scholarly journals Identification and analysis of proton-translocating pyrophosphatases in the methanogenic archaeonMethanosarcina mazei

Archaea ◽  
2002 ◽  
Vol 1 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Sebastian Bäumer ◽  
Sabine Lentes ◽  
Gerhard Gottschalk ◽  
Uwe Deppenmeier

Analysis of genome sequence data from the methanogenic archaeonMethanosarcina mazeiGö1 revealed the existence of two open reading frames encoding proton-translocating pyrophosphatases (PPases). These open reading frames are linked by a 750-bp intergenic region containing TC-rich stretches and are transcribed in opposite directions. The corresponding polypeptides are referred to as Mvp1 and Mvp2 and consist of 671 and 676 amino acids, respectively. Both enzymes represent extremely hydrophobic, integral membrane proteins with 15 predicted transmembrane segments and an overall amino acid sequence similarity of 50.1%. Multiple sequence alignments revealed that Mvp1 is closely related to eukaryotic PPases, whereas Mvp2 shows highest homologies to bacterial PPases. Northern blot experiments with RNA from methanol-grown cells harvested in the mid-log growth phase indicated that only Mvp2 was produced under these conditions. Analysis of washed membranes showed that Mvp2 had a specific activity of 0.34 U mg (protein)–1. Proton translocation experiments with inverted membrane vesicles prepared from methanol-grown cells showed that hydrolysis of 1 mol of pyrophosphate was coupled to the translocation of about 1 mol of protons across the cytoplasmic membrane. Appropriate conditions formvp1 expression could not be determined yet. The pyrophosphatases ofM. mazeiGö1 represent the first examples of this enzyme class in methanogenic archaea and may be part of their energy-conserving system. Abbreviations: DCCD,N,N′-dicyclohexylcarbodiimide; PPase, inorganic pyrophosphatase; PPi, inorganic pyrophosphate; Δp, proton motive force.

2016 ◽  
Vol 4 (4) ◽  
Author(s):  
Elham Ehsani ◽  
Israel Barrantes ◽  
Johanna Vandermaesen ◽  
Robert Geffers ◽  
Michael Jarek ◽  
...  

We report here the draft genome sequence ofAeromonassp. strain EERV15 isolated from sand filter. The organism most closely related toAeromonassp. EERV15 isAeromonas veroniiB565, with an average 83% amino acid sequence similarity of putatively encoded protein open reading frames.


2020 ◽  
Vol 100 (2) ◽  
pp. 359-367
Author(s):  
Tiantian Gu ◽  
Guoqin Li ◽  
Yong Tian ◽  
Li Chen ◽  
Xinsheng Wu ◽  
...  

Melanoma differentiation-associated gene 5 (MDA5) is an important cytoplasmic RNA sensor that detects viral double-stranded RNA in innate immunity. The objective of this study was to characterize the structure and function of the MDA5 gene in the duck. In this study, full-length duck MDA5 (duMDA5) complementary DNA (cDNA) was obtained using the reverse transcription-polymerase chain reaction and rapid amplification of the cDNA ends. The cDNA consisted of a 123 nucleotide 5′ untranslated region (UTR), a 735 nucleotide 3′ UTR, and a 3012 nucleotide open-reading frame, encoding 1003 amino acids. Multiple sequence alignments showed that duMDA5 had 91.18% and 83.11% amino acid sequence similarity with geese and chicken MDA5, respectively, as well as 59.76%–61.26% sequence identity with mammalian homologs. Phylogenetic analysis demonstrated that MDA5 has been highly conserved throughout vertebrate evolution. Quantitative real-time polymerase chain reaction analysis indicated that the duMDA5 mRNA is scarcely detected in healthy tissues and the highest relative transcript level of duMDA5 was induced during poly(I:C) stimulation. Furthermore, knockdown duMDA5 significantly inhibited the transcription of poly(I:C)-induced beta interferons, nuclear factor kappa-B, interferon regulatory factor 7, translocated intimin receptor domain-containing adaptor protein inducing beta interferons, interferon-induced GTP-binding protein, signal transducer and activator of transcription 1 and 2 mRNA. Taken together, these results suggest that duMDA5 is an important receptor for inducing antiviral activity in the duck’s innate immune response.


