scholarly journals Modification of N-Terminal α-Amine of Proteins via Biomimetic ortho-quinone-mediated Oxidation

2020 ◽  
Author(s):  
Ping Wang ◽  
Siyao Wang ◽  
Qingqing Zhou ◽  
Yunxue Li ◽  
Xiaoping Chen ◽  
...  
Keyword(s):  
Cell Viability ◽  
Protein Modification ◽  
Reduction Potential ◽  
Biological Processes ◽  
Complementary Approach ◽  
N Terminus ◽  
Anti Hiv ◽  
Mediated Oxidation

Abstract Naturally abundant quinones are important molecules, which play essential roles in various biological processes due to their reduction potential. In contrast to their universality, the reactions between quinones and proteins remain sparse. Herein, we report the development of unprecedented strategy to protein modification via a biomimetic quinone-mediated oxidation at the N-terminus. By exploiting unique reactivity of an ortho-quinone reagent, the α-amine of protein N-terminus was oxidized to generate aldo or keto handle for orthogonal conjugation. Its applications have been demonstrated using a range of proteins, including myoglobin and ubiquitin. The effect of this method was further highlighted via the preparation of a series of 17 MIP-1β analogs, followed by preliminary anti-HIV activity and cell viability assays, respectively. This method offers a fast, efficient and complementary approach to existing strategies for protein N-terminus modification.

scholarly journals Modification of N-terminal α-amine of proteins via biomimetic ortho-quinone-mediated oxidation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Siyao Wang ◽  
Qingqing Zhou ◽  
Xiaoping Chen ◽  
Rong-Hua Luo ◽  
Yunxue Li ◽  
...  
Keyword(s):  
Cell Viability ◽  
Protein Modification ◽  
Reduction Potential ◽  
Biological Processes ◽  
Inflammatory Protein ◽  
Complementary Approach ◽  
Anti Hiv ◽  
Macrophage Inflammatory Protein ◽  
Mediated Oxidation

AbstractNaturally abundant quinones are important molecules, which play essential roles in various biological processes due to their reduction potential. In contrast to their universality, the investigation of reactions between quinones and proteins remains sparse. Herein, we report the development of a convenient strategy to protein modification via a biomimetic quinone-mediated oxidation at the N-terminus. By exploiting unique reactivity of an ortho-quinone reagent, the α-amine of protein N-terminus is oxidized to generate aldo or keto handle for orthogonal conjugation. The applications have been demonstrated using a range of proteins, including myoglobin, ubiquitin and small ubiquitin-related modifier 2 (SUMO2). The effect of this method is further highlighted via the preparation of a series of 17 macrophage inflammatory protein 1β (MIP-1β) analogs, followed by preliminary anti-HIV activity and cell viability assays, respectively. This method offers an efficient and complementary approach to existing strategies for N-terminal modification of proteins.

scholarly journals Regulation of mRNA cap methylation

2009 ◽  
Vol 425 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Victoria H. Cowling
Keyword(s):  
Gene Expression ◽  
Cell Viability ◽  
Nuclear Export ◽  
Present Review ◽  
Biological Processes ◽  
Experimental Systems ◽  
Efficient Gene ◽  
Cellular Mrnas ◽  
Eukaryotic Organisms ◽  
The Impact

The 7-methylguanosine cap added to the 5′ end of mRNA is essential for efficient gene expression and cell viability. Methylation of the guanosine cap is necessary for the translation of most cellular mRNAs in all eukaryotic organisms in which it has been investigated. In some experimental systems, cap methylation has also been demonstrated to promote transcription, splicing, polyadenylation and nuclear export of mRNA. The present review discusses how the 7-methylguanosine cap is synthesized by cellular enzymes, the impact that the 7-methylguanosine cap has on biological processes, and how the mRNA cap methylation reaction is regulated.

scholarly journals Histone mimicry and hijacking of host proteins by influenza virus protein NS1

