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Qin C, Graf LG, Striska K, Janetzky M, Geist N, Specht R, Schulze S, Palm GJ, Girbardt B, Dörre B, Berndt L, Kemnitz S, Doerr M, Bornscheuer UT, Delcea M, Lammers M. Acetyl-CoA synthetase activity is enzymatically regulated by lysine acetylation using acetyl-CoA or acetyl-phosphate as donor molecule. Nat Commun 2024; 15:6002. [PMID: 39019872 PMCID: PMC11255334 DOI: 10.1038/s41467-024-49952-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 06/24/2024] [Indexed: 07/19/2024] Open
Abstract
The AMP-forming acetyl-CoA synthetase is regulated by lysine acetylation both in bacteria and eukaryotes. However, the underlying mechanism is poorly understood. The Bacillus subtilis acetyltransferase AcuA and the AMP-forming acetyl-CoA synthetase AcsA form an AcuA•AcsA complex, dissociating upon lysine acetylation of AcsA by AcuA. Crystal structures of AcsA from Chloroflexota bacterium in the apo form and in complex with acetyl-adenosine-5'-monophosphate (acetyl-AMP) support the flexible C-terminal domain adopting different conformations. AlphaFold2 predictions suggest binding of AcuA stabilizes AcsA in an undescribed conformation. We show the AcuA•AcsA complex dissociates upon acetyl-coenzyme A (acetyl-CoA) dependent acetylation of AcsA by AcuA. We discover an intrinsic phosphotransacetylase activity enabling AcuA•AcsA generating acetyl-CoA from acetyl-phosphate (AcP) and coenzyme A (CoA) used by AcuA to acetylate and inactivate AcsA. Here, we provide mechanistic insights into the regulation of AMP-forming acetyl-CoA synthetases by lysine acetylation and discover an intrinsic phosphotransacetylase allowing modulation of its activity based on AcP and CoA levels.
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Affiliation(s)
- Chuan Qin
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Leonie G Graf
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Kilian Striska
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Markus Janetzky
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Norman Geist
- Department of Biophysical Chemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Robin Specht
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Sabrina Schulze
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Gottfried J Palm
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Britta Girbardt
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Babett Dörre
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Leona Berndt
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Stefan Kemnitz
- Department for High Performance Computing, University Computing Center, University of Greifswald, 17489, Greifswald, Germany
| | - Mark Doerr
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Uwe T Bornscheuer
- Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Mihaela Delcea
- Department of Biophysical Chemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany
| | - Michael Lammers
- Department of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, 17489, Greifswald, Germany.
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Rizo J, Encarnación-Guevara S. Bacterial protein acetylation: mechanisms, functions, and methods for study. Front Cell Infect Microbiol 2024; 14:1408947. [PMID: 39027134 PMCID: PMC11254643 DOI: 10.3389/fcimb.2024.1408947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/03/2024] [Indexed: 07/20/2024] Open
Abstract
Lysine acetylation is an evolutionarily conserved protein modification that changes protein functions and plays an essential role in many cellular processes, such as central metabolism, transcriptional regulation, chemotaxis, and pathogen virulence. It can alter DNA binding, enzymatic activity, protein-protein interactions, protein stability, or protein localization. In prokaryotes, lysine acetylation occurs non-enzymatically and by the action of lysine acetyltransferases (KAT). In enzymatic acetylation, KAT transfers the acetyl group from acetyl-CoA (AcCoA) to the lysine side chain. In contrast, acetyl phosphate (AcP) is the acetyl donor of chemical acetylation. Regardless of the acetylation type, the removal of acetyl groups from acetyl lysines occurs only enzymatically by lysine deacetylases (KDAC). KATs are grouped into three main superfamilies based on their catalytic domain sequences and biochemical characteristics of catalysis. Specifically, members of the GNAT are found in eukaryotes and prokaryotes and have a core structural domain architecture. These enzymes can acetylate small molecules, metabolites, peptides, and proteins. This review presents current knowledge of acetylation mechanisms and functional implications in bacterial metabolism, pathogenicity, stress response, translation, and the emerging topic of protein acetylation in the gut microbiome. Additionally, the methods used to elucidate the biological significance of acetylation in bacteria, such as relative quantification and stoichiometry quantification, and the genetic code expansion tool (CGE), are reviewed.
