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Sofeo N, Winkelman DC, Leung K, Nikolau BJ. Modulation of plant acetyl-CoA synthetase activity by post-translational lysine acetylation. Front Mol Biosci 2023; 10:1117921. [PMID: 37006614 PMCID: PMC10062202 DOI: 10.3389/fmolb.2023.1117921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/23/2023] [Indexed: 03/18/2023] Open
Abstract
Acetyl-CoA synthetase (ACS) is one of several enzymes that generate the key metabolic intermediate, acetyl-CoA. In microbes and mammals ACS activity is regulated by the post-translational acetylation of a key lysine residue. ACS in plant cells is part of a two-enzyme system that maintains acetate homeostasis, but its post-translational regulation is unknown. This study demonstrates that the plant ACS activity can be regulated by the acetylation of a specific lysine residue that is positioned in a homologous position as the microbial and mammalian ACS sequences that regulates ACS activity, occurring in the middle of a conserved motif, near the carboxyl-end of the protein. The inhibitory effect of the acetylation of residue Lys-622 of the Arabidopsis ACS was demonstrated by site-directed mutagenesis of this residue, including its genetic substitution with the non-canonical N-ε-acetyl-lysine residue. This latter modification lowered the catalytic efficiency of the enzyme by a factor of more than 500-fold. Michaelis-Menten kinetic analysis of the mutant enzyme indicates that this acetylation affects the first half-reaction of the ACS catalyzed reaction, namely, the formation of the acetyl adenylate enzyme intermediate. The post-translational acetylation of the plant ACS could affect acetate flux in the plastids and overall acetate homeostasis.
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Affiliation(s)
- Naazneen Sofeo
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
- Engineering Research Center for Biorenewable Chemicals Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
| | - Dirk C. Winkelman
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
| | - Karina Leung
- Engineering Research Center for Biorenewable Chemicals Iowa State University, Ames, IA, United States
| | - Basil J. Nikolau
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
- Engineering Research Center for Biorenewable Chemicals Iowa State University, Ames, IA, United States
- Center for Metabolic Biology, Iowa State University, Ames, IA, United States
- *Correspondence: Basil J. Nikolau,
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Araujo J, Ottinger S, Venkat S, Gan Q, Fan C. Studying Acetylation of Aconitase Isozymes by Genetic Code Expansion. Front Chem 2022; 10:862483. [PMID: 35402385 PMCID: PMC8987015 DOI: 10.3389/fchem.2022.862483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/08/2022] [Indexed: 11/24/2022] Open
Abstract
Aconitase catalyzes the second reaction of the tricarboxylic acid cycle, the reversible conversion of citrate and isocitrate. Escherichia coli has two isoforms of aconitase, AcnA and AcnB. Acetylomic studies have identified acetylation at multiple lysine sites of both E. coli aconitase isozymes, but the impacts of acetylation on aconitases are unknown. In this study, we applied the genetic code expansion approach to produce 14 site-specifically acetylated aconitase variants. Enzyme assays and kinetic analyses showed that acetylation of AcnA K684 decreased the enzyme activity, while acetylation of AcnB K567 increased the enzyme activity. Further in vitro acetylation and deacetylation assays were performed, which indicated that both aconitase isozymes could be acetylated by acetyl-phosphate chemically, and be deacetylated by the CobB deacetylase at most lysine sites. Through this study, we have demonstrated practical applications of genetic code expansion in acetylation studies.