2014 ◽  
Vol 70 (a1) ◽  
pp. C1591-C1591
Author(s):  
Su Qin ◽  
Yanli Liu ◽  
Wolfram Tempel ◽  
Mohammad Eram ◽  
Chuanbing Bian ◽  
...  
Keyword(s):  
Influenza A ◽  
Associated Factors ◽  
Cellular Proteins ◽  
Carboxyl Terminus ◽  
Virus Protein ◽  
Biological Processes ◽  
Ns1 Protein ◽  
Host Proteins ◽  
N Terminus ◽  
Histone H3k4

Pathogens can interfere with vital biological processes of their host by mimicking host proteins. The NS1 protein of the influenza A H3N2 subtype possesses a histone H3K4-like sequence at its carboxyl terminus and has been reported to use this mimic to hijack host proteins. However, this mimic lacks a free N-terminus that is essential for binding to many known H3K4 readers. Here we show that the double chromodomains of CHD1adopt an 'open pocket' to interact with the free N-terminal amine of H3K4, and the open pocket permits the NS1 mimic to bind in a distinct conformation. We also explored the possibility that NS1 hijacks other cellular proteins and found that the NS1 mimic has access to only a subset of chromatin-associated factors, such as WDR5. Moreover, methylation of the NS1 mimic can not be reversed by the H3K4 demethylase LSD1. Overall, we thus conclude that the NS1 mimic is an imperfect histone mimic.

scholarly journals SUMO: From Bench to Bedside

2020 ◽  
Vol 100 (4) ◽  
pp. 1599-1619 ◽  
Author(s):  
Hui-Ming Chang ◽  
Edward T. H. Yeh
Keyword(s):  
Cellular Localization ◽  
Protein Modification ◽  
Redox Regulation ◽  
Biological Processes ◽  
Protein Activity ◽  
Protein Protein Interaction ◽  
The Family ◽  
Lysine Residues ◽  
Sumo Pathway ◽  
Posttranslational Protein Modification

Sentrin/small ubiquitin-like modifier (SUMO) is protein modification pathway that regulates multiple biological processes, including cell division, DNA replication/repair, signal transduction, and cellular metabolism. In this review, we will focus on recent advances in the mechanisms of disease pathogenesis, such as cancer, diabetes, seizure, and heart failure, which have been linked to the SUMO pathway. SUMO is conjugated to lysine residues in target proteins through an isopeptide linkage catalyzed by SUMO-specific activating (E1), conjugating (E2), and ligating (E3) enzymes. In steady state, the quantity of SUMO-modified substrates is usually a small fraction of unmodified substrates due to the deconjugation activity of the family Sentrin/SUMO-specific proteases (SENPs). In contrast to the complexity of the ubiquitination/deubiquitination machinery, the biochemistry of SUMOylation and de-SUMOylation is relatively modest. Specificity of the SUMO pathway is achieved through redox regulation, acetylation, phosphorylation, or other posttranslational protein modification of the SUMOylation and de-SUMOylation enzymes. There are three major SUMOs. SUMO-1 usually modifies a substrate as a monomer; however, SUMO-2/3 can form poly-SUMO chains. The monomeric SUMO-1 or poly-SUMO chains can interact with other proteins through SUMO-interactive motif (SIM). Thus SUMO modification provides a platform to enhance protein-protein interaction. The consequence of SUMOylation includes changes in cellular localization, protein activity, or protein stability. Furthermore, SUMO may join force with ubiquitin to degrade proteins through SUMO-targeted ubiquitin ligases (STUbL). After 20 yr of research, SUMO has been shown to play critical roles in most, if not all, biological pathways. Thus the SUMO enzymes could be targets for drug development to treat human diseases.

scholarly journals Dependence of ORC Silencing Function on NatA-Mediated Nα Acetylation in Saccharomyces cerevisiae

2004 ◽  
Vol 24 (23) ◽  
pp. 10300-10312 ◽  
Author(s):  
Antje Geissenhöner ◽  
Christoph Weise ◽  
Ann E. Ehrenhofer-Murray
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Modification ◽  
Origin Recognition Complex ◽  
Synthetic Lethality ◽  
Large Subunit ◽  
Functional Link ◽  
Repressive Chromatin ◽  
N Terminus ◽  
Synthetically Lethal

