scholarly journals A tyrosine O-prenyltransferase catalyses the first pathway-specific step in the biosynthesis of sirodesmin PL

Microbiology ◽  
2010 ◽  
Vol 156 (1) ◽  
pp. 278-286 ◽  
Author(s):  
Anika Kremer ◽  
Shu-Ming Li
Keyword(s):  
Escherichia Coli ◽  
Sequence Similarity ◽  
Leptosphaeria Maculans ◽  
Transfer Reactions ◽  
Indole Derivatives ◽  
Coding Region ◽  
Significant Sequence Similarity ◽  
Dimethylallyl Diphosphate ◽  
Apparent Homogeneity ◽  
Specific Step

A putative prenyltransferase gene sirD has been identified in the gene cluster encoding the biosynthesis of the phytotoxin sirodesmin PL in Leptosphaeria maculans. The gene product was found to comprise 449 aa, with a molecular mass of 51 kDa. In this study, the coding region of sirD was amplified by PCR from cDNA, cloned into pQE70, and overexpressed in Escherichia coli. The overproduced protein was purified to apparent homogeneity, and characterized biochemically. The dimeric recombinant SirD was found to catalyse the O-prenylation of l-Tyr in the presence of dimethylallyl diphosphate; this was demonstrated unequivocally by isolation and structural elucidation of the enzymic product. Therefore, SirD catalyses the first pathway-specific step in the biosynthesis of sirodesmin PL. K m values for l-Tyr and dimethylallyl diphosphate were determined as 0.13 and 0.17 mM, respectively. Interestingly, SirD was found to share significant sequence similarity with indole prenyltransferases, which catalyse prenyl transfer reactions onto different positions of indole rings. In contrast to indole prenyltransferases, which accept indole derivatives, but not Tyr or structures derived thereof, as substrates, SirD also prenylated l-Trp, resulting in the formation of 7-dimethylallyltryptophan. A K m value of 0.23 mM was determined for l-Trp. Turnover numbers of 1.0 and 0.06 S−1 were calculated for l-Tyr and l-Trp, respectively.

scholarly journals Synthetic promoter design in Escherichia coli based on a deep generative network

2020 ◽  
Vol 48 (12) ◽  
pp. 6403-6412 ◽  
Author(s):  
Ye Wang ◽  
Haochen Wang ◽  
Lei Wei ◽  
Shuailin Li ◽  
Liyang Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Predictive Model ◽  
De Novo ◽  
Sequence Similarity ◽  
Small Subset ◽  
Vast Number ◽  
Significant Sequence Similarity ◽  
E Coli ◽  
Synthetic Promoters ◽  
Naturally Occurring

Abstract Promoter design remains one of the most important considerations in metabolic engineering and synthetic biology applications. Theoretically, there are 450 possible sequences for a 50-nt promoter, of which naturally occurring promoters make up only a small subset. To explore the vast number of potential sequences, we report a novel AI-based framework for de novo promoter design in Escherichia coli. The model, which was guided by sequence features learned from natural promoters, could capture interactions between nucleotides at different positions and design novel synthetic promoters in silico. We combined a deep generative model that guides the search for artificial sequences with a predictive model to preselect the most promising promoters. The AI-designed promoters were optimized based on the promoter activity in E. coli and the predictive model. After two rounds of optimization, up to 70.8% of the AI-designed promoters were experimentally demonstrated to be functional, and few of them shared significant sequence similarity with the E. coli genome. Our work provided an end-to-end approach to the de novo design of novel promoter elements, indicating the potential to apply deep learning methods to de novo genetic element design.