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Affiliation(s)
- Jessica Araujo
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
| | - Sara Ottinger
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Sumana Venkat
- Children’s Research Institute, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Qinglei Gan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Chenguang Fan
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
- *Correspondence: Chenguang Fan,
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Chen H, Ercanbrack C, Wang T, Gan Q, Fan C. A Synthetic Reporter for Probing Mistranslation in Living Cells. Front Bioeng Biotechnol 2020; 8:623. [PMID: 32671035 PMCID: PMC7326783 DOI: 10.3389/fbioe.2020.00623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/21/2020] [Indexed: 01/13/2023] Open
Abstract
Aminoacyl-tRNA synthetases (AARSs) play key roles in maintaining high fidelity of protein synthesis. They charge cognate tRNAs with corresponding amino acids and hydrolyze mischarged tRNAs by editing mechanisms. Impairment of AARS editing activities can reduce the accuracy of tRNA aminoacylation to produce mischarged tRNAs, which cause mistranslation and cell damages. To evaluate the mistranslation rate of threonine codons in living cells, in this study, we designed a quantitative reporter derived from the green fluorescent protein (GFP). The original GFP has multiple threonine codons which could affect the accuracy of measurement, so we generated a GFP variant containing only one threonine residue to specifically quantify mistranslation at the threonine codon. To validate, we applied this single-threonine GFP reporter to evaluate mistranslation at the threonine codon with mutations or modifications of threonine-tRNA synthetase and compared it with other methods of mistranslation evaluation, which showed that this reporter is reliable and facile to use.
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Affiliation(s)
- Hao Chen
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
| | - Carson Ercanbrack
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Tony Wang
- Depratment of Biology, University of Arkansas, Fayetteville, AR, United States
| | - Qinglei Gan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
| | - Chenguang Fan
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States.,Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, United States
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Chen H, Venkat S, Hudson D, Wang T, Gan Q, Fan C. Site-Specifically Studying Lysine Acetylation of Aminoacyl-tRNA Synthetases. ACS Chem Biol 2019; 14:288-295. [PMID: 30642164 DOI: 10.1021/acschembio.8b01013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aminoacyl-tRNA synthetases (AARSs) charge their cognate tRNAs with corresponding amino acids, playing key roles in ribosomal protein synthesis. A series of proteomic studies have demonstrated that AARSs have levels of lysine acetylation much higher than those of other proteins in Escherichia coli. To study AARS acetylation, 25 site-specifically acetylated variants of four AARSs were generated by the genetic code expansion strategy. Kinetic analyses were performed to biochemically characterize the impact of site-specific acetylation on AARS functions, including amino acid activation, tRNA aminoacylation, and editing activities. The results showed that impacts of acetylation were different between class I and class II AARSs and also varied among the same class of AARSs. The results also showed that acetylation of threonyl-tRNA synthetase (ThrRS) could affect its editing function. Both in vivo and in vitro studies were further performed to explore the acetylation and deacetylation processes of ThrRS. Although nonenzymatic acetylation and CobB-dependent deacetylation were concluded, the results also indicated the existence of additional modifying enzymes or mechanisms for ThrRS acetylation and deacetylation.
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Chen H, Venkat S, McGuire P, Gan Q, Fan C. Recent Development of Genetic Code Expansion for Posttranslational Modification Studies. Molecules 2018; 23:E1662. [PMID: 29986538 PMCID: PMC6100177 DOI: 10.3390/molecules23071662] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 12/29/2022] Open
Abstract
Nowadays advanced mass spectrometry techniques make the identification of protein posttranslational modifications (PTMs) much easier than ever before. A series of proteomic studies have demonstrated that large numbers of proteins in cells are modified by phosphorylation, acetylation and many other types of PTMs. However, only limited studies have been performed to validate or characterize those identified modification targets, mostly because PTMs are very dynamic, undergoing large changes in different growth stages or conditions. To overcome this issue, the genetic code expansion strategy has been introduced into PTM studies to genetically incorporate modified amino acids directly into desired positions of target proteins. Without using modifying enzymes, the genetic code expansion strategy could generate homogeneously modified proteins, thus providing powerful tools for PTM studies. In this review, we summarized recent development of genetic code expansion in PTM studies for research groups in this field.
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Affiliation(s)
- Hao Chen
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA.
| | - Sumana Venkat
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA.
| | - Paige McGuire
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA.
| | - Qinglei Gan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
| | - Chenguang Fan
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA.
