scholarly journals Characterization of Lysine Acetyltransferase Activity of Recombinant Human ARD1/NAA10

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 588 ◽  
Author(s):  
Tam Thuy Lu Vo ◽  
Ji-Hyeon Park ◽  
Eun Ji Lee ◽  
Yen Thi Kim Nguyen ◽  
Byung Woo Han ◽  
...  
Keyword(s):  
Size Exclusion ◽  
Lysine Acetylation ◽  
Monomeric Form ◽  
Experimental Conditions ◽  
Lysine Residues ◽  
Lysine Acetyltransferase ◽  
Over Time

Arrest defective 1 (ARD1), also known as N(alpha)-acetyltransferase 10 (NAA10) was originally identified as an N-terminal acetyltransferase (NAT) that catalyzes the acetylation of N-termini of newly synthesized peptides. After that, mammalian ARD1/NAA10 expanded its’ role to lysine acetyltransferase (KAT) that post-translationally acetylates internal lysine residues of proteins. ARD1/NAA10 is the only enzyme with both NAT and KAT activities. However, recent studies on the role of human ARD1/NAA10 (hARD1/NAA10) in lysine acetylation are contradictory, as crystal structure and in vitro acetylation assay results revealed the lack of KAT activity. Thus, the role of hARD1/NAA10 in lysine acetylation is still debating. Here, we found a clue that possibly explains these complicated and controversial results on KAT activity of hARD1/NAA10. Recombinant hARD1/NAA10 exhibited KAT activity, which disappeared soon in vitro. Size-exclusion analysis revealed that most recombinant hARD1/NAA10 formed oligomers over time, resulting in the loss of KAT activity. While oligomeric recombinant hARD1/NAA10 lost its ability for lysine acetylation, its monomeric form clearly exhibited lysine acetylation activity in vitro. We also characterized the KAT activity of hARD1/NAA10 that was influenced by several experimental conditions, including concentration of reactants and reaction time. Taken together, our study proves that recombinant hARD1/NAA10 exhibits KAT activity in vitro but only under accurate conditions, including reactant concentrations and reaction duration.

scholarly journals Effect of lysine acetylation on the regulation of Trypanosoma brucei glycosomal aldolase activity

2020 ◽  
Vol 477 (9) ◽  
pp. 1733-1744 ◽  
Author(s):  
Ariely Barbosa Leite ◽  
Antoniel Augusto Severo Gomes ◽  
Ana Caroline de Castro Nascimento Sousa ◽  
Marcos Roberto de Mattos Fontes ◽  
Sergio Schenkman ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Environmental Changes ◽  
In Silico Analysis ◽  
Lysine Acetylation ◽  
Lysine Residues ◽  
Acetyl Group ◽  
Aldolase Activity ◽  
Fructose 1,6 Bisphosphate

Post-translational modifications provide suitable mechanisms for cellular adaptation to environmental changes. Lysine acetylation is one of these modifications and occurs with the addition of an acetyl group to Nε-amino chain of this residue, eliminating its positive charge. Recently, we found distinct acetylation profiles of procyclic and bloodstream forms of Trypanosoma brucei, the agent of African Trypanosomiasis. Interestingly, glycolytic enzymes were more acetylated in the procyclic, which develops in insects and uses oxidative phosphorylation to obtain energy, compared with the bloodstream form, whose main source of energy is glycolysis. Here, we investigated whether acetylation regulates the T. brucei fructose 1,6-bisphosphate aldolase. We found that aldolase activity was reduced in procyclic parasites cultivated in the absence of glucose and partial recovered by in vitro deacetylation. Similarly, acetylation of protein extracts from procyclics cultivated in glucose-rich medium, caused a reduction in the aldolase activity. In addition, aldolase acetylation levels were higher in procyclics cultivated in the absence of glucose compared with those cultivated in the presence of glucose. To further confirm the role of acetylation, lysine residues near the catalytic site were substituted by glutamine in recombinant T. brucei aldolase. These replacements, especially K157, inhibited enzymatic activity, changed the electrostatic surface potential, decrease substrate binding and modify the catalytic pocket structure of the enzyme, as predicted by in silico analysis. Taken together, these data confirm the role of acetylation in regulating the activity of an enzyme from the glycolytic pathway of T. brucei, expanding the factors responsible for regulating important pathways in this parasite.

scholarly journals YfmK is an Nε-lysine acetyltransferase that directly acetylates the histone-like protein HBsu in Bacillus subtilis