Structures and reaction mechanisms of riboflavin synthases of eubacterial and archaeal origin

2005 ◽  
Vol 33 (4) ◽  
pp. 780-784 ◽  
Author(s):  
M. Fischer ◽  
W. Römisch ◽  
B. Illarionov ◽  
W. Eisenreich ◽  
A. Bacher
Keyword(s):  
Escherichia Coli ◽  
Reaction Mechanisms ◽  
Nmr Spectra ◽  
Common Ancestor ◽  
Sequence Similarity ◽  
Side Chain ◽  
Cd Spectra ◽  
Riboflavin Biosynthesis ◽  
Significant Sequence Similarity ◽  
E Coli

The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate as substrates. GTP is hydrolytically opened, converted into 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction and dephosphorylation. Condensation with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate leads to 6,7-dimethyl-8-ribityllumazine. The dismutation of 6,7-dimethyl-8-ribityllumazine catalysed by riboflavin synthase produces riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione. A pentacyclic adduct of two 6,7-dimethyl-8-ribityllumazines has been identified earlier as a catalytically competent reaction intermediate of the Escherichia coli enzyme. Acid quenching of reaction mixtures of riboflavin synthase of Methanococcus jannaschii, devoid of similarity to riboflavin synthases of eubacteria and eukaryotes, afforded a compound whose optical absorption and NMR spectra resemble that of the pentacyclic E. coli riboflavin synthase intermediate, whereas the CD spectra of the two compounds have similar envelopes but opposite signs. Each of the compounds could serve as a catalytically competent intermediate for the enzyme by which it was produced, but not vice versa. All available data indicate that the respective pentacyclic intermediates of the M. jannaschii and E. coli enzymes are diastereomers. Whereas the riboflavin synthase of M. jannaschii is devoid of similarity with those of eubacteria and eukaryotes, it has significant sequence similarity with 6,7-dimethyl-8-ribityllumazine synthases catalysing the penultimate step of riboflavin biosynthesis. 6,7-Dimethyl-8-ribityllumazine synthase and the archaeal riboflavin synthase appear to have diverged early in the evolution of Archaea from a common ancestor.

scholarly journals Analysis of the Function of a Putative 2,3-Diphosphoglyceric Acid-Dependent Phosphoglycerate Mutase fromBacillus subtilis

2000 ◽  
Vol 182 (14) ◽  
pp. 4121-4123 ◽  
Author(s):  
Claire L. Pearson ◽  
Charles A. Loshon ◽  
Lotte B. Pedersen ◽  
Barbara Setlow ◽  
Peter Setlow
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Spore Germination ◽  
Sequence Similarity ◽  
Phosphoglycerate Mutase ◽  
Significant Sequence Similarity ◽  
Low Level ◽  
Effect On Growth

ABSTRACT A Bacillus subtilis gene termed yhfRencodes the only B. subtilis protein with significant sequence similarity to 2,3-diphosphoglycerate-dependent phosphoglycerate mutases (dPGM). This gene is expressed at a low level during growth and sporulation, but deletion of yhfR had no effect on growth, sporulation, or spore germination and outgrowth. YhfR was expressed in and partially purified from Escherichia coli but had little if any PGM activity and gave no detectable PGM activity in B. subtilis. These data indicate thatB. subtilis does not require YhfR and most likely does not require a dPGM.

NorM, a Putative Multidrug Efflux Protein, of Vibrio parahaemolyticus and Its Homolog in Escherichia coli

1998 ◽  
Vol 42 (7) ◽  
pp. 1778-1782 ◽  
Author(s):  
Yuji Morita ◽  
Kazuyo Kodama ◽  
Sumiko Shiota ◽  
Tomoyuki Mine ◽  
Atsuko Kataoka ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vibrio Parahaemolyticus ◽  
Sequence Similarity ◽  
Multidrug Efflux ◽  
Chromosomal Dna ◽  
Efflux System ◽  
Significant Sequence Similarity ◽  
E Coli ◽  
Energy Dependent ◽  
Multidrug Efflux System