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Affiliation(s)
| | - Sergio Encarnación-Guevara
- Laboratorio de Proteómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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Zhou Y, Zhang X, Yu W, Fu Y, Ni L, Yu J, Wang X, Song W, Wang C. Enhancing Pseudomonas cell growth for the production of medium-chain-length polyhydroxyalkanoates from Antarctic krill shell waste. Int J Biol Macromol 2024:133364. [PMID: 38917919 DOI: 10.1016/j.ijbiomac.2024.133364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 05/10/2024] [Accepted: 06/21/2024] [Indexed: 06/27/2024]
Abstract
Antarctic krill shell waste (AKSW), a byproduct of Antarctic krill processing, has substantial quantity but low utilization. Utilizing microbial-based cell factories, with Pseudomonas putida as a promising candidate, offers an ecofriendly and sustainable approach to producing valuable bioproducts from renewable sources. However, the high fluoride content in AKSW impedes the cell growth of P. putida. This study aims to investigate the transcriptional response of P. putida to fluoride stress from AKSW and subsequently conduct genetic modification of the strain based on insights gained from transcriptomic analysis. Notably, the engineered strain KT+16840+03100 exhibited a remarkable 33.7-fold increase in cell growth, capable of fermenting AKSW for medium-chain-length-polyhydroxyalkanoates (mcl-PHA) biosynthesis, achieving a 40.3-fold increase in mcl-PHA yield compared to the control strain. This research advances our understanding of how P. putida responds to fluoride stress from AKSW and provides engineered strains that serve as excellent platforms for producing mcl-PHA through AKSW.
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Affiliation(s)
- Yueyue Zhou
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China; Key Laboratory of Green Mariculture (Co-construction by Ministry and Province), Ministry of Agriculture and Rural, Ningbo 315000, China; Collaborative Innovation Center for Zhejiang Marine High-Efficiency and Healthy Aquaculture, Ningbo 315000, China.
| | - Xingyu Zhang
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China; Key Laboratory of Green Mariculture (Co-construction by Ministry and Province), Ministry of Agriculture and Rural, Ningbo 315000, China; Collaborative Innovation Center for Zhejiang Marine High-Efficiency and Healthy Aquaculture, Ningbo 315000, China
| | - Wenying Yu
- Ningbo Institute of Oceanography, Ningbo, Zhejiang, China
| | - Yuanyuan Fu
- Ningbo Institute of Oceanography, Ningbo, Zhejiang, China
| | - Lijuan Ni
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China
| | - Jiayi Yu
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China
| | - Xiaopeng Wang
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China; Key Laboratory of Green Mariculture (Co-construction by Ministry and Province), Ministry of Agriculture and Rural, Ningbo 315000, China; Collaborative Innovation Center for Zhejiang Marine High-Efficiency and Healthy Aquaculture, Ningbo 315000, China.
| | - Weiwei Song
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China; Key Laboratory of Green Mariculture (Co-construction by Ministry and Province), Ministry of Agriculture and Rural, Ningbo 315000, China; Collaborative Innovation Center for Zhejiang Marine High-Efficiency and Healthy Aquaculture, Ningbo 315000, China.
| | - Chunlin Wang
- Marine Economic Research Center, Donghai Academy, Ningbo University, Ningbo 315000, China; Key Laboratory of Green Mariculture (Co-construction by Ministry and Province), Ministry of Agriculture and Rural, Ningbo 315000, China; Collaborative Innovation Center for Zhejiang Marine High-Efficiency and Healthy Aquaculture, Ningbo 315000, China.
