scholarly journals Escherichia coli Open Reading Frame 696 Is idi, a Nonessential Gene Encoding Isopentenyl Diphosphate Isomerase

1999 ◽  
Vol 181 (15) ◽  
pp. 4499-4504 ◽  
Author(s):  
Frederick M. Hahn ◽  
Anthony P. Hurlburt ◽  
C. Dale Poulter

ABSTRACT Isopentenyl diphosphate isomerase catalyzes the interconversion of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). In eukaryotes, archaebacteria, and some bacteria, IPP is synthesized from acetyl coenzyme A by the mevalonate pathway. The subsequent isomerization of IPP to DMAPP activates the five-carbon isoprene unit for subsequent prenyl transfer reactions. In Escherichia coli, the isoprene unit is synthesized from pyruvate and glyceraldehyde-3-phosphate by the recently discovered nonmevalonate pathway. An open reading frame (ORF696) encoding a putative IPP isomerase was identified in the E. coli chromosome at 65.3 min. ORF696 was cloned into an expression vector; the 20.5 kDa recombinant protein was purified in three steps, and its identity as an IPP isomerase was established biochemically. The gene for IPP isomerase, idi, is not clustered with other known genes for enzymes in the isoprenoid pathway. E. coli FH12 was constructed by disruption of the chromosomal idi gene with the aminoglycoside 3′-phosphotransferase gene and complemented by the wild-type idi gene on plasmid pFMH33 with a temperature-sensitive origin of replication. FH12/pFMH33 was able to grow at the restrictive temperature of 44°C and FH12 lacking the plasmid grew on minimal medium, thereby establishing thatidi is a nonessential gene. Although theV max of the bacterial protein was 20-fold lower than that of its yeast counterpart, the catalytic efficiencies of the two enzymes were similar through a counterbalance inKm s. The E. coli protein requires Mg2+ or Mn2+ for activity. The enzyme contains conserved cysteine and glutamate active-site residues found in other IPP isomerases.

2004 ◽  
Vol 186 (23) ◽  
pp. 8156-8158 ◽  
Author(s):  
Sam J. Barkley ◽  
Shrivallabh B. Desai ◽  
C. Dale Poulter

ABSTRACT Open reading frame sll1556 in the cyanobacterium Synechocystis sp. strain 6803 encodes a putative type II isopentenyl diphosphate (IPP) isomerase. The His6-tagged protein was produced in Escherichia coli and purified by Ni2+ chromatography. The homotetrameric enzyme required NADPH, flavin mononucleotide, and Mg2+ for activity; K m IPP was 52 μM, and k cat IPP was 0.23 s−1.


2000 ◽  
Vol 353 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Narciso CAMPOS ◽  
Manuel RODRÍGUEZ-CONCEPCIÓN ◽  
Susanna SAURET-GÜETO ◽  
Francesca GALLEGO ◽  
Luisa-María LOIS ◽  
...  

Isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) constitute the basic building block of isoprenoids, a family of compounds that is extraordinarily diverse in structure and function. IPP and DMAPP can be synthesized by two independent pathways: the mevalonate pathway and the recently discovered 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway. Although the MEP pathway is essential in most eubacteria, algae and plants and has enormous biotechnological interest, only some of its steps have been determined. We devised a system suitable for the genetic analysis of the MEP pathway in Escherichia coli. A synthetic operon coding for yeast 5-diphosphomevalonate decarboxylase, human 5-phosphomevalonate kinase, yeast mevalonate kinase and E. coli isopentenyl diphosphate isomerase was incorporated in the chromosome of this bacterium. The expression of this operon allowed the synthesis of IPP and DMAPP from mevalonate added exogenously and complementation of lethal mutants of the MEP pathway. We used this system to show that the ygbP, ychB and ygbB genes are essential in E. coli and that the steps catalysed by the products of these genes belong to the trunk line of the MEP pathway.