ABSTRACT We found that cells of Vibrio parahaemolyticus possess an energy-dependent efflux system for norfloxacin. We cloned a gene for a putative norfloxacin efflux protein from the chromosomal DNA ofV. parahaemolyticus by using an Escherichia coli mutant lacking the major multidrug efflux system AcrAB as the host and sequenced the gene (norM). Cells of E. coli transformed with a plasmid carrying the norMgene showed elevated energy-dependent efflux of norfloxacin. The transformants showed elevated resistance not only to norfloxacin and ciprofloxacin but also to the structurally unrelated compounds ethidium, kanamycin, and streptomycin. These results suggest that this is a multidrug efflux system. The hydropathy pattern of the deduced amino acid sequence of NorM suggested the presence of 12 transmembrane domains. The deduced primary structure of NorM showed 57% identity and 88% similarity with that of a hypothetical E. coli membrane protein, YdhE. No reported drug efflux protein in the sequence databases showed significant sequence similarity with NorM. Thus, NorM seems to be a novel type of multidrug efflux protein. We cloned the ydhE gene from E. coli. Cells ofE. coli transformed with the cloned ydhE gene showed elevated resistance to norfloxacin, ciprofloxacin, acriflavine, and tetraphenylphosphonium ion, but not to ethidium, when MICs were measured. Thus, it seems that NorM and YdhE differ somehow in substrate specificity.

scholarly journals Independent pseudogenizations and losses of sox15 during amniote diversification following asymmetric ohnolog evolution

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yusaku Ogita ◽  
Kei Tamura ◽  
Shuuji Mawaribuchi ◽  
Nobuhiko Takamatsu ◽  
Michihiko Ito
Keyword(s):  
Sequence Similarity ◽  
The Other ◽  
Vertebrate Evolution ◽  
Skeletal Muscle Regeneration ◽  
Cns Development ◽  
Placental Development ◽  
Relaxed Selection ◽  
Significant Sequence Similarity ◽  
Anuran Amphibians ◽  
Divergent Gene

Abstract Background Four ohnologous genes (sox1, sox2, sox3, and sox15) were generated by two rounds of whole-genome duplication in a vertebrate ancestor. In eutherian mammals, Sox1, Sox2, and Sox3 participate in central nervous system (CNS) development. Sox15 has a function in skeletal muscle regeneration and has little functional overlap with the other three ohnologs. In contrast, the frog Xenopus laevis and zebrafish orthologs of sox15 as well as sox1-3 function in CNS development. We previously reported that Sox15 is involved in mouse placental development as neofunctionalization, but is pseudogenized in the marsupial opossum. These findings suggest that sox15 might have evolved with divergent gene fates during vertebrate evolution. However, knowledge concerning sox15 in other vertebrate lineages than therian mammals, anuran amphibians, and teleost fish is scarce. Our purpose in this study was to clarify the fate and molecular evolution of sox15 during vertebrate evolution. Results We searched for sox15 orthologs in all vertebrate classes from agnathans to mammals by significant sequence similarity and synteny analyses using vertebrate genome databases. Interestingly, sox15 was independently pseudogenized at least twice during diversification of the marsupial mammals. Moreover, we observed independent gene loss of sox15 at least twice during reptile evolution in squamates and crocodile-bird diversification. Codon-based phylogenetic tree and selective analyses revealed an increased dN/dS ratio for sox15 compared to the other three ohnologs during jawed vertebrate evolution. Conclusions The findings revealed an asymmetric evolution of sox15 among the four ohnologs during vertebrate evolution, which was supported by the increased dN/dS values in cartilaginous fishes, anuran amphibians, and amniotes. The increased dN/dS value of sox15 may have been caused mainly by relaxed selection. Notably, independent pseudogenizations and losses of sox15 were observed during marsupial and reptile evolution, respectively. Both might have been caused by strong relaxed selection. The drastic gene fates of sox15, including neofunctionalization and pseudogenizations/losses during amniote diversification, might be caused by a release from evolutionary constraints.

scholarly journals Discriminating between JCPyV and BKPyV in Urinary Virome Data Sets

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1041
Author(s):  
Rita Mormando ◽  
Alan J. Wolfe ◽  
Catherine Putonti
Keyword(s):  
Jc Virus ◽  
Sequence Similarity ◽  
Bk Virus ◽  
Data Sets ◽  
Metagenomic Sequencing ◽  
Significant Sequence Similarity ◽  
Sequence Identity ◽  
Shotgun Metagenomic Sequencing ◽  
Urinary Microbiome ◽  
Six Genes

