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1.
2.
Identification of different protein functions facilitates a mechanistic understanding of Japanese encephalitis virus (JEV) infection and opens novel means for drug development. Support vector machines (SVM), useful
for predicting the functional class of distantly related proteins, is employed to ascribe a possible functional class to Japanese encephalitis virus protein. Our study from SVMProt and available JE virus sequences
suggests that structural and nonstructural proteins of JEV genome possibly belong to diverse protein functions, are expected to occur in the life cycle of JE virus. Protein functions common to both structural and
non-structural proteins are iron-binding, metal-binding, lipid-binding, copper-binding, transmembrane, outer membrane, channels/Pores - Pore-forming toxins (proteins and peptides) group of proteins. Non-structural
proteins perform functions like actin binding, zinc-binding, calcium-binding, hydrolases, Carbon-Oxygen Lyases, P-type ATPase, proteins belonging to major facilitator family (MFS), secreting main terminal branch (MTB)
family, phosphotransfer-driven group translocators and ATP-binding cassette (ABC) family group of proteins. Whereas structural proteins besides belonging to same structural group of proteins (capsid, structural, envelope),
they also perform functions like nuclear receptor, antibiotic resistance, RNA-binding, DNA-binding, magnesium-binding, isomerase (intra-molecular), oxidoreductase and participate in type II (general) secretory pathway (IISP). 相似文献
3.
Analysis of the distribution and structure of integrated Banana streak virus DNA in a range of Musa cultivars 总被引:2,自引:0,他引:2
Andrew D. W. Geering Neil E. Olszewski Ganesh Dahal John E. Thomas Benham E. L. Lockhart 《Molecular Plant Pathology》2001,2(4):207-213
Banana streak virus strain OL (BSV-OL) commonly infects new Musa hybrids, and this infection is thought to arise de novo from integrated virus sequences present in the nuclear genome of the plant. Integrated DNA (Musa6+8 sequence) containing the whole genome of the virus has previously been cloned from cv. Obino l’Ewai (Musa AAB group), a parent of many of the hybrids. Using a Southern blot hybridization assay, we have examined the distribution and structure of integrated BSV-OL sequences in a range of Musa cultivars. For cv. Obino l’Ewai, almost every restriction fragment hybridizing to BSV-OL was predicted from the Musa6+8 sequence, suggesting that this is the predominant type of BSV-OL integrant in the genome. Furthermore, since only two junction fragments of Musa/BSV sequence were detected, and the Musa6+8 sequence is believed to be integrated as multiple copies in a tandem array, then the internal Musa spacer sequences must be highly conserved. Similarly sized restriction fragments were detected in four BB group cultivars, but not in six AA or AAA group cultivars, suggesting that the BSV-OL sequences are linked to the B-genome of Musa. We also provide evidence that cv. Williams (Musa AAA group) contains a distinct badnavirus integrant that is closely related to the ‘dead’ virus integrant previously characterized from Calcutta 4 (Musa acuminata ssp. burmannicoides). Our results suggest that the virus integrant from cv. Williams is linked to the A-genome, and the complexity of the hybridization patterns suggest multiple sites of integration and/or variation in sequence and structure of the integrants. 相似文献
4.
Sudha Rao Gopalakrishna Kamath Gururaj Maralihalli Anil S. Bhagwat 《Photosynthesis research》1987,12(2):155-164
The -aminolevulinic acid dehydratase activity was irreversibly inactivated by irradiation of the enzyme in presence of flavin mononucleotide. The loss of enzyme activity was dependent on time of irradiation, concentration of FMN and intensity of irradiance. It required oxygen and was markedly enhanced in heavy water. The presence of levulinic acid (a competitive inhibitor of -ALAD) during irradiation prevented the inactivation considerably indicating photooxidative damage at or near the active site. Superoxide dismutase, sodium benzoate and sodium formate offered no protection, but singlet oxygen quenchers like azide and tryptophan were effective. NADH, electron donor to excited flavins, also prevented the loss of enzyme activity. These results indicate that singlet oxygen produced by light absorption of FMN was responsible for the photooxidative inhibition of the enzyme.Abbreviations ALAD
-aminolevulinic acid dehydratase
- FMN
flavin mononucleotide
- O2
-
superoxide
- H2O2
hydrogen peroxide
- 102
singlet oxygen
- LA
levulinic acid
- PBG
porphobilinogen
- BSA
bovine serum albumin
- BME
2-mercaptoethanol
- SOD
superoxide dismutase
- pHMB
para-hydroxymercuribenzoate
- DTT
dithiothreitol
- FAD
flavin adenine dinucleotide
- NADH
nicotinamide adenine dinucleotide 相似文献
5.