2001 ◽  
Vol 183 (20) ◽  
pp. 6085-6094 ◽  
Author(s):  
Tohru Dairi ◽  
Yoshimitsu Hamano ◽  
Tomohisa Kuzuyama ◽  
Nobuya Itoh ◽  
Kazuo Furihata ◽  
...  

ABSTRACT A gene cluster containing the mevalonate pathway genes (open reading frame 2 [ORF2] to ORF7) for the formation of isopentenyl diphosphate and a geranylgeranyl diphosphate (GGDP) synthase gene (ORF1) had previously been cloned from Streptomyces griseolosporeus strain MF730-N6, a diterpenoid antibiotic, terpentecin (TP) producer (Y. Hamano, T. Dairi, M. Yamamoto, T. Kawasaki, K Kaneda, T. Kuzuyama, N. Itoh, and H. Seto, Biosci. Biotech. Biochem. 65:1627–1635, 2001). Sequence analysis in the upstream region of the cluster revealed seven new ORFs, ORF8 to ORF14, which were suggested to encode TP biosynthetic genes. We constructed two mutants, in which ORF11 and ORF12, which encode a protein showing similarities to eukaryotic diterpene cyclases (DCs) and a eubacterial pentalenene synthase, respectively, were inactivated by gene disruptions. The mutants produced no TP, confirming that these cyclase genes are essential for the production of TP. The two cyclase genes were also expressed in Streptomyces lividans together with the GGDP synthase gene under the control of theermE* constitutive promoter. The transformant produced a novel cyclic diterpenoid, ent-clerod-3,13(16),14-triene (terpentetriene), which has the same basic skeleton as TP. The two enzymes, each of which was overproduced in Escherichia coli and purified to homogeneity, converted GGDP into terpentetriene. To the best of our knowledge, this is the first report of a eubacterial DC.


2009 ◽  
Vol 75 (22) ◽  
pp. 7291-7293 ◽  
Author(s):  
Gopal Prasad Ghimire ◽  
Hei Chan Lee ◽  
Jae Kyung Sohng

ABSTRACT Putative hopanoid genes from Streptomyces peucetius were introduced into Escherichia coli to improve the production of squalene, an industrially important compound. High expression of hopA and hopB (encoding squalene/phytoene synthases) together with hopD (encoding farnesyl diphosphate synthase) yielded 4.1 mg/liter of squalene. This level was elevated to 11.8 mg/liter when there was also increased expression of dxs and idi, E. coli genes encoding 1-deoxy-d-xylulose 5-phosphate synthase and isopentenyl diphosphate isomerase.


2004 ◽  
Vol 70 (3) ◽  
pp. 1570-1575 ◽  
Author(s):  
Dae Heoun Baek ◽  
Jae Jun Song ◽  
Seok-Joon Kwon ◽  
Chung Park ◽  
Chang-Min Jung ◽  
...  

ABSTRACT A new thermostable dipeptidase gene was cloned from the thermophile Brevibacillus borstelensis BCS-1 by genetic complementation of the d-Glu auxotroph Escherichia coli WM335 on a plate containing d-Ala-d-Glu. Nucleotide sequence analysis revealed that the gene included an open reading frame coding for a 307-amino-acid sequence with an M r of 35,000. The deduced amino acid sequence of the dipeptidase exhibited 52% similarity with the dipeptidase from Listeria monocytogenes. The enzyme was purified to homogeneity from recombinant E. coli WM335 harboring the dipeptidase gene from B. borstelensis BCS-1. Investigation of the enantioselectivity (E) to the P1 and P1′ site of Ala-Ala revealed that the ratio of the specificity constant (k cat /Km ) for l-enantioselectivity to the P1 site of Ala-Ala was 23.4 � 2.2 [E = (k cat /Km ) l,d /(k cat /Km ) d,d ], while the d-enantioselectivity to the P1′ site of Ala-Ala was 16.4 � 0.5 [E = (k cat /Km ) l,d /(k cat /Km ) l,l ] at 55�C. The enzyme was stable up to 55�C, and the optimal pH and temperature were 8.5 and 65�C, respectively. The enzyme was able to hydrolyze l-Asp-d-Ala, l-Asp-d-AlaOMe, Z-d-Ala-d-AlaOBzl, and Z-l-Asp-d-AlaOBzl, yet it could not hydrolyze d-Ala-l-Asp, d-Ala-l-Ala, d-AlaNH2, and l-AlaNH2. The enzyme also exhibited β-lactamase activity similar to that of a human renal dipeptidase. The dipeptidase successfully synthesized the precursor of the dipeptide sweetener Z-l-Asp-d-AlaOBzl.