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
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Venkat S, Chen H, Stahman A, Hudson D, McGuire P, Gan Q, Fan C. Characterizing Lysine Acetylation of Isocitrate Dehydrogenase in Escherichia coli. J Mol Biol 2018; 430:1901-1911. [PMID: 29733852 PMCID: PMC5988991 DOI: 10.1016/j.jmb.2018.04.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 04/18/2018] [Accepted: 04/24/2018] [Indexed: 12/21/2022]
Abstract
The Escherichia coli isocitrate dehydrogenase (ICDH) is one of the tricarboxylic acid cycle enzymes, playing key roles in energy production and carbon flux regulation. E. coli ICDH was the first bacterial enzyme shown to be regulated by reversible phosphorylation. However, the effect of lysine acetylation on E. coli ICDH, which has no sequence similarity with its counterparts in eukaryotes, is still unclear. Based on previous studies of E. coli acetylome and ICDH crystal structures, eight lysine residues were selected for mutational and kinetic analyses. They were replaced with acetyllysine by the genetic code expansion strategy or substituted with glutamine as a classic approach. Although acetylation decreased the overall ICDH activity, its effects were different site by site. Deacetylation tests demonstrated that the CobB deacetylase could deacetylate ICDH both in vivo and in vitro, but CobB was only specific for lysine residues at the protein surface. On the other hand, ICDH could be acetylated by acetyl-phosphate chemically in vitro. And in vivo acetylation tests indicated that the acetylation level of ICDH was correlated with the amounts of intracellular acetyl-phosphate. This study nicely complements previous proteomic studies to provide direct biochemical evidence for ICDH acetylation.
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Affiliation(s)
- Sumana Venkat
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States; Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, United States
| | - Hao Chen
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States; Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, United States
| | - Alleigh Stahman
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
| | - Denver Hudson
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
| | - Paige McGuire
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, United States
| | - Qinglei Gan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
| | - Chenguang Fan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States; Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, United States.
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Venkat S, Sturges J, Stahman A, Gregory C, Gan Q, Fan C. Genetically Incorporating Two Distinct Post-translational Modifications into One Protein Simultaneously. ACS Synth Biol 2018; 7:689-695. [PMID: 29301074 DOI: 10.1021/acssynbio.7b00408] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Post-translational modifications (PTMs) play important roles in regulating a variety of biological processes. To facilitate PTM studies, the genetic code expansion strategy has been utilized to cotranslationally incorporate individual PTMs such as acetylation and phosphorylation into proteins at specific sites. However, recent studies have demonstrated that PTMs actually work together to regulate protein functions and structures. Thus, simultaneous incorporation of multiple distinct PTMs into one protein is highly desirable. In this study, we utilized the genetic incorporation systems of phosphoserine and acetyllysine to install both phosphorylation and acetylation into target proteins simultaneously in Escherichia coli. And we used this system to study the effect of coexisting acetylation and phosphorylation on malate dehydrogenase, demonstrating a practical application of this system in biochemical studies. Furthermore, we tested the mutual orthogonality of three widely used genetic incorporation systems, indicating the possibility of incorporating three distinct PTMs into one protein simultaneously.
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Affiliation(s)
- Sumana Venkat
- Department
of Chemistry and Biochemistry, ‡Cell and Molecular Biology Program, and §Department of
Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Jourdan Sturges
- Department
of Chemistry and Biochemistry, ‡Cell and Molecular Biology Program, and §Department of
Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Alleigh Stahman
- Department
of Chemistry and Biochemistry, ‡Cell and Molecular Biology Program, and §Department of
Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Caroline Gregory
- Department
of Chemistry and Biochemistry, ‡Cell and Molecular Biology Program, and §Department of
Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Qinglei Gan
- Department
of Chemistry and Biochemistry, ‡Cell and Molecular Biology Program, and §Department of
Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Chenguang Fan
- Department
of Chemistry and Biochemistry, ‡Cell and Molecular Biology Program, and §Department of
Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, United States
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