1
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Fleming JR, Hauth F, Hartig JS, Mayans O. Crystal structure of a GCN5-related N-acetyltransferase from Lactobacillus curiae. Acta Crystallogr F Struct Biol Commun 2023; 79:217-223. [PMID: 37565839 PMCID: PMC10416765 DOI: 10.1107/s2053230x2300571x] [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: 04/25/2023] [Accepted: 06/29/2023] [Indexed: 08/12/2023] Open
Abstract
Members of the GCN5-related N-acetyltransferase (GNAT) family are found in all domains of life and are involved in processes ranging from protein synthesis and gene expression to detoxification and virulence. Due to the variety of their macromolecular targets, GNATs are a highly diverse family of proteins. Currently, 3D structures of only a small number of GNAT representatives are available and thus the family remains poorly characterized. Here, the crystal structure of the guanidine riboswitch-associated GNAT from Lactobacillus curiae (LcGNAT) that acetylates canavanine, a structural analogue of arginine with antimetabolite properties, is reported. LcGNAT shares the conserved fold of the members of the GNAT superfamily, but does not contain an N-terminal β0 strand and instead contains a C-terminal β7 strand. Its P-loop, which coordinates the pyrophosphate moiety of the acetyl-coenzyme A cosubstrate, is degenerated. These features are shared with its closest homologues in the polyamine acetyltransferase subclass. Site-directed mutagenesis revealed a central role of the conserved residue Tyr142 in catalysis, as well as the semi-conserved Tyr97 and Glu92, suggesting that despite its individual substrate specificity LcGNAT performs the classical reaction mechanism of this family.
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Affiliation(s)
- Jennifer R. Fleming
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Franziskus Hauth
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Jörg S. Hartig
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
| | - Olga Mayans
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
- Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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2
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Xu M, Liu X, Li X, Chen L, Li S, Sun B, Xu D, Ran T, Wang W. Crystal structure of prodigiosin binding protein PgbP, a GNAT family protein, in Serratia marcescens FS14. Biochem Biophys Res Commun 2023; 640:73-79. [PMID: 36502634 DOI: 10.1016/j.bbrc.2022.12.006] [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: 11/23/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022]
Abstract
Acetylation is a conserved modification catalyzed by acetyltransferases that play prominent roles in a large number of biological processes. Members of the general control non-repressible 5 (GCN5)-N-acetyltransferase (GNAT) protein superfamily are widespread in all kingdoms of life and are characterized by highly conserved catalytic fold, and can acetylate a wide range of substrates. Although the structures and functions of numerous eukaryotic GNATs have been identified thus far, many GNATs in microorganisms remain structurally and functionally undescribed. Here, we determined the crystal structure of the putative GCN5-N-acetyltransferase PgbP in complex with CoA in Serratia marcescens FS14. Structural analysis revealed that the PgbP dimer has two cavities, each of which binds a CoA molecule via conserved motifs of the GNAT family. In addition, the biochemical studies showed that PgbP is a prodigiosin-binding protein with high thermal stability. To our knowledge, this is the first view of GNAT binding to secondary metabolites and it is also the first report of prodigiosin binding protein. Molecular docking and mutation experiments indicated that prodigiosin binds to the substrate binding site of PgbP. The structure-function analyses presented here broaden our understanding of the multifunctionality of GNAT family members and may infer the mechanism of the multiple biological activities of prodigiosin.
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Affiliation(s)
- Mengxue Xu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Xia Liu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Xiaoyan Li
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Lin Chen
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Shengzhe Li
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China
| | - Bo Sun
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China; Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Dongqing Xu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China.
| | - Tingting Ran
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China.
| | - Weiwu Wang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, China.
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3
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Le VTB, Tsimbalyuk S, Lim EQ, Solis A, Gawat D, Boeck P, Lim EQ, Renolo R, Forwood JK, Kuhn ML. The Vibrio cholerae SpeG Spermidine/Spermine N-Acetyltransferase Allosteric Loop and β6-β7 Structural Elements Are Critical for Kinetic Activity. Front Mol Biosci 2021; 8:645768. [PMID: 33928120 PMCID: PMC8076852 DOI: 10.3389/fmolb.2021.645768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/16/2021] [Indexed: 11/27/2022] Open
Abstract
Polyamines regulate many important biological processes including gene expression, intracellular signaling, and biofilm formation. Their intracellular concentrations are tightly regulated by polyamine transport systems and biosynthetic and catabolic pathways. Spermidine/spermine N-acetyltransferases (SSATs) are catabolic enzymes that acetylate polyamines and are critical for maintaining intracellular polyamine homeostasis. These enzymes belong to the Gcn5-related N-acetyltransferase (GNAT) superfamily and adopt a highly conserved fold found across all kingdoms of life. SpeG is an SSAT protein found in a variety of bacteria, including the human pathogen Vibrio cholerae. This protein adopts a dodecameric structure and contains an allosteric site, making it unique compared to other SSATs. Currently, we have a limited understanding of the critical structural components of this protein that are required for its allosteric behavior. Therefore, we explored the importance of two key regions of the SpeG protein on its kinetic activity. To achieve this, we created various constructs of the V. cholerae SpeG protein, including point mutations, a deletion, and chimeras with residues from the structurally distinct and non-allosteric human SSAT protein. We measured enzyme kinetic activity toward spermine for ten constructs and crystallized six of them. Ultimately, we identified specific portions of the allosteric loop and the β6-β7 structural elements that were critical for enzyme kinetic activity. These results provide a framework for further study of the structure/function relationship of SpeG enzymes from other organisms and clues toward the structural evolution of members of the GNAT family across domains of life.