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Zhou M, Gamage ST, Tran KA, Bartee D, Wei X, Yin B, Berger S, Meier JL, Marmorstein R. Molecular Basis for RNA Cytidine Acetylation by NAT10. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.587050. [PMID: 38585770 PMCID: PMC10996708 DOI: 10.1101/2024.03.27.587050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Human NAT10 acetylates the N4 position of cytidine in RNA, predominantly on rRNA and tRNA, to facilitate ribosome biogenesis and protein translation. NAT10 has been proposed as a therapeutic target in cancers as well as aging-associated pathologies such as Hutchinson-Gilford Progeria Syndrome (HGPS). The ∼120 kDa NAT10 protein uses its acetyl-CoA-dependent acetyltransferase, ATP-dependent helicase, and RNA binding domains in concert to mediate RNA-specific N4-cytidine acetylation. While the biochemical activity of NAT10 is well known, the molecular basis for catalysis of eukaryotic RNA acetylation remains relatively undefined. To provide molecular insights into the RNA-specific acetylation by NAT10, we determined the single particle cryo-EM structures of Chaetomium thermophilum NAT10 ( Ct NAT10) bound to a bisubstrate cytidine-CoA probe with and without ADP. The structures reveal that NAT10 forms a symmetrical heart-shaped dimer with conserved functional domains surrounding the acetyltransferase active sites harboring the cytidine-CoA probe. Structure-based mutagenesis with analysis of mutants in vitro supports the catalytic role of two conserved active site residues (His548 and Tyr549 in Ct NAT10), and two basic patches, both proximal and distal to the active site for RNA-specific acetylation. Yeast complementation analyses and senescence assays in human cells also implicates NAT10 catalytic activity in yeast thermoadaptation and cellular senescence. Comparison of the NAT10 structure to protein lysine and N-terminal acetyltransferase enzymes reveals an unusually open active site suggesting that these enzymes have been evolutionarily tailored for RNA recognition and cytidine-specific acetylation.
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Zhang L, Tang Y, Merkler DJ, Han Q. Function, structure, evolution, regulation of a potent drug target, arylalkylamine N-acetyltransferase. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 134:211-223. [PMID: 36858736 DOI: 10.1016/bs.apcsb.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Arylalkylamine N-acetyltransferase (aaNAT) catalyzes the transacetylation of acetyl coenzyme A to arylamines and arylalkylamines. Based on three-dimensional structural information, aaNAT belongs to the GCN5-related N-acetyltransferases superfamily with a conserved acetyl-CoA binding domain (Dyda et al., 2000). By comparison of sequence similarity, aaNAT is usually divided into vertebrate aaNAT (VT-aaNAT) and non-vertebrate aaNAT (NV-aaNAT) (Cazaméa-Catalan et al., 2014). Insects have evolved multiple aaNATs in comparison to mammals, thus more diverse functions are also reflected in insects. This chapter will summarize previous studies on the function, regulation, structure and evolution of aaNAT, and provide insight into future pest management.
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Affiliation(s)
- Lei Zhang
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan, P.R. China; One Health Institute, Hainan University, Haikou, Hainan, P.R. China
| | - Yu Tang
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan, P.R. China; One Health Institute, Hainan University, Haikou, Hainan, P.R. China
| | - David J Merkler
- Department of Chemistry, University of South Florida, Tampa, FL, United States
| | - Qian Han
- Laboratory of Tropical Veterinary Medicine and Vector Biology, School of Life Sciences, Hainan University, Haikou, Hainan, P.R. China; One Health Institute, Hainan University, Haikou, Hainan, P.R. China.
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Post-Translational Modifications by Lipid Metabolites during the DNA Damage Response and Their Role in Cancer. Biomolecules 2022; 12:biom12111655. [DOI: 10.3390/biom12111655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/25/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Genomic DNA damage occurs as an inevitable consequence of exposure to harmful exogenous and endogenous agents. Therefore, the effective sensing and repair of DNA damage are essential for maintaining genomic stability and cellular homeostasis. Inappropriate responses to DNA damage can lead to genomic instability and, ultimately, cancer. Protein post-translational modifications (PTMs) are a key regulator of the DNA damage response (DDR), and recent progress in mass spectrometry analysis methods has revealed that a wide range of metabolites can serve as donors for PTMs. In this review, we will summarize how the DDR is regulated by lipid metabolite-associated PTMs, including acetylation, S-succinylation, N-myristoylation, palmitoylation, and crotonylation, and the implications for tumorigenesis. We will also discuss potential novel targets for anti-cancer drug development.
