaryotes encode at least six distinct MutS homolog (MSH) proteins, corresponding to conserved (orthologous) gene families. This suggests evolution of individual gene family lines of descent by several duplication/specialization events. Using quantitative phylogenetic analyses (RASA, or relative apparent synapomorphy analysis), we demonstrate that comparison of complete MutS protein sequences, rather than highly conserved C-terminal domains only, maximizes information about evolutionary relationships. We identify a novel, highly conserved middle domain, as well as clearly delineate an N-terminal domain, previously implicated in mismatch recognition, that shows family-specific patterns of aromatic and charged amino acids. Our final analysis, in contrast to previous analyses of MutS-like sequences, yields a stable phylogenetic tree consistent with the known biochemical functions of MutS/MSH proteins, that now assigns all known eukaryotic MSH proteins to a monophyletic group, whose branches correspond to the respective specialized gene families. The rooted phylogenetic tree suggests their derivation from a mitochondrial MSH1-like protein, itself the descendent of the MutS of a symbiont in a primitive eukaryotic precursor.


Assuntos
Adenosina Trifosfatases , Proteínas de Bactérias/genética , Pareamento Incorreto de Bases , Reparo do DNA/genética , Proteínas de Ligação a DNA , Proteínas de Escherichia coli , Evolução Molecular , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/química , Duplicação Gênica , Humanos , Dados de Sequência Molecular , Proteína MutS de Ligação de DNA com Erro de Pareamento , Filogenia , Homologia de Sequência de Aminoácidos
2.
Gene ; 209(1-2): 167-74, 1998 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-9583948

RESUMO

Photosynthetic eukaryotes typically possess two distinct glyceraldehyde-3-phosphate dehydrogenases, an NAD+ -specific enzyme in the cytosol (GapC: EC 1.2.1.12) and an NADP+ -dependent enzyme in the chloroplast (GapAB: EC 1.2.1.13). The gymnosperm Pinus sylvestris is an exception in that it is known to express a gene encoding a transit peptide-bearing GapC-like subunit that is imported into chloroplasts (GapCp), but the enzymatic properties of this novel GAPDH have not been described from any source. We have expressed the mature GapCp unit from Pinus in Escherichia coli and have characterized the active enzyme. GapCp has a specific activity of 89 units per milligram and is strictly NAD+ -dependent, showing no detectable activity with NADP+. Values of the apparent Km for NAD+ and glyceraldehyde-3-phosphate were determined as 62 and 344 microM, respectively. The Pinus GapCpl gene possesses 12 introns, two in the region encoding the transit peptide and ten in the region encoding the mature subunit, all of which are found at positions strictly conserved across genes for higher plant GapC. A cDNA encoding a homologue of GapCp was isolated from the heterosporous fern Marsilea quadrifolia, indicating that NAD+ -dependent chloroplast GAPDH also occurs in other higher plants.


Assuntos
Cycadopsida/genética , Genes de Plantas , Gliceraldeído-3-Fosfato Desidrogenases/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Cloroplastos/enzimologia , Clonagem Molecular , Cycadopsida/enzimologia , Escherichia coli , Evolução Molecular , Gliceraldeído-3-Fosfato Desidrogenases/química , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Humanos , Íntrons , Cinética , Dados de Sequência Molecular , NAD/metabolismo , Filogenia , Pinus sylvestris , Mapeamento por Restrição , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
3.
J Mol Evol ; 39(1): 34-46, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8064871

RESUMO

Nuclear protein coding sequences from gymnosperms are currently scarce. We have determined 4 kb of nuclear protein coding sequences from gynosperms and have collected and analyzed > 60 kb of nuclear sequences from gymnosperms and nonspermatophytes in order to better understand processes influencing genome evolution in plants. We show that conifers possess both biased and nonbiased genes with respect to GC content, as found in monocots, suggesting that the common ancestor of conifers and monocots may have possessed both biased and nonbiased genes. The lack of biased genes in dicots is suggested to be a derived character for this lineage. We present a simple but speculative model of land-plant genome evolution which considers changes in GC bias and CpG frequency, respectively, as independent processes and which can account for several puzzling aspects of observed nucleotide frequencies in plant genes.


Assuntos
Evolução Biológica , Citosina , Genoma , Guanina , Plantas/genética , Composição de Bases , Sequência de Bases , Clonagem Molecular , Genes de Plantas , Dados de Sequência Molecular , Especificidade da Espécie , Árvores/genética
4.
Plant Mol Biol ; 26(4): 1155-66, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7811973

RESUMO

Angiosperms and algae possess two distinct glyceraldehyde-3-phosphate dehydrogenase (GAPDH) enzymes, an NAD(+)-dependent tetramer involved in cytosolic glycolysis and an NADP(+)-dependent enzyme of the Calvin cycle in chloroplasts. We have found that the gymnosperm Pinus sylvestris possesses, in addition to these, a nuclear-encoded, plastid-specific, NAD(+)-dependent GAPDH, designated GapCp, which has not previously been described from any plant. Several independent full-size cDNAs for this enzyme were isolated which encode a functional transit peptide and mature subunit very similar to that of cytosolic GAPDH of angiosperms and algae. A molecular phylogeny reveals that chloroplast GapCp and cytosolic GapC arose through gene duplication early in chlorophyte evolution. The GapCp gene is expressed as highly as that for GapC in light-grown pine seedlings. These findings suggest that aspects of compartmentalized sugar phosphate metabolism may differ in angiosperms and gymnosperms and furthermore underscore the contributions of endosymbiotic gene transfer and gene duplication to the nuclear complement of genes for enzymes of plant primary metabolism.


Assuntos
Compartimento Celular , Núcleo Celular/genética , Gliceraldeído-3-Fosfato Desidrogenases/genética , Plastídeos/enzimologia , Sequência de Aminoácidos , Sequência de Bases , Evolução Biológica , Transporte Biológico , Sistema Livre de Células , Cloroplastos/metabolismo , Clonagem Molecular , Gliceraldeído-3-Fosfato Desidrogenases/biossíntese , Dados de Sequência Molecular , NAD/metabolismo , Pisum sativum/metabolismo , Pinus sylvestris , Biossíntese de Proteínas , Sinais Direcionadores de Proteínas/genética , Sinais Direcionadores de Proteínas/metabolismo , Homologia de Sequência de Aminoácidos , Especificidade por Substrato , Transcrição Gênica
5.
Proc Natl Acad Sci U S A ; 95(8): 4126-33, 1998 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-9539701

RESUMO

This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C10, C15, and C20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology and mechanism of terpenoid cyclization is followed by a discussion of molecular cloning and heterologous expression of terpenoid synthases. Sequence relatedness and phylogenetic reconstruction, based on 33 members of the Tps gene family, are delineated, and comparison of important structural features of these enzymes is provided. The review concludes with an overview of the organization and regulation of terpenoid metabolism, and of the biotechnological applications of terpenoid synthase genes.


Assuntos
Evolução Molecular , Liases Intramoleculares/química , Filogenia , Plantas/classificação , Plantas/enzimologia , Terpenos/metabolismo , Sequência de Aminoácidos , Sequência Conservada , Dados de Sequência Molecular , Plantas/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
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