Disease relevance of ECs4082

• A potential promoter with a sequence homologous to that of cAMP-CRP-activated promoters in E. coli was identified upstream of ORF3, the gene preceding mshA [1].
• The genomic RNA of beet western yellows virus (BWYV) contains a potential translational frameshift signal in the overlap region of open reading frames ORF2 and ORF3 [2].
• A deletion/insertion mutation lacking the 3' end of ORF1, all of galE, and the 5' end of ORF3 was constructed in the parent Hib strain (RM7004) [3].
• The ORF3 protein of hepatitis E virus is a phosphoprotein that associates with the cytoskeleton [4].
• Immediately downstream from the previously isolated Treponema denticola ATCC 35405 prtB gene coding for a chymotrypsinlike protease activity, an open reading frame, ORF3, was identified which shared significant homology with the highly conserved domains (HCDs) of bacterial methyl-accepting chemotaxis proteins (MCPs) [5].

High impact information on ECs4082

• These results indicate that the impact of EspG/Orf3 on microtubule networks triggers the activation of the RhoA-ROCK signaling pathway via GEF-H1 activity [6].
• The predicted amino acid sequence of orf3 revealed no close homology to known proteins [7].
• Here we describe the function of the sixth gene, P450-3, and the cloning and functional analysis of a seventh gene, orf3, located at the left border of the gene cluster [7].
• Sequence analyses revealed the presence of three open reading frames (ORFs), designated as ORF-1, ORF-2, and ORF-3, and the structural genes of the heptaprenyl diphosphate synthase were proved to consist of ORF-1 (heps-1) and ORF-3 (heps-2) (Koike-Takeshita, A., Koyama, T., Obata, S., and Ogura, K. (1995) J. Biol. Chem. 270, 18396-18400) [8].
• Computer-assisted analysis of the DNA sequence revealed three putative open reading frames (ORFs), ORF1, ORF2, and ORF3 [9].

Chemical compound and disease context of ECs4082

• Escherichia coli expressing ORF3 showed (R)-enoyl-coenzyme A (CoA) hydratase activity, suggesting that (R)-3-hydroxyacyl-CoA monomer units are supplied via the (R)-specific hydration of enoyl-CoA in A. caviae [10].
• ORF3 has a predicted size of 21.4 kDa and 29% identity to triacylglycerol lipase of Psychrobacter immobilis [11].
• The aim of this study was to test for expression of a 900-bp open reading frame (ORF), ORF3, located at the 5' end of the mycocerosic acid synthase gene in Mycobacterium bovis BCG and to determine the nature of the ORF3 protein [12].
• The products of ORF2 and ORF3 show strong similarities with many beta-glucoside permeases of the phosphoenolpyruvate : beta-glucoside phosphotransferase systems (PTSs), such as Escherichia coli BglC, Bacillus subtilis BglP and Bacillus halodurans PTS Enzyme II [13].
• The amino acid sequence encoded by ORF3 (GraD) is 51.4% identical (69.9% similar) to that of StrD, a dTDP-glucose synthase from Streptomyces griseus [14].

Biological context of ECs4082

• To obtain downstream sequence data for ORF3, colony hybridization screening of the HindIII chlamydial DNA library was used to isolate a second recombinant plasmid (pH-11) that contained a 1.7-kilobase chlamydial DNA insert [15].
• The ORF3 probe also hybridized to a 540 bp transcript consistent with the size of ORF3 alone and supportive of the mutagenesis data of non-linkage [16].
• A 2.9 kb BclI fragment, previously shown to restore a wild-type phenotype to a glk deletion mutant that lacks the entire segment, contains two complete open reading frames that would encode proteins of 20.1 kDa (ORF2) and 33.1 kDa (ORF3) [17].
• A second EspG homolog, Orf3, is encoded on the EspC pathogenicity islet [18].
• The deduced lactoferrin binding protein A (LbpA) sequences from the two strains were found to be 99% identical, the LbpB sequences were 92% identical, and the ORF3 proteins were 98% identical [19].

Anatomical context of ECs4082

• Here, we show that the type III effectors, EspG and its homolog Orf3, trigger actin stress fiber formation and the destruction of the microtubule networks beneath adherent bacteria [6].
• Over a limited hydrophilic sequence stretch, bordered by putative transmembrane areas, ORF3 and ORF4 exhibit homology with subunits 4 and 1 of mitochondrial and plastid NADH-ubiquinol oxidoreductases, respectively [20].
• Analysis of RNA extracted from chlamydia-infected Vero cells detected ORF3-specific transcripts, from 20 h post-infection onwards, mainly as discrete RNA species of 1390 nucleotides comprising the downstream ORF4 sequence [21].

Associations of ECs4082 with chemical compounds

• One of these, designated wbgU (orf3), has been overexpressed and biochemically characterized to show that it encodes a uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) C4 epimerase, only the second microbial enzyme characterized to have this activity [22].
• These data suggest that ORF3 encodes a protein involved in the biosynthesis of ornithine, a constituent of phaseolotoxin [23].
• A lysine residue that is a binding site for pyridoxal phosphate and an arginine residue that is a binding site for the alpha-carboxylate group of the substrate are conserved in ORF3 [23].
• ORF3 was not essential for complementation; however, both the 23-kDa protein encoded by ORF3 and the predicted amino acid sequence of ORF4 showed homology to glutathione S-transferases [24].
• The ORF downstream of gcdA (ORF3) is followed by hgdA and hgdB coding for 2-hydroxyglutaryl-CoA dehydratase, the preceding enzyme of the pathway of glutamate fermentation [25].

Analytical, diagnostic and therapeutic context of ECs4082

• High performance liquid chromatography and gas chromatography-mass spectrometry analyses of the culture fluid of knock-out mutants identified GA1 and GA4, rather than GA3 and GA7, as the major C19-GA products, suggesting that orf3 encodes the GA4 1,2-desaturase [7].
• By site-specific mutagenesis, we have shown that one of the amino acid residues constituting the active centre of RuvC enzyme (Glu-66) and conserved in ORF3 (Glu-67) is essential for the nucleolytic activity of the M-operon gene product(s) [26].
• A Bg/II fragment containing ORF2 and ORF3 was cloned into pGK12, and the recombinant plasmid, pTRK135, was transformed into Lactobacillus acidophilus via electroporation [27].
• Northern blot analysis and promoter extension mapping indicated that ORF3 is expressed as a monocistronic operon from a promoter that resembles the Escherichia coli sigma 70 consensus promoter [28].
• However, plants inoculated with the aforementioned mutations did not develop symptoms, and Western blot analysis revealed markedly reduced expression of the movement protein (the product of ORF 3) [29].

References