Oligonucleotides, part 5+: synthesis and fluorescence studies of DNA oligomers d(AT)5 containing adenines covalently linked at C-8 with dansyl fluorophore. 总被引:1,自引:1,他引:0
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The synthesis of oligodeoxynucleotides d(AT)5 in which specific adenines are linked at C-8 position with dansyl fluorophores via a variable polymethylene spacer chain are reported. This was achieved by a strategy involving prelabelling at the monomeric stage followed by solid phase assembly of oligonucleotides to obtain regiospecifically labeled oligonucleotides. Several mono and polydansyl d(AT)5 derivatives in which the fluorophore is linked via ethylene, tetramethylene and hexamethylene spacer arms were synthesised for a systematic study of their fluorescence characteristics. It was observed that (i) enhancements in fluorescence intensity and emission quantum yields are seen due to multiple labelling, (ii) the magnitude of enhancements are related to labelling configuration and (iii) quenching efficiency is minimal with shorter and rigid spacer arms. The results may aid rational design of multiple fluorescent DNA probes for nonradioactive detection of nucleic acids. 相似文献
6.
S. S. Bhagwat C. Boswell C. Gude N. Contardo D. S. Cohen J. Mathis R. Dotson W. Lee S. Shetty 《Bioorganic & medicinal chemistry letters》1992,2(12):1619-1622
(3-Pyridinyl)alkanoic acids substituted at the 4-position with an (arylsulfonamido)alkyl group were synthesized and found to behave as platelet thromboxane receptor antagonists (TxRAs) and thromboxane synthase inhibitors (TxSIs). The compounds behaved as agonists at the vascular receptor for thromboxane A2. 相似文献
7.
Beta-glucan synthesis in Bradyrhizobium japonicum: characterization of a new locus (ndvC) influencing beta-(1-->6) linkages.
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Bradyrhizobium japonicum synthesizes periplasmic cyclic beta-(1-->3),beta-(1-->6)-D-glucans during growth in hypoosmotic environments, and evidence is growing that these molecules may have a specific function during plant-microbe interactions in addition to osmoregulation. Site-directed Tn5 mutagenesis of the DNA region upstream of ndvB resulted in identification of a new gene (ndvC) involved in beta-(1--> 3), beta-(1-->6)-glucan synthesis and in nodule development. The predicted translation product was a polypeptide (ca. 62 kDa) with several transmembrane domains. It contained a sequence characteristic of a conserved nucleoside-sugar-binding motif found in many bacterial enzymes and had 51% similarity with a beta-glucanosyltransferase from Candida albicans. B. japonicum carrying a Tn5 insertion in ndvC resulted in synthesis of altered cyclic beta-glucans composed almost entirely of beta-(1--> 3)-glycosyl linkages. The mutant strain was only slightly sensitive to hypoosmotic growth conditions compared with the ndvB mutant, but it was severely impaired in symbiotic interactions with soybean (Glycine max). Nodulation was delayed by 8 to 10 days, and many small nodule-like structures apparently devoid of viable bacteria were formed. This finding suggests that the structure of the beta-glucan molecule is important for a successful symbiotic interaction, and beta-glucans may have a specific function in addition to their role in hypoosmotic adaptation. 相似文献
8.
