Only one catalase, katG, is detectable in Rhizobium etli, and is encoded along with the regulator OxyR on a plasmid replicon

Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1165-1176 ◽  
Author(s):  
María del Carmen Vargas ◽  
Sergio Encarnación ◽  
Araceli Dávalos ◽  
Agustín Reyes-Pérez ◽  
Yolanda Mora ◽  
...  
Keyword(s):  
Peroxidase Activity ◽  
Proteome Analysis ◽  
Sublethal Concentration ◽  
Dual Function ◽  
Compensatory Mechanism ◽  
Sequence Motifs ◽  
Rhizobium Etli ◽  
Multiple Sequence ◽  
Subsequent Exposure ◽  
Catalase Peroxidase

The plasmid-borne Rhizobium etli katG gene encodes a dual-function catalase-peroxidase (KatG) (EC 1.11.1.7) that is inducible and heat-labile. In contrast to other rhizobia, katG was shown to be solely responsible for catalase and peroxidase activity in R. etli. An R. etli mutant that did not express catalase activity exhibited increased sensitivity to hydrogen peroxide (H2O2). Pre-exposure to a sublethal concentration of H2O2 allowed R. etli to adapt and survive subsequent exposure to higher concentrations of H2O2. Based on a multiple sequence alignment with other catalase-peroxidases, it was found that the catalytic domains of the R. etli KatG protein had three large insertions, two of which were typical of KatG proteins. Like the katG gene of Escherichia coli, the R. etli katG gene was induced by H2O2 and was important in sustaining the exponential growth rate. In R. etli, KatG catalase-peroxidase activity is induced eightfold in minimal medium during stationary phase. It was shown that KatG catalase-peroxidase is not essential for nodulation and nitrogen fixation in symbiosis with Phaseolus vulgaris, although bacteroid proteome analysis indicated an alternative compensatory mechanism for the oxidative protection of R. etli in symbiosis. Next to, and divergently transcribed from the catalase promoter, an ORF encoding the regulator OxyR was found; this is the first plasmid-encoded oxyR gene described so far. Additionally, the katG promoter region contained sequence motifs characteristic of OxyR binding sites, suggesting a possible regulatory mechanism for katG expression.

scholarly journals Regulation of Brucella abortusCatalase

2000 ◽  
Vol 68 (7) ◽  
pp. 3861-3866 ◽  
Author(s):  
Jeong-a Kim ◽  
Zengyu Sha ◽  
John E. Mayfield
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Pathogenic Bacteria ◽  
Sublethal Concentration ◽  
Subsequent Exposure ◽  
Catalase Peroxidase ◽  
Increased Sensitivity ◽  
Analysis Survival ◽  
Hostile Environments

ABSTRACT All aerobic organisms have mechanisms that protect against oxidative compounds. Catalase, peroxidase, superoxide dismutase, glutathione, and thioredoxin are widely distributed in many taxa and constitute elements of a nearly ubiquitous antioxidant metabolic strategy. Interestingly, the regulatory mechanisms that control these elements are rather different depending on the nature of the oxidative stress and the organism. Catalase is well documented to play an important role in protecting cells from oxidative stress. In particular, pathogenic bacteria seem to use this enzyme as a defensive tool against attack by the host. To investigate the significance of catalase in hostile environments, we made catalase deletion mutations in two different B. abortus strains and used two-dimensional gel analysis, survival tests, and adaptation experiments to explore the behavior and role of catalase under several oxidative stress conditions. These studies show that B. abortus strains that do not express catalase activity exhibit increased sensitivity to hydrogen peroxide. We also demonstrate that catalase expression is regulated in this species, and that preexposure to a sublethal concentration of hydrogen peroxide allows B. abortus to adapt so as to survive subsequent exposure to higher concentrations of hydrogen peroxide.

scholarly journals The catalase-peroxidase of Synechococcus PCC 7942: purification, nucleotide sequence analysis and expression in Escherichia coli

1996 ◽  
Vol 316 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Michinori MUTSUDA ◽  
Takahiro ISHIKAWA ◽  
Toru TAKEDA ◽  
Shigeru SHIGEOKA
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Molecular Mass ◽  
Peroxidase Activity ◽  
Catalase Activity ◽  
Native Enzyme ◽  
Nucleotide Sequence Analysis ◽  
Synechococcus Pcc 7942 ◽  
Catalase Peroxidase ◽  
Pcc 7942