2000 ◽  
Vol 182 (13) ◽  
pp. 3784-3793 ◽  
Author(s):  
Vincent J. J. Martin ◽  
William W. Mohn

ABSTRACT We have cloned and sequenced the dit gene cluster encoding enzymes of the catabolic pathway for abietane diterpenoid degradation by Pseudomonas abietaniphila BKME-9. Thedit gene cluster is located on a 16.7-kb DNA fragment containing 13 complete open reading frames (ORFs) and 1 partial ORF. The genes ditA1A2A3 encode the α and β subunits and the ferredoxin of the dioxygenase which hydroxylates 7-oxodehydroabietic acid to 7-oxo-11,12-dihydroxy-8,13-abietadien acid. The dioxygenase mutant strain BKME-941 (ditA1::Tn5) did not grow on nonaromatic abietanes, and transformed palustric and abietic acids to 7-oxodehydroabietic acid in cell suspension assays. Thus, nonaromatic abietanes are aromatized prior to further degradation. Catechol 2,3-dioxygenase activity of xylEtranscriptional fusion strains showed induction of ditA1and ditA3 by abietic, dehydroabietic, and 7-oxodehydroabietic acids, which support the growth of strain BKME-9, as well as by isopimaric and 12,14-dichlorodehydroabietic acids, which are diterpenoids that do not support the growth of strain BKME-9. In addition to the aromatic-ring-hydroxylating dioxygenase genes, thedit cluster includes ditC, encoding an extradiol ring cleavage dioxygenase, and ditR, encoding an IclR-type transcriptional regulator. Although ditR is not strictly required for the growth of strain BKME-9 on abietanes, aditR::Kmr mutation in aditA3::xylE reporter strain demonstrated that it encodes an inducer-dependent transcriptional activator of ditA3. An ORF with sequence similarity to genes encoding permeases (ditE) is linked with genes involved in abietane degradation.


2016 ◽  
Vol 198 (9) ◽  
pp. 1393-1400 ◽  
Author(s):  
Guangyu E. Chen ◽  
Andrew Hitchcock ◽  
Philip J. Jackson ◽  
Roy R. Chaudhuri ◽  
Mark J. Dickman ◽  
...  

ABSTRACTThe major photopigment of the cyanobacteriumAcaryochloris marinais chlorophylld, while its direct biosynthetic precursor, chlorophylla, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic phototrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosynthesis. Two unrelated classes of 8-vinyl reductase involved in the biosynthesis of chlorophylls are known to exist, BciA and BciB. The genome ofAcaryochloris marinacontains open reading frames (ORFs) encoding proteins displaying high sequence similarity to BciA or BciB, although they are annotated as genes involved in transcriptional control (nmrA) and methanogenesis (frhB), respectively. These genes were introduced into an 8-vinyl chlorophylla-producing ΔbciBstrain ofSynechocystissp. strain PCC 6803, and both were shown to restore synthesis of the pigment with an ethyl group at C-8, demonstrating their activities as 8-vinyl reductases. We propose thatnmrAandfrhBbe reassigned asbciAandbciB, respectively; transcript and proteomic analysis ofAcaryochloris marinareveal that bothbciAandbciBare expressed and their encoded proteins are present in the cell, possibly in order to ensure that all synthesized chlorophyll pigment carries an ethyl group at C-8. Potential reasons for the presence of two 8-vinyl reductases in this strain, which is unique for cyanobacteria, are discussed.IMPORTANCEThe cyanobacteriumAcaryochloris marinais the best-studied phototrophic organism that uses chlorophylldfor photosynthesis. Unique among cyanobacteria sequenced to date, its genome contains ORFs encoding two unrelated enzymes that catalyze the reduction of the C-8 vinyl group of a precursor molecule to an ethyl group. Carrying a reduced C-8 group may be of particular importance to organisms containing chlorophylld. Plant genomes also contain orthologs of both of these genes; thus, the bacterial progenitor of the chloroplast may also have contained bothbciAandbciB.