1999 ◽  
Vol 181 (23) ◽  
pp. 7256-7265 ◽  
Author(s):  
Birgitta Esberg ◽  
Hon-Chiu Eastwood Leung ◽  
Ho-Ching Tiffany Tsui ◽  
Glenn R. Björk ◽  
Malcolm E. Winkler

ABSTRACT The tRNA of the miaB2508::Tn10dCm mutant of Salmonella typhimurium is deficient in the methylthio group of the modified nucleosideN 6-(4-hydroxyisopentenyl)-2-methylthioadenosine (ms2io6A37). By sequencing, we found that the Tn10dCm of this strain had been inserted into thef474 (yleA) open reading frame, which is located close to the nag locus in both S. typhimurium and Escherichia coli. By complementation of the miaB2508::Tn10dCm mutation with a minimal subcloned f474 fragment, we showed thatf474 could be identified as the miaB gene, which is transcribed in the counterclockwise direction on the bacterial chromosome. Transcriptional studies revealed two promoters upstream ofmiaB in E. coli and S. typhimurium. A Rho-independent terminator was identified downstream of themiaB gene, at which the majority (96%) of themiaB transcripts terminate in E. coli, showing that the miaB gene is part of a monocistronic operon. A highly conserved motif with three cysteine residues was present in MiaB. This motif resembles iron-binding sites in other proteins. Only a weak similarity to an AdoMet-binding site was found, favoring the idea that the MiaB protein is involved in the thiolation step and not in the methylating reaction of ms2i(o)6A37 formation.


2012 ◽  
Vol 58 (1) ◽  
pp. 112-115 ◽  
Author(s):  
Zhenwen Zhou ◽  
Ruili Guan ◽  
Yiyu Yang ◽  
Ling Chen ◽  
Jie Fu ◽  
...  

New Delhi metallo-β-lactamase-1 (NDM-1) is a novel type of metallo-β-lactamase (MBL) responsible for bacterial resistance to β-lactam antibiotics. Acinetobacter junii was previously shown to possess a MBL phenotype; however, the genes responsible for this phenotype were not identified. In this study, we reported the identification of NDM-1 gene in a clinical isolate of A. junii from a child patient in China, which was resistant to all β-lactams except aztreonam but sensitive to aminoglycosides and quinolones. The cloned NDM-1 gene contained an open reading frame of 813 bp and had a nucleotide sequence 99.9% identical (812/813) to reported NDM-1 genes carried by Acinetobacter baumannii , Enterococcus faecium , Escherichia coli , and Klebsiella pneumoniae . Recombinant NDM-1 protein was successfully expressed in E. coli BL21, and antibiotic sensitivities of the NDM-1-producing E. coli were largely similar to the A. junii 1454 isolate. The findings of this study raise attention to the emergence and spread of NDM-1-carrying bacteria in China.