ABSTRACT Nα acetylation is one of the most abundant protein modifications in eukaryotes and is catalyzed by N-terminal acetyltransferases (NATs). NatA, the major NAT in Saccharomyces cerevisiae, consists of the subunits Nat1p, Ard1p, and Nat5p and is necessary for the assembly of repressive chromatin structures. Here, we found that Orc1p, the large subunit of the origin recognition complex (ORC), required NatA acetylation for its role in telomeric silencing. NatA functioned genetically through the ORC binding site of the HMR-E silencer. Furthermore, tethering Orc1p directly to the silencer circumvented the requirement for NatA in silencing. Orc1p was Nα acetylated in vivo by NatA. Mutations that abrogated its ability to be acetylated caused strong telomeric derepression. Thus, Nα acetylation of Orc1p represents a protein modification that modulates chromatin function in S. cerevisiae. Genetic evidence further supported a functional link between NatA and ORC: (i) nat1Δ was synthetically lethal with orc2-1 and (ii) the synthetic lethality between nat1Δ and SUM1-1 required the Orc1 N terminus. We also found Sir3p to be acetylated by NatA. In summary, we propose a model by which Nα acetylation is required for the binding of silencing factors to the N terminus of Orc1p and Sir3p to recruit heterochromatic factors and establish repression.

Recognition of hyperacetylated N-terminus of H2AZ by TbBDF2 from Trypanosoma brucei

2017 ◽  
Vol 474 (22) ◽  
pp. 3817-3830 ◽  
Author(s):  
Xiao Yang ◽  
Xuelei Wu ◽  
Jiahai Zhang ◽  
Xuecheng Zhang ◽  
Chao Xu ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Binding Sites ◽  
Gene Expression Regulation ◽  
Binding Pocket ◽  
Lysine Acetylation ◽  
Biological Processes ◽  
Left Handed ◽  
N Terminus ◽  
Small Molecule Compound ◽  
Loop Regions

Histone modification plays an important role in various biological processes, including gene expression regulation. Bromodomain, as one of histone readers, recognizes specifically the ε-N-lysine acetylation (KAc) of histone. Although the bromodomains and histone acetylation sites of Trypanosoma brucei (T. brucei), a lethal parasite responsible for sleeping sickness in human and nagana in cattle, have been identified, how acetylated histones are recognized by bromodomains is still unknown. Here, the bromodomain factor 2 (TbBDF2) from T. brucei was identified to be located in the nucleolus and bind to the hyperacetylated N-terminus of H2AZ which dimerizes with H2BV. The bromodomain of TbBDF2 (TbBDF2-BD) displays a conserved fold that comprises a left-handed bundle of four α-helices (αZ, αA, αB, αC), linked by loop regions of variable length (ZA and BC loops), which form the KAc-binding pocket. NMR chemical shift perturbation further revealed that TbBDF2-BD binds to the hyperacetylated N-terminus of H2AZ through its KAc-binding pocket. By structure-based virtual screening combining with the ITC experiment, a small molecule compound, GSK2801, was shown to have high affinity to TbBDF2-BD. GSK2801 and the hyperacetylated N-terminus of H2AZ have similar binding sites on TbBDF2-BD. In addition, GSK2801 competitively inhibits the hyperacetylated N-terminus of H2AZ binding to TbBDF2-BD. After treatment of GSK2801, cell growth was inhibited and localization of TbBDF2 was disrupted. Our results report a novel bromodomain-histone recognition by TbBDF2-BD and imply that TbBDF2 may serve as a potential chemotherapeutic target for the treatment of trypanosomiasis.

scholarly journals Fragile Gene WWOX Guides TFAP2A/TFAP2C-Dependent Actions Against Tumor Progression in Grade II Bladder Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Damian Kołat ◽  
Żaneta Kałuzińska ◽  
Elżbieta Płuciennik
Keyword(s):  
Bladder Cancer ◽  
Transcription Factors ◽  
Matrix Metalloproteinase ◽  
Tumor Cell ◽  
Cell Viability ◽  
Migration Rate ◽  
Matrix Metalloproteinase 2 ◽  
Biological Processes ◽  
Bladder Carcinogenesis ◽  
Grade Ii