Synechococcus PCC 7942, a cyanobacterium, possesses catalase–peroxidase as the sole hydrogen peroxide-scavenging system. The enzyme has been purified to electrophoretic homogenenity from the cells. The native enzyme had a molecular mass of 150 kDa and was composed of two identical subunits of molecular mass 79 kDa. The apparent Km value of the catalase activity for H2O2 was 4.2±0.27 mM and the kcat value was 2.6×104 s-1. The enzyme contained high catalase activity and an appreciable peroxidase activity with o-dianisidine and pyrogallol. The catalase activity was not inhibited by 3-amino-1,2,4-triazole but by KCN and NaN3 (apparent Ki values 19.3±0.84 and 20.2±0.95 μM respectively). The enzyme showed an absorption spectrum of typical protohaem and contained one protohaem molecule per dimer. The gene encoding catalase–peroxidase was cloned from the chromosomal DNA of Synechococcus PCC 7942. A 2160 bp open reading frame (ORF), coding a catalase–peroxidase of 720 amino acid residues (approx. 79.9 kDa), was observed. The deduced amino acid sequence coincided with that of the N-terminus of the purified enzyme and showed a remarkable similarity to those of a family of catalase–peroxidases of prokaryotic cells. Escherichia coli BL21(DE3)plysS, harbouring a recombinant plasmid containing the catalase–peroxidase gene, produced a large amount of proteins that co-migrated on SDS/PAGE with the native enzyme. The recombinant enzyme showed the same ratio of catalase activity to peroxidase activity with o-dianisidine and the same Km for H2O2 as the native enzyme.

scholarly journals Effect of fungicides on the enzymatic activity of the antioxidant system and the chlorophyll content in lupine plants during seed dressing

2020 ◽  
pp. 3-6
Author(s):  
O. Borzykh ◽  
O. Tsurkan ◽  
L. Chervyakova ◽  
T. Panchenko
Keyword(s):  
Analytical Chemistry ◽  
Chlorophyll Content ◽  
Peroxidase Activity ◽  
Catalase Activity ◽  
Control Level ◽  
Growth Stages ◽  
Enzymatic System ◽  
Initial Growth ◽  
Seed Dressing ◽  
Catalase Peroxidase

Goal. The effect of fungicides on the dynamics of the activity of peroxidase, catalase (CAT) and chlorophyll content in lupine plants during seed dressing has been established. Methods. Laboratory and vegetation researches were conducted in the laboratory of analytical chemistry of pesticides of the Institute of Plant Protection. Yellow lupine (Lupinus luteus L.), variety Obriy has been grown. The objects of research were fungicides triticonazol (40 g/t) and its combination with prochloraz (120 g/t). Determination of the content of fungicides in plants was carried out using chromatographic methods according to officially approved methods and me­thods developed in the laboratory of analytical chemistry of pesticides. Chlorophyll content and peroxidase activity were measured by colorimetric method, catalase activity — by titrimetric method. Results. According to the research results, the varying sensitivity of the enzymatic system of antioxidant defense (catalase, peroxidase) in response to seed dressing by fungicides was recorded. It showed that on the 10th day after sowing, content of triticonazol in plants was 0.8 mg/kg, and the peroxidase activity was similar to that in untreated plants. Subsequently, against the background of a decrease in the content of the active substance, a gradual activation of the enzyme was observed. Catalase activity also gradually increased beginning from the 14th day, and on the 30th day it exceeded the corresponding control indicator by 40%. When using a combination of triticonazol with prochloraz, the disturbance in the balance of peroxidase catalase was more significant. However, by the phase of 7—8 leaves, with a minimal total content of fungicides (0.38 mg/kg), the enzyme activity approached the control level, which is associated with the restoration of plant homeostasis and the formation of its adaptive potential under stress conditions. The stimulating effect of these fungicides on chlorophyll content at the initial growth stages of lupine was established. The chlorophyll concentration in fungicides-treated plants exceeded the control indicator by 11—29%. Conclusions. The use of systemic triazole fungicides to protect seedlings, improves the photosynthetic activity of plants and at the same time acts as a stress factor that activates protecting enzymes (catalase, peroxidase), which trigger the development of protective adaptive reactions of plants.

Multiple functional motifs in the chicken U1 RNA gene enhancer

1987 ◽  
Vol 7 (12) ◽  
pp. 4185-4193
Author(s):  
K A Roebuck ◽  
R J Walker ◽  
W E Stumph
Keyword(s):  
Gene Expression ◽  
Dna Sequences ◽  
Initiation Site ◽  
Sequence Motifs ◽  
Small Nuclear Rna ◽  
Multiple Sequence ◽  
Transcriptional Initiation ◽  
Transcription System ◽  
Cell Extracts ◽  
Gene Enhancer