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7
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Crystal structure of the phage-encoded N-acetyltransferase in complex with acetyl-CoA, revealing a novel dimeric arrangement. J Microbiol 2022; 60:746-755. [DOI: 10.1007/s12275-022-2030-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/29/2022] [Accepted: 05/31/2022] [Indexed: 10/17/2022]
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Lyu J, Ushimaru R, Abe I. Characterization of Enzymes Catalyzing the Initial Steps of the β-Lactam Tabtoxin Biosynthesis. Org Lett 2022; 24:3337-3341. [PMID: 35510837 DOI: 10.1021/acs.orglett.2c00878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tabtoxin is a β-lactam ring-containing phytotoxin produced by a plant pathogenic Pseudomonas species. Here, we describe the early stages of tabtoxin biosynthesis, involving a C-methylation reaction catalyzed by the S-adenosyl-l-methionine-dependent methyltransferase TblA as the initial step for the β-lactam construction. Gene deletion and in vitro biochemical assays demonstrated that the Gcn5-related N-acetyltransferase domain of TblD catalyzes the acetylation of the α-amino group of 5-methyl-l-lysine. This establishment of the early reaction steps lays the foundation for characterizing unique β-lactam biosynthesis.
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Affiliation(s)
- Jiaqi Lyu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Richiro Ushimaru
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,ACT-X, Japan Science and Technology Agency (JST), Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Ikuro Abe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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Structural and molecular rationale for the diversification of resistance mediated by the Antibiotic_NAT family. Commun Biol 2022; 5:263. [PMID: 35338238 PMCID: PMC8956665 DOI: 10.1038/s42003-022-03219-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/23/2022] [Indexed: 11/08/2022] Open
Abstract
The environmental microbiome harbors a vast repertoire of antibiotic resistance genes (ARGs) which can serve as evolutionary predecessors for ARGs found in pathogenic bacteria, or can be directly mobilized to pathogens in the presence of selection pressures. Thus, ARGs from benign environmental bacteria are an important resource for understanding clinically relevant resistance. Here, we conduct a comprehensive functional analysis of the Antibiotic_NAT family of aminoglycoside acetyltransferases. We determined a pan-family antibiogram of 21 Antibiotic_NAT enzymes, including 8 derived from clinical isolates and 13 from environmental metagenomic samples. We find that environment-derived representatives confer high-level, broad-spectrum resistance, including against the atypical aminoglycoside apramycin, and that a metagenome-derived gene likely is ancestral to an aac(3) gene found in clinical isolates. Through crystallographic analysis, we rationalize the molecular basis for diversification of substrate specificity across the family. This work provides critical data on the molecular mechanism underpinning resistance to established and emergent aminoglycoside antibiotics and broadens our understanding of ARGs in the environment.