IntroductionThe presence of common fragile sites is associated with no-accidental chromosomal instability which occurs prior to carcinogenesis. The WWOX gene spans the second most active fragile site: FRA16D. Chromosomal breakage at this site is more common in bladder cancer patients who are tobacco smokers which suggests the importance of WWOX gene loss regarding bladder carcinogenesis. Tryptophan domains of WWOX are known to recognize motifs of other proteins such as AP-2α and AP-2γ allowing protein-protein interactions. While the roles of both AP-2 transcription factors are important for bladder carcinogenesis, their nature is different. Based on the literature, AP-2γ appears to be oncogenic, whereas AP-2α mainly exhibits tumor suppressor character. Presumably, the interaction between WWOX and both transcription factors regulates thousands of genes, hence the aim of the present study was to determine WWOX, AP-2α, and AP-2γ function in modulating biological processes of bladder cancer.MethodsRT-112 cell line (grade II bladder cancer) was subjected to two stable lentiviral transductions. Overall, this resulted in six variants to investigate distinct WWOX, AP-2α, or AP-2γ function as well as WWOX in collaboration with a particular transcription factor. Cellular models were examined with immunocytochemical staining and in terms of differences in biological processes using assays investigating cell viability, proliferation, apoptosis, adhesion, clonogenicity, migration, activity of metalloproteinases and 3D culture growth.ResultsWWOX overexpression increased apoptosis but decreased cell viability, migration and large spatial colonies. AP-2α overexpression decreased tumor cell viability, migratory potential, matrix metalloproteinase-2 activity and clonogenicity. AP-2γ overexpression decreased matrix metalloproteinase-2 activity but increased wound healing, adhesion, clonogenicity and spatial colony formation. WWOX and AP-2α overexpression induced apoptosis but decreased cell viability, adhesion, matrix metalloproteinase-2 activity, overall number of cultured colonies and migration rate. WWOX and AP-2γ overexpression decreased tumor cell viability, proliferation potential, adhesion, clonogenicity and the ability to create spatial structures, but also increased apoptosis or migration rate.ConclusionCo-overexpression of WWOX with AP-2α or WWOX with AP-2γ resulted in a net anti-tumor effect. However, considering this research findings and the difference between AP-2α and AP-2γ, we suggest that this similarity is due to a divergent behavior of WWOX.

scholarly journals Histone deacetylase inhibition enhances the therapeutic effects of methotrexate on primary central nervous system lymphoma

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Kenji Fujimoto ◽  
Naoki Shinojima ◽  
Mitsuhiro Hayashi ◽  
Tomoyuki Nakano ◽  
Koichi Ichimura ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cell Viability ◽  
Tumor Cells ◽  
Histone Deacetylase ◽  
Protein Modification ◽  
Histone Deacetylase Inhibitors ◽  
Central Nervous System Lymphoma ◽  
Therapeutic Effects ◽  
Combined Effects

Abstract Background Polyglutamylation is a reversible protein modification that commonly occurs in tumor cells. Methotrexate (MTX) in tumor cells is polyglutamylated and strongly binds to dihydrofolate reductase (DHFR) without competitive inhibition by leucovorin. Therefore, tumor cells with high polyglutamylation levels are supposed to be selectively killed, whereas normal cells with lower polyglutamylation are rescued by leucovorin. This study investigated the combined effects of MTX plus histone deacetylase inhibitors (HDACIs), which upregulate MTX polyglutamylation, in primary central nervous system lymphoma (PCNSL). Methods We evaluated cell viability after MTX treatment and leucovorin rescue and compared the expression of folylpolyglutamate synthetase (FPGS), γ-glutamyl hydrolase (GGH), and DHFR in 2 human PCNSL-derived cell lines (HKBML and TK) and a human Burkitt lymphoma cell line (TL-1). Combination treatments were created using 4 HDACIs: panobinostat, vorinostat, sodium butyrate, and valproic acid. The expression of DHFR was examined as well as ratios of FPGS/GGH expression. The combined effects of MTX plus HDACIs were evaluated using a cell viability assay, mass spectroscopy imaging, and subcutaneous and intracranial xenograft models. Results HDACIs upregulated the ratio of FPGS/GGH expression resulting in increased polyglutamylation of MTX, but also downregulated expression of the target molecule of MTX: DHFR. The combination of MTX and vorinostat decreased cell viability in vitro (P < .05) and tumor volumes in a subcutaneous model (P < .0001), and prolonged survival in an intracranial model (P < .01), relative to controls. Conclusion HDACIs enhanced the therapeutic effect of MTX through increased polyglutamylation of MTX and concomitant downregulation of DHFR expression.