The DNA sequence requirements of chicken U1 RNA gene expression have been examined in an oocyte transcription system. An enhancer region, which was required for efficient U1 RNA gene expression, is contained within a region of conserved DNA sequences spanning nucleotide positions -230 to -183, upstream of the transcriptional initiation site. These DNA sequences can be divided into at least two distinct subregions or domains that acted synergistically to provide a greater than 20-fold stimulation of U1 RNA synthesis. The first domain contains the octamer sequence ATGCAAAT and was recognized by a DNA-binding factor present in HeLa cell extracts. The second domain (the SPH domain) consists of conserved sequences immediately downstream of the octamer and is an essential component of the enhancer. In the oocyte, the DNA sequences of the SPH domain were able to enhance gene expression at least 10-fold in the absence of the octamer domain. In contrast, the octamer domain, although required for full U1 RNA gene activity, was unable to stimulate expression in the absence of the adjacent downstream DNA sequences. These findings imply that sequences 3' of the octamer play a major role in the function of the chicken U1 RNA gene enhancer. This concept was supported by transcriptional competition studies in which a cloned chicken U4B RNA gene was used to compete for limiting transcription factors in oocytes. Multiple sequence motifs that can function in a variety of cis-linked configurations may be a general feature of vertebrate small nuclear RNA gene enhancers.

Evolutionary History of Plant Lipolytic Enzymes

2018 ◽  
pp. 155-178
Keyword(s):  
Higher Plants ◽  
Evolutionary Relationship ◽  
Biological Evolution ◽  
Sequence Motifs ◽  
Multiple Sequence ◽  
Lipolytic Enzymes ◽  
Conserved Sequence ◽  
Potential Applications ◽  
History Of ◽  
Living Organisms

The discovery of enzymes with lipolytic activities in all kingdoms of life from prokaryote to eukaryote species raises the possibility of the presence of an evolutionary relationship history of these proteins among many species of various living organisms. The chapter suggests a strategy based on the phylogenetic distribution and homology conservation in plant lipolytic enzymes for possible depiction of their biological evolution. Extensive databases and online resources for lipidomics and related areas are useful tools to analyze the different lipolytic enzymes in the three major super kingdoms of life, including higher plants kingdom and confined organisms such as algae that have recently gained much interest due to their promising potential applications in lipids hydrolysis and biosynthesis. Multiple sequence alignments of the identified lipolytic enzymes from databases could serve to the identification of globally conserved residues as well as conserved sequence motifs. Estimation of evolutionary distance between the various identified lipolytic enzymes could also be carried out to better understand the pattern of evolution.

scholarly journals Arabidopsis Nuclear-Encoded Plastid Transit Peptides Contain Multiple Sequence Subgroups with Distinctive Chloroplast-Targeting Sequence Motifs

2008 ◽  
Vol 20 (6) ◽  
pp. 1603-1622 ◽  
Author(s):  
Dong Wook Lee ◽  
Jong Kyoung Kim ◽  
Sumin Lee ◽  
Seungjin Choi ◽  
Sanguk Kim ◽  
...  
Keyword(s):  
Sequence Motifs ◽  
Multiple Sequence ◽  
Chloroplast Targeting ◽  
Transit Peptides

scholarly journals Evolutionary Relationships and Sequence-Structure Determinants in Human SARS Coronavirus-2 Spike Proteins for Host Receptor Recognition

2020 ◽  
Author(s):  
Lalitha Guruprasad
Keyword(s):  
Phylogenetic Trees ◽  
Disulfide Bridge ◽  
Sequence Motifs ◽  
Structural Determinants ◽  
Sequence Alignments ◽  
Multiple Sequence ◽  
Angiotensin Converting Enzyme 2 ◽  
Multiple Sequence Alignments ◽  
Loop 2 ◽  
Spike Proteins

<div>Coronavirus disease 2019 (COVID-19) is a pandemic infectious disease caused by novel Severe Acute Respiratory Syndrome coronavirus-2 (SARS CoV-2). The SARS CoV-2 is transmitted more rapidly and readily than SARS CoV. Both, SARS CoV and SARS CoV-2 via their glycosylated spike proteins recognize the human angiotensin converting enzyme-2 (ACE-2) receptor. We generated multiple sequence alignments and phylogenetic trees for representative spike proteins of CoV and CoV-2 from various host sources in order to analyze the specificity in SARS CoV-2 spike proteins required for causing infection in humans. Our results show that two sequence motifs in the N-terminal domain; "MESEFR" and "SYLTPG" are specific to human SARS CoV-2 and pangolin SARS CoV. In the receptor binding domain (RBD), three sequence loops; VGGNY (loop 1), YQAGSTPC (loop 2), EGFNCY (loop 3) and a tethered disulfide bridge Cys480-Cys488 connecting loops 2 and 3 are structural determinants for the recognition of human ACE-2 receptor. The complete genome analysis of representative SARS CoVs from bat, civet, pangolin, human host sources and human SARS CoV-2 identified the bat genome (GenBank code: MN996532.1) and the pangolin SARS CoV genomes as closest to the recent novel human SARS CoV-2 genomes. The bat CoV genomes (GenBank codes: MG772933 and MG772934) are evolutionary intermediates in the mutagenesis progression towards becoming human SARS CoV-2. </div>