Polyomaviruses are abundant in the human body. The polyomaviruses JC virus (JCPyV) and BK virus (BKPyV) are common viruses in the human urinary tract. Prior studies have estimated that JCPyV infects between 20 and 80% of adults and that BKPyV infects between 65 and 90% of individuals by age 10. However, these two viruses encode for the same six genes and share 75% nucleotide sequence identity across their genomes. While prior urinary virome studies have repeatedly reported the presence of JCPyV, we were interested in seeing how JCPyV prevalence compares to BKPyV. We retrieved all publicly available shotgun metagenomic sequencing reads from urinary microbiome and virome studies (n = 165). While one third of the data sets produced hits to JCPyV, upon further investigation were we able to determine that the majority of these were in fact BKPyV. This distinction was made by specifically mining for JCPyV and BKPyV and considering uniform coverage across the genome. This approach provides confidence in taxon calls, even between closely related viruses with significant sequence similarity.

An intergenic G-rich region in Leishmania tarentolae kinetoplast maxicircle DNA is a pan-edited cryptogene encoding ribosomal protein S12

1992 ◽  
Vol 12 (1) ◽  
pp. 56-67
Author(s):  
D A Maslov ◽  
N R Sturm ◽  
B M Niner ◽  
E S Gruszynski ◽  
M Peris ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Sequence Similarity ◽  
Rich Region ◽  
Leishmania Tarentolae ◽  
Significant Sequence Similarity ◽  
The Family ◽  
Intergenic Regions ◽  
Ribosomal Protein S12

Six short G-rich intergenic regions in the maxicircle of Leishmania tarentolae are conserved in location and polarity in two other kinetoplastid species. We show here that G-rich region 6 (G6) represents a pan-edited cryptogene which contains at least two domains edited independently in a 3'-to-5' manner connected by short unedited regions. In the completely edited RNA, 117 uridines are added at 49 sites and 32 uridines are deleted at 13 sites, creating a translated 85-amino-acid polypeptide. Similar polypeptides are probably encoded by pan-edited G6 transcripts in two other species. The G6 polypeptide has significant sequence similarity to the family of S12 ribosomal proteins. A minicircle-encoded gRNA overlaps 12 editing sites in G6 mRNA, and chimeric gRNA/mRNA molecules were shown to exist, in agreement with the transesterification model for editing.

Yeast regulatory gene GAL3: carbon regulation; UASGal elements in common with GAL1, GAL2, GAL7, GAL10, GAL80, and MEL1; encoded protein strikingly similar to yeast and Escherichia coli galactokinases

1988 ◽  
Vol 8 (8) ◽  
pp. 3439-3447 ◽  
Author(s):  
W Bajwa ◽  
T E Torchia ◽  
J E Hopper
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Regulatory Gene ◽  
Data Bank ◽  
Noncoding Region ◽  
Striking Similarity ◽  
Coding Region ◽  
Reading Frame ◽  
Carbon Regulation ◽  
Sequence Similarities

GAL3 gene expression is required for rapid GAL4-mediated galactose induction of the galactose-melibiose regulon genes in Saccharomyces cerevisiae. Here we show by Northern (RNA) blot analysis that GAL3 gene expression is itself galactose inducible. Like the GAL1, GAL7, GAL10, and MEL1 genes, the GAL3 gene is severely glucose repressed. Like the MEL1 gene, but in contrast to the GAL1, GAL7, and GAL10 genes, GAL3 is expressed at readily detectable basal levels in cells grown in noninducing, nonrepressing media. We determined the sequence of the S. cerevisiae GAL3 gene and its 5'-noncoding region. Within the 5'-noncoding region of the GAL3 gene, we found two sequences similar to the UASGal elements of the other galactose-melibiose regulon genes. Deletion analysis indicated that only the most ATG proximal of these sequences is required for GAL3 expression. The coding region of GAL3 consists of a 1,275-base-pair open reading frame in the direction of transcription. A comparison of the deduced 425-amino-acid sequence with the protein data bank revealed three regions of striking similarity between the GAL3 protein and the GAL1-specified galactokinase of Saccharomyces carlsbergensis. One of these regions also showed striking similarity to sequences within the galactokinase protein of Escherichia coli. On the basis of these protein sequence similarities, we propose that the GAL3 protein binds a molecule identical to or structurally related to one of the substrates or products of the galactokinase-catalyzed reaction.