2019 ◽  
Vol 116 (9) ◽  
pp. 3752-3757 ◽  
Author(s):  
Valerie J. Carabetta ◽  
Todd M. Greco ◽  
Ileana M. Cristea ◽  
David Dubnau
Keyword(s):  
Bacillus Subtilis ◽  
Biological Significance ◽  
Lysine Residues ◽  
Lysine Acetyltransferase ◽  
Sites Of Action ◽  
Protein Acetyltransferase ◽  
Encoding Genes

Nε-lysine acetylation is an abundant and dynamic regulatory posttranslational modification that remains poorly characterized in bacteria. In bacteria, hundreds of proteins are known to be acetylated, but the biological significance of the majority of these events remains unclear. Previously, we characterized the Bacillus subtilis acetylome and found that the essential histone-like protein HBsu contains seven previously unknown acetylation sites in vivo. Here, we investigate whether acetylation is a regulatory component of the function of HBsu in nucleoid compaction. Using mutations that mimic the acetylated and unacetylated forms of the protein, we show that the inability to acetylate key HBsu lysine residues results in a more compacted nucleoid. We further investigated the mechanism of HBsu acetylation. We screened deletions of the ∼50 putative GNAT domain-encoding genes in B. subtilis for their effects on DNA compaction, and identified five candidates that may encode acetyltransferases acting on HBsu. Genetic bypass experiments demonstrated that two of these, YfmK and YdgE, can acetylate Hbsu, and their potential sites of action on HBsu were identified. Additionally, purified YfmK was able to directly acetylate HBsu in vitro, suggesting that it is the second identified protein acetyltransferase in B. subtilis. We propose that at least one physiological function of the acetylation of HBsu at key lysine residues is to regulate nucleoid compaction, analogous to the role of histone acetylation in eukaryotes.

Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

2021 ◽  
pp. 1-9
Author(s):  
Etsuo Niki
Keyword(s):  
Biological Molecules ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Beneficial Effects ◽  
Multiple Oxidants ◽  
Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

scholarly journals Characterization of a Dye-Decolorizing Peroxidase from Irpex lacteus Expressed in Escherichia coli: An Enzyme with Wide Substrate Specificity Able to Transform Lignosulfonates

2021 ◽  
Vol 7 (5) ◽  
pp. 325
Author(s):  
Laura Isabel de de Eugenio ◽  
Rosa Peces-Pérez ◽  
Dolores Linde ◽  
Alicia Prieto ◽  
Jorge Barriuso ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Inclusion Bodies ◽  
Veratryl Alcohol ◽  
Dye Decolorization ◽  
Irpex Lacteus ◽  
Type D ◽  
Lignin Peroxidases

A dye-decolorizing peroxidase (DyP) from Irpex lacteus was cloned and heterologously expressed as inclusion bodies in Escherichia coli. The protein was purified in one chromatographic step after its in vitro activation. It was active on ABTS, 2,6-dimethoxyphenol (DMP), and anthraquinoid and azo dyes as reported for other fungal DyPs, but it was also able to oxidize Mn2+ (as manganese peroxidases and versatile peroxidases) and veratryl alcohol (VA) (as lignin peroxidases and versatile peroxidases). This corroborated that I. lacteus DyPs are the only enzymes able to oxidize high redox potential dyes, VA and Mn+2. Phylogenetic analysis grouped this enzyme with other type D-DyPs from basidiomycetes. In addition to its interest for dye decolorization, the results of the transformation of softwood and hardwood lignosulfonates suggest a putative biological role of this enzyme in the degradation of phenolic lignin.

scholarly journals An acute bleomycin inflammatory and fibrotic mouse model of morphea is dependent upon CXCL9 and CXCR3

2019 ◽  
Author(s):  
Jillian M. Richmond ◽  
Dhrumil Patel ◽  
Tomoya Watanabe ◽  
Colton J. Garelli ◽  
Madhuri Garg ◽  
...  
Keyword(s):  
Mouse Model ◽  
Localized Scleroderma ◽  
Lesional Skin ◽  
Chemokine Expression ◽  
Inflammatory Phase ◽  
Deficient Mice ◽  
Over Time ◽  
Cutaneous Fibrosis