1992 ◽  
Vol 288 (1) ◽  
pp. 117-121 ◽  
Author(s):  
E P Ko ◽  
H Akatsuka ◽  
H Moriyama ◽  
A Shinmyo ◽  
Y Hata ◽  
...  

To elucidate the reaction mechanism of xylanase, the identification of amino acids essential for its catalysis is of importance. Studies have indicated the possibility that the reaction mechanism of xylanase is similar to that of hen's egg lysozyme, which involves acidic amino acid residues. On the basis of this assumption, together with the three-dimensional structure of Bacillus pumilus xylanase and its amino acid sequence similarity to other xylanases of different origins, three acidic amino acids, namely Asp-21, Glu-93 and Glu-182, were selected for site-directed mutagenesis. The Asp residue was altered to either Ser or Glu, and the Glu residues to Ser or Asp. The purified mutant xylanases D21E, D21S, E93D, E93S, E182D and E182S showed single protein bands of about 26 kDa on SDS/PAGE. C.d. spectra of these mutant enzymes show no effect on the secondary structure of xylanase, except that of D21E, which shows a little variation. Furthermore, mutations of Glu-93 and Glu-182 resulted in a drastic decrease in the specific activity of xylanase as compared with mutation of Asp-21. On the basis of these results we propose that Glu-93 and Glu-182 are the best candidates for the essential catalytic residues of xylanase.


2020 ◽  
Vol 6 (10) ◽  
Author(s):  
Ao Li ◽  
Elisabeth Laville ◽  
Laurence Tarquis ◽  
Vincent Lombard ◽  
David Ropartz ◽  
...  

Mannoside phosphorylases are involved in the intracellular metabolization of mannooligosaccharides, and are also useful enzymes for the in vitro synthesis of oligosaccharides. They are found in glycoside hydrolase family GH130. Here we report on an analysis of 6308 GH130 sequences, including 4714 from the human, bovine, porcine and murine microbiomes. Using sequence similarity networks, we divided the diversity of sequences into 15 mostly isofunctional meta-nodes; of these, 9 contained no experimentally characterized member. By examining the multiple sequence alignments in each meta-node, we predicted the determinants of the phosphorolytic mechanism and linkage specificity. We thus hypothesized that eight uncharacterized meta-nodes would be phosphorylases. These sequences are characterized by the absence of signal peptides and of the catalytic base. Those sequences with the conserved E/K, E/R and Y/R pairs of residues involved in substrate binding would target β-1,2-, β-1,3- and β-1,4-linked mannosyl residues, respectively. These predictions were tested by characterizing members of three of the uncharacterized meta-nodes from gut bacteria. We discovered the first known β-1,4-mannosyl-glucuronic acid phosphorylase, which targets a motif of the Shigella lipopolysaccharide O-antigen. This work uncovers a reliable strategy for the discovery of novel mannoside-phosphorylases, reveals possible interactions between gut bacteria, and identifies a biotechnological tool for the synthesis of antigenic oligosaccharides.


Author(s):  
Jun Wang ◽  
Pu-Feng Du ◽  
Xin-Yu Xue ◽  
Guang-Ping Li ◽  
Yuan-Ke Zhou ◽  
...  

Abstract Summary Many efforts have been made in developing bioinformatics algorithms to predict functional attributes of genes and proteins from their primary sequences. One challenge in this process is to intuitively analyze and to understand the statistical features that have been selected by heuristic or iterative methods. In this paper, we developed VisFeature, which aims to be a helpful software tool that allows the users to intuitively visualize and analyze statistical features of all types of biological sequence, including DNA, RNA and proteins. VisFeature also integrates sequence data retrieval, multiple sequence alignments and statistical feature generation functions. Availability and implementation VisFeature is a desktop application that is implemented using JavaScript/Electron and R. The source codes of VisFeature are freely accessible from the GitHub repository (https://github.com/wangjun1996/VisFeature). The binary release, which includes an example dataset, can be freely downloaded from the same GitHub repository (https://github.com/wangjun1996/VisFeature/releases). Contact [email protected] or [email protected] Supplementary information Supplementary data are available at Bioinformatics online.