Stimulation of in vitro shoot proliferation from nodal explants of cassava by thidiazuron, benzyladenine and gibberellic acid 总被引:2,自引:0,他引:2
Basdeo Bhagwat Luiz G. F. Vieiral Larry R. Erickson 《Plant Cell, Tissue and Organ Culture》1996,46(1):1-7
Multiple shoots were produced from nodal explants of cassava (Manihot esculenta Crantz) by a two-step procedure: a 6- to 8-day exposure to 0.11–0.22 µM thidiazuron (TDZ) in liquid Murashige and Skoog (MS) medium followed by culture on agar-solidified MS medium supplemented with 2.2 µM 6-benzyladenine (BA) and 1.6 M gibberellic acid (GA3). TDZ caused the nodal explants to expand and this expansion (growth) continued during culture with BA and GA3. From this expanded explant, clusters of buds and fasciated stems developed continuously and these gave rise to shoots. The shoot proliferation process was open-ended, yielding an average of 31.5 shoots per nodal explant after 10 weeks of culture with genotype CG 1–56. A positive response was also obtained from seven other genotypes evaluated with this protocol.Abbreviations BA
6-benzyladenine
- BM
basal medium
- DPU
1,3-diphenylurea
- GA3
gibberellie acid
- 2iP
isopentenyladenine
- MSM
multiple shoot medium
- NAA
1-naphthaleneacetic acid
- PGR
plant growth regulator
- TDZ
thidiazuron
- Z
zeatin 相似文献
9.
The production of antimicrobial phytoalexins is one of the best-known inducible defence responses following microbial infection of plants or treatment with elicitors. In the legume soybean (Glycine max L.), 1,3-1,6--glucans derived from the fungal pathogen Phytophthora sojae have been identified as potent elicitors of the synthesis of the phytoalexin, glyceollin. Recently it has been reported that during symbiotic interaction between soybean and the nitrogen-fixing bacterium Bradyrhizobium japonicum USDA 110 the bacteria synthesize cyclic 1,3-1,6--glucans. Here we demonstrate that both the fungal and the bacterial -glucans are ligands of -glucan-binding sites which are putative receptors for the elicitor signal compounds in soybean roots. Whereas the fungal -glucans stimulate phytoalexin synthesis at low concentrations, the bacterial cyclic 1,3-1,6--glucans appear to be inactive even at relatively high concentrations. Competition studies indicate that increasing concentrations of the bacterial 1,3-1,6--glucans progressively inhibit stimulation of phytoalexin synthesis in a bioassay induced by the fungal 1,3-1,6--glucans. Another type of cyclic -glucan, a 1,2--glucan from Rhizobium meliloti, that does not nodulate on soybean, seems to be inactive as elicitor and as ligand of the -glucan-binding sites. These results may indicate a novel mechanism for a successful plant-symbiont interaction by suppressing the plant's defence response.Abbreviations HG-APEA
1-[2-(4-aminophenyl)ethyl]amino-l-[hexaglucosyl]deoxyglucitol
- HG-AzPEA
l-[2-(4-azidophenyl)-ethyl]amino-l-[hexaglucosyl]deoxyglucitol
- IC50
concentration for half-maximal displacement
We thank Ines Arlt for excellent technical assistance. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 369), the Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie, Fonds der Chemischen Industrie (J.E.), and USDA CSRS NRI Competitive Research grant 93373059233 (A.A.B.). 相似文献
10.
The cysteine conserved among DNA cytosine methylases is required for methyl transfer, but not for specific DNA binding. 总被引:9,自引:5,他引:4
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M W Wyszynski S Gabbara E A Kubareva E A Romanova T S Oretskaya E S Gromova Z A Shabarova A S Bhagwat 《Nucleic acids research》1993,21(2):295-301
All DNA (cytosine-5)-methyltransferases contain a single conserved cysteine. It has been proposed that this cysteine initiates catalysis by attacking the C6 of cytosine and thereby activating the normally inert C5 position. We show here that substitutions of this cysteine in the E. coli methylase M. EcoRII with either serine or tryptophan results in a complete loss of ability to transfer methyl groups to DNA. Interestingly, mutants with either serine or glycine substitution bind tightly to substrate DNA. These mutants resemble the wild-type enzyme in that their binding to substrate is not eliminated by the presence of non-specific DNA in the reaction, it is sensitive to methylation status of the substrate and is stimulated by an analog of the methyl donor. Hence the conserved cysteine is not essential for the specific stable binding of the enzyme to its substrate. However, substitution of the cysteine with the bulkier tryptophan does reduce DNA binding. We also report here a novel procedure for the synthesis of DNA containing 5-fluorocytosine. Further, we show that a DNA substrate for M. EcoRII in which the target cytosine is replaced by 5-fluorocytosine is a mechanism-based inhibitor of the enzyme and that it forms an irreversible complex with the enzyme. As expected, this modified substrate does not form irreversible complexes with the mutants. 相似文献