AbstractMorphea, or localized scleroderma, is characterized by an inflammatory phase followed by cutaneous fibrosis, which may lead to disfigurement and/or disability. Previous work from our group showed that the CXCR3 ligands CXCL9 and CXCL10 are highly upregulated in lesional skin of morphea patients. Here, we used an acute inflammatory and fibrotic bleomycin mouse model of morphea to examine the role of the CXCR3 chemokine axis in pathogenesis. We first characterized which cells produce the CXCR3 ligands in the skin using the Reporter of Expression of CXCR3 ligands mouse (REX3). We found that fibroblasts contribute the bulk of CXCL9 and CXCL10, whereas endothelial cells are key dual chemokine producers. Macrophages, which have high MFI of chemokine expression, upregulated CXCL9 production over time, fibroblasts CXCL10 production, and T cells dual chemokine expression. To determine whether bleomycin treatment could directly induce expression of these chemokines, we treated cultured REX3 mouse dermis monolayers in vitro with bleomycin or IFNγ with TNF and found that bleomycin could induce low amounts of CXCL9 directly in fibroblasts, whereas the cytokines were required for optimal CXCL9 and CXCL10 production. To determine whether these chemokines are mechanistically involved in pathogenesis, we induced fibrosis in CXCL9, CXCL10, or CXCR3 deficient mice and found that fibrosis is dependent on CXCL9 and CXCR3. Addition of recombinant CXCL9, but not CXCL10, to cultured mouse fibroblasts induces collagen 1a1 mRNA expression, indicating the chemokine itself can contribute to fibrosis. Taken together, our studies provide evidence that acute intradermal bleomycin administration in mice can model inflammatory morphea, and that CXCL9 and its receptor CXCR3 are mechanistically involved in pathogenesis.One Sentence SummaryCXCL9 drives acute morphea pathogenesis in mice.

Effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator T4 DNA polymerase mutant

1984 ◽  
Vol 26 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Linda J. Reha-Krantz ◽  
Sükran Parmaksizoglu
Keyword(s):  
Dna Polymerase ◽  
Low Temperatures ◽  
Bacteriophage T4 ◽  
Effect Of Temperature ◽  
In Vitro Mutagenesis ◽  
Wild Type ◽  
Mutational Site

The effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage T4. The mutational site was a T4 rII ochre mutant which could revert to rII+ via a transversion or to the amber convertant via a transition. Temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator DNA polymerase mutant. Possible models to explain the role of temperature in mutagenesis are discussed as well as the significance of low temperatures for in vitro mutagenesis reactions.Key words: bacteriophage T4, mutator, transition, transversion, temperature effects.

scholarly journals The role of individual lysine residues in the basic patch on turnip cytochrome f for electrostatic interactions with plastocyanin in vitro

2000 ◽  
Vol 267 (12) ◽  
pp. 3461-3468 ◽  
Author(s):  
Xiao-Song Gong ◽  
Jiang Qi Wen ◽  
Nicholas E. Fisher ◽  
Simon Young ◽  
Christopher J. Howe ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Cytochrome F ◽  
Lysine Residues

Role of nutrient HCO3(-) in protection of amphibian gastric mucosa

1980 ◽  
Vol 239 (6) ◽  
pp. G536-G542
Author(s):  
R. Schiessel ◽  
A. Merhav ◽  
J. B. Matthews ◽  
L. A. Fleischer ◽  
A. Barzilai ◽  
...  
Keyword(s):  
Gastric Mucosa ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Experimental Conditions ◽  
Slow Decline ◽  
Alkaline Tide ◽  
Artificial Gastric Juice ◽  
Rapid Drop

In in vitro bullfrog fundic mucosa inhibited with 10(-3) M metiamide and exposed to a luminal pH of 2 a progressive slow decline in potential difference (PD) and short-circuit current (Isc) and a rise in resistance (R) were observed when the nutrient solution (N) contained 18 mM HCO3(-), but these changes were restored by an N containing 50 mM HCO3(-). Substitution of PO4(3-) or N-tris(hydroxymethyl)-methyl-2-aminoethanesulfonic acid for NHO3(-) in N caused a rapid drop in PD and Isc in inhibited tissues, changes that could be prevented by 10(-4) M histamine. Ulceration occurred more frequently in metiamide-inhibited gastric sacs exposed to artificial gastric juice with an N of 18 mMHCO3(-) than with 50 mM HCO3(-), but histamine prevented ulceration in the 18 mM HCO3(-) solution. JnetCl approximated Isc under most experimental conditions in inhibited mucosa and was reduced dramatically as were both Jn leads to sCl and Js leads to nCl when HCO3(-) was removed from N. In histamine-stimulated tissues, removal of nutrient HCO3(-) did not influence Cl- transport. Our results are consistent with the proposal that HCO3(-) in N supports normal Cl- flux and that the alkaline tide of actively secreting oxyntic cells can do the same in the absence of ambient HCO3(-).

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