scholarly journals Comparative reactions of recombinant papaya ringspot viruses with chimeric coat protein (CP) genes and wild-type viruses on CP-transgenic papaya

2001 ◽  
Vol 82 (11) ◽  
pp. 2827-2836 ◽  
Author(s):  
Chu-Hui Chiang ◽  
Ju-Jung Wang ◽  
Fuh-Jyh Jan ◽  
Shyi-Dong Yeh ◽  
Dennis Gonsalves
Keyword(s):  
Coat Protein ◽  
Sequence Similarity ◽  
Transcriptional Gene Silencing ◽  
Papaya Ringspot Virus ◽  
Wild Type ◽  
Coding Region ◽  
Transgenic Papaya ◽  
Cp Gene ◽  
Post Transcriptional Gene Silencing

Transgenic papaya cultivars SunUp and Rainbow express the coat protein (CP) gene of the mild mutant of papaya ringspot virus (PRSV) HA. Both cultivars are resistant to PRSV HA and other Hawaii isolates through homology-dependent resistance via post-transcriptional gene silencing. However, Rainbow, which is hemizygous for the CP gene, is susceptible to PRSV isolates from outside Hawaii, while the CP-homozygous SunUp is resistant to most isolates but susceptible to the YK isolate from Taiwan. To investigate the role of CP sequence similarity in overcoming the resistance of Rainbow, PRSV HA recombinants with various CP segments of the YK isolate were constructed and evaluated on Rainbow, SunUp and non-transgenic papaya. Non-transgenic papaya were severely infected by all recombinants, but Rainbow plants developed a variety of symptoms. On Rainbow, a recombinant with the entire CP gene of YK caused severe symptoms, while recombinants with only partial YK CP sequences produced a range of milder symptoms. Interestingly, a recombinant with a YK segment from the 5′ region of the CP gene caused very mild, transient symptoms, whereas recombinants with YK segments from the middle and 3′ parts of the CP gene caused prominent and lasting symptoms. SunUp was resistant to all but two recombinants, which contained the entire CP gene or the central and 3′-end regions of the CP gene and the 3′ non-coding region of YK, and the resulting symptoms were mild. It is concluded that the position of the heterologous sequences in the recombinants influences their pathogenicity on Rainbow.

scholarly journals Phylogenetic structure of Shiga toxin-producing Escherichia coli O157:H7 from sub-lineage to SNPs

2021 ◽  
Author(s):  
Timothy J. Dallman ◽  
David R. Greig ◽  
Saheer E. Gharbia ◽  
Claire Jenkins
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Sequence Similarity ◽  
Evidence Base ◽  
Point Sources ◽  
Single Linkage ◽  
Phylogenetic Structure ◽  
Content Type ◽  
Geographically Dispersed ◽  
Cluster Threshold

Sequence similarity of pathogen genomes can infer the relatedness between isolates as the fewer genetic differences identified between pairs of isolates, the less time since divergence from a common ancestor. Clustering based on hierarchical single linkage clustering of pairwise SNP distances has been employed to detect and investigate outbreaks. Here, we evaluated the evidence-base for the interpretation of phylogenetic clusters of Shiga toxin-producing Escherichia coli (STEC) O157:H7. Whole genome sequences of 1193 isolates of STEC O157:H7 submitted to Public Health England between July 2015 and December 2016 were mapped to the Sakai reference strain. Hierarchical single linkage clustering was performed on the pairwise SNP difference between all isolates at descending distance thresholds. Cases with known epidemiological links fell within 5-SNP single linkage clusters. Five-SNP single linkage community clusters where an epidemiological link was not identified were more likely to be temporally and/or geographically related than sporadic cases. Ten-SNP single linkage clusters occurred infrequently and were challenging to investigate as cases were few, and temporally and/or geographically dispersed. A single linkage cluster threshold of 5-SNPs has utility for the detection of outbreaks linked to both persistent and point sources. Deeper phylogenetic analysis revealed that the distinction between domestic UK and imported isolates could be inferred at the sub-lineage level. Cases associated with domestically acquired infection that fall within clusters that are predominantly travel associated are likely to be caused by contaminated imported food.

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