scholarly journals Research on Transboundary Regulation of Plant-Derived Exogenous MiRNA Based on Biological Big Data

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhi Li ◽  
Xu Wei ◽  
Shuyi Li ◽  
Jiashi Zhao ◽  
Xiang Li ◽  
...  
Keyword(s):  
Big Data ◽  
Human Body ◽  
Protein Modification ◽  
Eating Habits ◽  
Gene Prediction ◽  
Experimental Studies ◽  
Biological Processes ◽  
Plant Mirnas ◽  
Cross Border ◽  
Regulation Model

In recent years, researchers have discovered plant miRNA (plant xenomiR) in mammalian samples, but it is unclear whether it exists stably and participates in regulation. In this paper, a cross-border regulation model of plant miRNAs based on biological big data is constructed to study the possible cross-border regulation of plant miRNAs. Firstly, a variety of human edible plants were selected, and based on the miRNA data detected in human experimental studies, screening was performed to obtain the plant xenomiR that may stably exist in the human body. Then, we use plant and animal target gene prediction methods to obtain the mRNAs of animals and plants that may be regulated, respectively. Finally, we use GO (Gene Ontology) and the Multiple Dimensional Scaling (MDS) algorithm to analyze the biological processes regulated by plants and animals. We obtain the relationship between different biological processes and explore the regulatory commonality and individuality of plant xenomiR in plants and humans. Studies have shown that the development and metabolic functions of the human body are affected by daily eating habits. Soybeans, corn, and rice can not only affect the daily development and metabolism of the human body but also regulate biological processes such as protein modification and mitosis. This conclusion explains the reasons for the different physiological functions of the human body. This research is an important meaning for the design of small RNA drugs in Chinese herbal medicine and the treatment of human nutritional diseases.

scholarly journals Selective N-Terminal Cysteine Protein Modification with Cyclopropenones

2020 ◽  
Author(s):  
Alena Istrate ◽  
Claudio D. Navo ◽  
Bárbara B. Sousa ◽  
Marta C. Marques ◽  
Michael Deery ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Modification ◽  
Cysteine Residues ◽  
Biological Processes ◽  
Cysteine Modification ◽  
Specific Amino Acid ◽  
Protein Conjugates ◽  
Drug Conjugates ◽  
Ring Open ◽  
Antibody Drug

<div><div><div><p>Protein conjugates are valuable tools to create therapeutics, such as antibody-drug conjugates, or to study biological processes. Despite a number of protein conjugation strategies having been developed over recent years, the ability to modify one specific amino acid on a protein in the presence of other side chains with similar reactivity remains a challenge. We used the reaction between a monosubstituted cyclopropenone (CPO) probe and the 1,2-aminothiol of an N-terminal cysteine to give a stable 1,4-thiazepa-5-none linkage under mild, biocompatible conditions. The method relies on the ability of cyclopropenones to ring-open after sequential sulfhydryl and α-amine conjugation to be truly specific for N-terminal cysteine. We show that our CPO probes selectively label N-terminal cysteine containing peptides and proteins even in the presence of internal, solvent-exposed cysteines, which can be subsequently modified by using conventional cysteine modification reagents. The ability to distinguish and specifically target N-terminal cysteine residues on a protein will facilitate the construction of elaborate multi-labelled bioconjugates.</p></div></div></div>

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