2000 ◽  
Vol 182 (21) ◽  
pp. 6066-6074 ◽  
Author(s):  
Andrew M. Kropinski

ABSTRACT Temperate bacteriophage D3, a member of the virus familySiphoviridae, is responsible for serotype conversion in its host, Pseudomonas aeruginosa. The complete sequence of the double-stranded DNA genome has been determined. The 56,426 bp contains 90 putative open reading frames (ORFs) and four genes specifying tRNAs. The latter are specific for methionine (AUG), glycine (GGA), asparagine (AAC), and threonine (ACA). The tRNAs may function in the translation of certain highly expressed proteins from this relatively AT-rich genome. D3 proteins which exhibited a high degree of sequence similarity to previously characterized phage proteins included the portal, major head, tail, and tail tape measure proteins, endolysin, integrase, helicase, and NinG. The layout of genes was reminiscent of lambdoid phages, with the exception of the placement of the endolysin gene, which parenthetically also lacked a cognate holin. The greatest sequence similarity was found in the morphogenesis genes to coliphages HK022 and HK97. Among the ORFs was discovered the gene encoding the fucosamine O-acetylase, which is in part responsible for the serotype conversion events.


2019 ◽  
Vol 36 (7) ◽  
pp. 2047-2052 ◽  
Author(s):  
Ha Young Kim ◽  
Dongsup Kim

Abstract Motivation Accurate prediction of the effects of genetic variation is a major goal in biological research. Towards this goal, numerous machine learning models have been developed to learn information from evolutionary sequence data. The most effective method so far is a deep generative model based on the variational autoencoder (VAE) that models the distributions using a latent variable. In this study, we propose a deep autoregressive generative model named mutationTCN, which employs dilated causal convolutions and attention mechanism for the modeling of inter-residue correlations in a biological sequence. Results We show that this model is competitive with the VAE model when tested against a set of 42 high-throughput mutation scan experiments, with the mean improvement in Spearman rank correlation ∼0.023. In particular, our model can more efficiently capture information from multiple sequence alignments with lower effective number of sequences, such as in viral sequence families, compared with the latent variable model. Also, we extend this architecture to a semi-supervised learning framework, which shows high prediction accuracy. We show that our model enables a direct optimization of the data likelihood and allows for a simple and stable training process. Availability and implementation Source code is available at https://github.com/ha01994/mutationTCN. Supplementary information Supplementary data are available at Bioinformatics online.


2000 ◽  
Vol 182 (21) ◽  
pp. 6123-6129 ◽  
Author(s):  
Matthias Contzen ◽  
Andreas Stolz

ABSTRACT The genes for two different protocatechuate 3,4-dioxygenases (P34Os) were cloned from the 4-sulfocatechol-degrading bacteriumAgrobacterium radiobacter strain S2 (DSMZ 5681). ThepcaH1G1 genes encoded a P34O (P34O-I) which oxidized protocatechuate but not 4-sulfocatechol. These genes were part of a protocatechuate-degradative operon which strongly resembled the isofunctional operon from the protocatechuate-degrading strainAgrobacterium tumefaciens A348 described previously by D. Parke (FEMS Microbiol. Lett. 146:3–12, 1997). The second P34O (P34O-II), encoded by the pcaH2G2 genes, was functionally expressed and shown to convert protocatechuate and 4-sulfocatechol. A comparison of the deduced amino acid sequences of PcaH-I and PcaH-II, and of PcaG-I and PcaG-II, with each other and with the corresponding sequences from the P34Os, from other bacterial genera suggested that the genes for the P34O-II were obtained by strain S2 by lateral gene transfer. The genes encoding the P34O-II were found in a putative operon together with two genes which, according to sequence alignments, encoded transport proteins. Further downstream from this putative operon, two open reading frames which code for a putative regulator protein of the IclR family and a putative 3-carboxymuconate cycloisomerase were identified.


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