Structures of K42N and K42Y sperm whale myoglobins point to an inhibitory role of distal water in peroxidase activity

2014 ◽  
Vol 70 (11) ◽  
pp. 2833-2839 ◽  
Author(s):  
Chunxue Wang ◽  
Leslie L. Lovelace ◽  
Shengfang Sun ◽  
John H. Dawson ◽  
Lukasz Lebioda
Keyword(s):  
Peroxidase Activity ◽  
Physiological Role ◽  
Sperm Whale ◽  
Reaction Rates ◽  
Heme Iron ◽  
Oxygen Storage ◽  
Dual Function ◽  
Amphitrite Ornata ◽  
Coordinated Water

Sperm whale myoglobin (Mb) functions as an oxygen-storage protein, but in the ferric state it possesses a weak peroxidase activity which enables it to carry out H2O2-dependent dehalogenation reactions. Hemoglobin/dehaloperoxidase fromAmphitrite ornata(DHP) is a dual-function protein represented by two isoproteins DHP A and DHP B; its peroxidase activity is at least ten times stronger than that of Mb and plays a physiological role. The `DHP A-like' K42Y Mb mutant (K42Y) and the `DHP B-like' K42N mutant (K42N) were engineered in sperm whale Mb to mimic the extended heme environments of DHP A and DHP B, respectively. The peroxidase reaction rates increased ∼3.5-fold and ∼5.5-fold in K42Y and K42NversusMb, respectively. The crystal structures of the K42Y and K42N mutants revealed that the substitutions at position 42 slightly elongate not only the distances between the distal His55 and the heme iron but also the hydrogen-bonding distances between His55 and the Fe-coordinated water. The enhanced peroxidase activity of K42Y and K42N thus might be attributed in part to the weaker binding of the axial water molecule that competes with hydrogen peroxide for the binding site at the heme in the ferric state. This is likely to be the mechanism by which the relationship `longer distal histidine to Fe distance – better peroxidase activity', which was previously proposed for heme proteins by Matsuiet al.(1999) (J. Biol. Chem.274, 2838–2844), works. Furthermore, positive cooperativity in K42N was observed when its dehaloperoxidase activity was measured as a function of the concentration of the substrate trichlorophenol. This serendipitously engineered cooperativity was rationalized by K42N dimerization through the formation of a dityrosine bond induced by excess H2O2.

scholarly journals U1 snRNP-Dependent Function of TIAR in the Regulation of Alternative RNA Processing of the Human Calcitonin/CGRP Pre-mRNA

2003 ◽  
Vol 23 (17) ◽  
pp. 5959-5971 ◽  
Author(s):  
Hui Zhu ◽  
Robert A. Hasman ◽  
Katherine M. Young ◽  
Nancy L. Kedersha ◽  
Hua Lou
Keyword(s):  
Splice Site ◽  
Rna Processing ◽  
Rna Binding ◽  
Sequence Motif ◽  
Human Calcitonin ◽  
Sequence Motifs ◽  
Multiple Sequence ◽  
Enhancer Element ◽  
Binding Domains ◽  
U6 Snrna

ABSTRACT Alternative RNA processing of human calcitonin/CGRP pre-mRNA is regulated by an intronic enhancer element. Previous studies have demonstrated that multiple sequence motifs within the enhancer and a number of trans-acting factors play critical roles in the regulation. Here, we report the identification of TIAR as a novel player in the regulation of human calcitonin/CGRP alternative RNA processing. TIAR binds to the U tract sequence motif downstream of a pseudo 5′ splice site within the previously characterized intron enhancer element. Binding of TIAR promotes inclusion of the alternative 3′-terminal exon located more than 200 nucleotides upstream from the U tract. In cells that preferentially include this exon, overexpression of a mutant TIAR that lacks the RNA binding domains suppressed inclusion of this exon. In this report, we also demonstrate an unusual novel interaction between U6 snRNA and the pseudo 5′ splice site, which was shown previously to bind U1 snRNA. Interestingly, TIAR binding to the U tract sequence depends on the interaction of not only U1 but also U6 snRNA with the pseudo 5′ splice site. Conversely, TIAR binding promotes U6 snRNA binding to its target. The synergistic relationship between TIAR and U6 snRNA strongly suggests a novel role of U6 snRNP in regulated alternative RNA processing.

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