1990 ◽  
Vol 68 (1) ◽  
pp. 123-137 ◽  
Author(s):  
Krishna G. Peri ◽  
Hughes Goldie ◽  
E. Bruce Waygood

Three enzymes are required for N-acetylglucosamine (NAG) utilization in Escherichia coli: enzyme IInag (gene nagE), N-acetylglucosamine-6-phosphate deacetylase (gene nagA), and glucosamine-6-phosphate isomerase (gene nagB). The three genes are located near 16 min on the E. coli chromosome. A strain of E. coli, KPN9, incapable of utilizing N-acetylglucosamine, was used to screen a genomic library of E. coli for a complementing recombinant colicin E1 plasmid that allowed for growth on N-acetylglucosamine. Plasmid pLC5-21 was found to contain all three known nag genes on a 5.7-kilobase (5.7-kb) fragment of DNA. The products of these nag genes were identified by complementation of E. coli strains with mutations in nagA, nagB, and nagE. The gene products from the 5.7-kb fragment were identified by [35S]methionine-labelled maxicells and autoradiography of sodium dodecyl sulphate – polyacrylamide electrophoresis gels. The gene products had the following relative masses (Mrs: nagE, 62 000; nagA, 45 000; nagB, 29 000. In addition, another product of Mr 44 000 was detected. The genes have been sequenced to reveal an additional open reading frame (nagC), a putative catabolite activator protein binding site that may control nagB and nagE, putative rho-independent terminator sites for nagB and nagE, and sequence homologies for RNA polymerase binding sites preceding each of the open reading frames, except for nagA. The calculated molecular weights (MWs) of the gene products derived from the sequence are as follows: nagA, 40 954; nagB, 29 657; nagC, 44 664; nagE, 68 356. No role is known for nagC, although a number of regulatory roles appear to be plausible. No obvious transcriptional termination site distal to nagC was found and another open reading frame begins after nagC. This gene, nagD, was isolated separately from pLC5-21, and the sequence revealed a protein with a calculated MW of 27 181. The nagD gene is followed by repetitive extragenic palindromic sequences. The nag genes appear to be organized in an operon: [Formula: see text]Key words: N-acetylglucosamine, N-acetylglucosamine-6-P deacetylase, glucosamine-6-P isomerase, repetitive extragenic palindromic sequences, catabolite repression.


2005 ◽  
Vol 187 (6) ◽  
pp. 2030-2037 ◽  
Author(s):  
Tomokuni Abe ◽  
Eiji Masai ◽  
Keisuke Miyauchi ◽  
Yoshihiro Katayama ◽  
Masao Fukuda

ABSTRACT Vanillate and syringate are converted into protocatechuate (PCA) and 3-O-methylgallate (3MGA), respectively, by O-demethylases in Sphingomonas paucimobilis SYK-6. PCA is further degraded via the PCA 4,5-cleavage pathway, while 3MGA is degraded through multiple pathways in which PCA 4,5-dioxygenase (LigAB), 3MGA 3,4-dioxygenase (DesZ), and an unidentified 3MGA O-demethylase and gallate dioxygenase are participants. For this study, we isolated a 4.7-kb SmaI fragment that conferred on Escherichia coli the activity required for the conversion of vanillate to PCA. The nucleotide sequence of this fragment revealed an open reading frame of 1,413 bp (ligM), the deduced amino acid sequence of which showed 49% identity with that of the tetrahydrofolate (H4folate)-dependent syringate O-demethylase gene (desA). The metF and ligH genes, which are thought to be involved in H4folate-mediated C1 metabolism, were located just downstream of ligM. The crude LigM enzyme expressed in E. coli converted vanillate and 3MGA to PCA and gallate, respectively, with similar specific activities, and only in the presence of H4folate; however, syringate was not a substrate for LigM. The disruption of ligM led to significant growth retardation on both vanillate and syringate, indicating that ligM is involved in the catabolism of these substrates. The ability of the ligM mutant to transform vanillate was markedly decreased, and this mutant completely lost the 3MGA O-demethylase activity. A ligM desA double mutant completely lost the ability to transform vanillate, thus indicating that desA also contributes to vanillate degradation. All of these results indicate that ligM encodes vanillate/3MGA O-demethylase and plays an important role in the O demethylation of vanillate and 3MGA, respectively.


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