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Lammers M. Post-translational Lysine Ac(et)ylation in Bacteria: A Biochemical, Structural, and Synthetic Biological Perspective. Front Microbiol 2021; 12:757179. [PMID: 34721364 PMCID: PMC8556138 DOI: 10.3389/fmicb.2021.757179] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/10/2021] [Indexed: 12/21/2022] Open
Abstract
Ac(et)ylation is a post-translational modification present in all domains of life. First identified in mammals in histones to regulate RNA synthesis, today it is known that is regulates fundamental cellular processes also in bacteria: transcription, translation, metabolism, cell motility. Ac(et)ylation can occur at the ε-amino group of lysine side chains or at the α-amino group of a protein. Furthermore small molecules such as polyamines and antibiotics can be acetylated and deacetylated enzymatically at amino groups. While much research focused on N-(ε)-ac(et)ylation of lysine side chains, much less is known about the occurrence, the regulation and the physiological roles on N-(α)-ac(et)ylation of protein amino termini in bacteria. Lysine ac(et)ylation was shown to affect protein function by various mechanisms ranging from quenching of the positive charge, increasing the lysine side chains’ size affecting the protein surface complementarity, increasing the hydrophobicity and by interfering with other post-translational modifications. While N-(ε)-lysine ac(et)ylation was shown to be reversible, dynamically regulated by lysine acetyltransferases and lysine deacetylases, for N-(α)-ac(et)ylation only N-terminal acetyltransferases were identified and so far no deacetylases were discovered neither in bacteria nor in mammals. To this end, N-terminal ac(et)ylation is regarded as being irreversible. Besides enzymatic ac(et)ylation, recent data showed that ac(et)ylation of lysine side chains and of the proteins N-termini can also occur non-enzymatically by the high-energy molecules acetyl-coenzyme A and acetyl-phosphate. Acetyl-phosphate is supposed to be the key molecule that drives non-enzymatic ac(et)ylation in bacteria. Non-enzymatic ac(et)ylation can occur site-specifically with both, the protein primary sequence and the three dimensional structure affecting its efficiency. Ac(et)ylation is tightly controlled by the cellular metabolic state as acetyltransferases use ac(et)yl-CoA as donor molecule for the ac(et)ylation and sirtuin deacetylases use NAD+ as co-substrate for the deac(et)ylation. Moreover, the accumulation of ac(et)yl-CoA and acetyl-phosphate is dependent on the cellular metabolic state. This constitutes a feedback control mechanism as activities of many metabolic enzymes were shown to be regulated by lysine ac(et)ylation. Our knowledge on lysine ac(et)ylation significantly increased in the last decade predominantly due to the huge methodological advances that were made in fields such as mass-spectrometry, structural biology and synthetic biology. This also includes the identification of additional acylations occurring on lysine side chains with supposedly different regulatory potential. This review highlights recent advances in the research field. Our knowledge on enzymatic regulation of lysine ac(et)ylation will be summarized with a special focus on structural and mechanistic characterization of the enzymes, the mechanisms underlying non-enzymatic/chemical ac(et)ylation are explained, recent technological progress in the field are presented and selected examples highlighting the important physiological roles of lysine ac(et)ylation are summarized.
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Affiliation(s)
- Michael Lammers
- Synthetic and Structural Biochemistry, Institute for Biochemistry, University of Greifswald, Greifswald, Germany
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11
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Le VTB, Dang J, Lim EQ, Kuhn ML. Criticality of a conserved tyrosine residue in the SpeG protein from Escherichia coli. Protein Sci 2021; 30:1264-1269. [PMID: 33826189 DOI: 10.1002/pro.4078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/02/2021] [Accepted: 04/06/2021] [Indexed: 11/09/2022]
Abstract
The SpeG spermidine/spermine N-acetyltransferase (SSAT) from Escherichia coli belongs to the Gcn5-related N-acetyltransferase (GNAT) superfamily of proteins. In vitro characterization of this enzyme shows it acetylates the polyamines spermine and spermidine, with a preference toward spermine. This enzyme has a conserved tyrosine residue (Y135) that is found in all SSAT proteins and many GNAT functional subfamilies. It is located near acetyl coenzyme A in the active center of these proteins and has been suggested to act as a general acid in a general acid/base chemical mechanism. In contrast, a previous study showed this residue was not critical for E. coli SpeG enzymatic activity when mutated to phenylalanine. This result was quite different from previous studies with a comparable residue in the human and mouse SSAT proteins, which also acetylate spermine and spermidine. Therefore, we constructed several mutants of the E. coli SpeG Y135 residue and tested their enzymatic activity. We found this conserved residue was indeed critical for E. coli SpeG enzyme activity and may behave similarly in other SSAT proteins.
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Affiliation(s)
- Van Thi Bich Le
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California, USA
| | - Joseph Dang
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California, USA
| | - Ee Qi Lim
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California, USA
| | - Misty L Kuhn
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California, USA
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