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Cloning of a gene from Bacillus cereus with homology to the mreB gene from Escherichia coli. 总被引:2,自引:0,他引:2
We have cloned and sequenced a gene coding for a putative shape-determining protein (MreB) highly homologous to the mreB gene product of Escherichia coli. The amino acid (aa) identity was 53% and the similarity 72%. The gene is expressed early in the logarithmic phase. The aa sequence comparison showed that the protein, like the E. coli MreB, has structural similarity to actin and heat-shock protein Hsc70 encoded by a new super-gene family. 相似文献
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Molecular homology among members of the R gene family in maize. 总被引:2,自引:0,他引:2
Consonni G Geuna F Gavazzi G Tonelli C 《The Plant journal : for cell and molecular biology》1993,3(2):191-201
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Pavan Umate 《Plant signaling & behavior》2011,6(3):335-338
The enzymes called lipoxygenases (LOXs) can dioxygenate unsaturated fatty acids, which leads to lipoperoxidation of biological membranes. This process causes synthesis of signaling molecules and also leads to changes in cellular metabolism. LOXs are known to be involved in apoptotic (programmed cell death) pathway, and biotic and abiotic stress responses in plants. Here, the members of LOX gene family in Arabidopsis and rice are identified. The Arabidopsis and rice genomes encode 6 and 14 LOX proteins, respectively, and interestingly, with more LOX genes in rice. The rice LOXs are validated based on protein alignment studies. This is the first report wherein LOXs are identified in rice which may allow better understanding the initiation, progression and effects of apoptosis, and responses to bitoic and abiotic stresses and signaling cascades in plants.Key words: apoptosis, biotic and abiotic stresses, genomics, jasmonic acid, lipidsLipoxygenases (linoleate:oxygen oxidoreductase, EC 1.13.11.-; LOXs) catalyze the conversion of polyunsaturated fatty acids (lipids) into conjugated hydroperoxides. This process is called hydroperoxidation of lipids. LOXs are monomeric, non-heme and non-sulfur, but iron-containing dioxygenases widely expressed in fungi, animal and plant cells, and are known to be absent in prokaryotes. However, a recent finding suggests the existence of LOX-related genomic sequences in bacteria but not in archaea.1 The inflammatory conditions in mammals like bronchial asthama, psoriasis and arthritis are a result of LOXs reactions.2 Further, several clinical conditions like HIV-1 infection,3 disease of kidneys due to the activation of 5-lipoxygenase,4,5 aging of the brain due to neuronal 5-lipoxygenase6 and atherosclerosis7 are mediated by LOXs. In plants, LOXs are involved in response to biotic and abiotic stresses.8 They are involved in germination9 and also in traumatin and jasmonic acid biochemical pathways.10,11 Studies on LOX in rice are conducted to develop novel strategies against insect pests12 in response to wounding and insect attack,13 and on rice bran extracts as functional foods and dietary supplements for control of inflammation and joint health.14 In Arabidopsis, LOXs are studied in response to natural and stress-induced senescence,15 transition to flowering,16 regulation of lateral root development and defense response.17The arachidonic, linoleic and linolenic acids can act as substrates for different LOX isozymes. A hydroperoxy group is added at carbons 5, 12 or 15, when arachidonic acid is the substrate, and so the LOXs are designated as 5-, 12- or 15-lipoxygenases. Sequences are available in the database for plant lipoxygenases (EC:1.13.11.12), mammalian arachidonate 5-lipoxygenase (EC:1.13.11.34), mammalian arachidonate 12-lipoxygenase (EC:1.13.11.31) and mammalian erythroid cell-specific 15-lipoxygenase (EC:1.13.11.33). The prototype member for LOX family, LOX-1 of Glycine max L. (soybean) is a 15-lipoxygenase. The LOX isoforms of soybean (LOX-1, LOX-2, LOX-3a and LOX-3b) are the most characterized of plant LOXs.18 In addition, five vegetative LOXs (VLX-A, -B, -C, -D, -E) are detected in soybean leaves.19 The 3-dimensional structure of soybean LOX-1 has been determined.20,21 LOX-1 was shown to be made of two domains, the N-terminal domain-I which forms a β-barrel of 146 residues, and a C-terminal domain-II of bundle of helices of 693 residues21 (Fig. 1). The iron atom was shown to be at the centre of domain-II bound by four coordinating ligands, of which three are histidine residues.22Open in a separate windowFigure 1Three-dimensional structure of soybean lipoxygenase L-1. The domain I (N-terminal) and domain II (C-terminal) are indicated. The catalytic iron atom is embedded in domain II (PDB ID-1YGE).21This article describes identification of LOX genes in Arabidopsis and rice. The Arabidopsis genome encodes for six LOX proteins23 (www.arabidopsis.org) (Locus Annotation Nomenclature A* B* C* AT1G55020 lipoxygenase 1 (LOX1) LOX1 859 98044.4 5.2049 AT1G17420 lipoxygenase 3 (LOX3) LOX3 919 103725.1 8.0117 AT1G67560 lipoxygenase family protein LOX4 917 104514.6 8.0035 AT1G72520 lipoxygenase, putative LOX6 926 104813.1 7.5213 AT3G22400 lipoxygenase 5 (LOX5) LOX5 886 101058.8 6.6033 AT3G45140 lipoxygenase 2 (LOX2) LOX2 896 102044.7 5.3177