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Affiliation(s)
- Van Thi Bich Le
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Sofiya Tsimbalyuk
- School of Biomedical Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Ee Qi Lim
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Allan Solis
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Darwin Gawat
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Paloma Boeck
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Ee Qing Lim
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Rosselini Renolo
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
| | - Jade K. Forwood
- School of Biomedical Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Misty L. Kuhn
- Department of Chemistry & Biochemistry, San Francisco State University, San Francisco, CA, United States
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4
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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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5
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Small-Molecule Acetylation by GCN5-Related N-Acetyltransferases in Bacteria. Microbiol Mol Biol Rev 2020; 84:84/2/e00090-19. [PMID: 32295819 DOI: 10.1128/mmbr.00090-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acetylation is a conserved modification used to regulate a variety of cellular pathways, such as gene expression, protein synthesis, detoxification, and virulence. Acetyltransferase enzymes transfer an acetyl moiety, usually from acetyl coenzyme A (AcCoA), onto a target substrate, thereby modulating activity or stability. Members of the GCN5- N -acetyltransferase (GNAT) protein superfamily are found in all domains of life and are characterized by a core structural domain architecture. These enzymes can modify primary amines of small molecules or of lysyl residues of proteins. From the initial discovery of antibiotic acetylation, GNATs have been shown to modify a myriad of small-molecule substrates, including tRNAs, polyamines, cell wall components, and other toxins. This review focuses on the literature on small-molecule substrates of GNATs in bacteria, including structural examples, to understand ligand binding and catalysis. Understanding the plethora and versatility of substrates helps frame the role of acetylation within the larger context of bacterial cellular physiology.
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6
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Goswami G, Panda D, Samanta R, Boro RC, Modi MK, Bujarbaruah KM, Barooah M. Bacillus megaterium adapts to acid stress condition through a network of genes: Insight from a genome-wide transcriptome analysis. Sci Rep 2018; 8:16105. [PMID: 30382109 PMCID: PMC6208408 DOI: 10.1038/s41598-018-34221-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 10/05/2018] [Indexed: 11/18/2022] Open
Abstract
RNA-seq analysis of B. megaterium exposed to pH 7.0 and pH 4.5 showed differential expression of 207 genes related to several processes. Among the 207 genes, 11 genes displayed increased transcription exclusively in pH 4.5. Exposure to pH 4.5 induced the expression of genes related to maintenance of cell integrity, pH homeostasis, alternative energy generation and modification of metabolic processes. Metabolic processes like pentose phosphate pathway, fatty acid biosynthesis, cysteine and methionine metabolism and synthesis of arginine and proline were remodeled during acid stress. Genes associated with oxidative stress and osmotic stress were up-regulated at pH 4.5 indicating a link between acid stress and other stresses. Acid stress also induced expression of genes that encoded general stress-responsive proteins as well as several hypothetical proteins. Our study indicates that a network of genes aid B. megaterium G18 to adapt and survive in acid stress condition.
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Affiliation(s)
- Gunajit Goswami
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India.,Department of Life-Sciences, Dibrugarh University, Dibrugarh, 786004, Assam, India
| | - Debashis Panda
- Distributed Information Centre, Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India
| | - Ramkrishna Samanta
- Department of Life-Sciences, Dibrugarh University, Dibrugarh, 786004, Assam, India
| | - Robin Chandra Boro
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India
| | - Mahendra Kumar Modi
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India.,Distributed Information Centre, Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India
| | - Kamal Malla Bujarbaruah
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India
| | - Madhumita Barooah
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India.
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7
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Aboalroub AA, Bachman AB, Zhang Z, Keramisanou D, Merkler DJ, Gelis I. Acetyl group coordinated progression through the catalytic cycle of an arylalkylamine N-acetyltransferase. PLoS One 2017; 12:e0177270. [PMID: 28486510 PMCID: PMC5423648 DOI: 10.1371/journal.pone.0177270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/25/2017] [Indexed: 11/18/2022] Open
Abstract
The transfer of an acetyl group from acetyl-CoA to an acceptor amine is a ubiquitous biochemical transformation catalyzed by Gcn5-related N-acetyltransferases (GNATs). Although it is established that the reaction proceeds through a sequential ordered mechanism, the role of the acetyl group in driving the ordered formation of binary and ternary complexes remains elusive. Herein, we show that CoA and acetyl-CoA alter the conformation of the substrate binding site of an arylalkylamine N-acetyltransferase (AANAT) to facilitate interaction with acceptor substrates. However, it is the presence of the acetyl group within the catalytic funnel that triggers high affinity binding. Acetyl group occupancy is relayed through a conserved salt bridge between the P-loop and the acceptor binding site, and is manifested as differential dynamics in the CoA and acetyl-CoA-bound states. The capacity of the acetyl group carried by an acceptor to promote its tight binding even in the absence of CoA, but also its mutually exclusive position to the acetyl group of acetyl-CoA underscore its importance in coordinating the progression of the catalytic cycle.
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Affiliation(s)
- Adam A. Aboalroub
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Ashleigh B. Bachman
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Ziming Zhang
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Dimitra Keramisanou
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - David J. Merkler
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Ioannis Gelis
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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8
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Young BH, Caldwell TA, McKenzie AM, Kokhan O, Berndsen CE. Characterization of the structure and catalytic activity of Legionella pneumophila VipF. Proteins 2016; 84:1422-30. [PMID: 27315603 DOI: 10.1002/prot.25087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/31/2016] [Accepted: 06/13/2016] [Indexed: 11/05/2022]
Abstract
The pathogenic bacteria Legionella pneumophila is known to cause Legionnaires' Disease, a severe pneumonia that can be fatal to immunocompromised individuals and the elderly. Shohdy et al. identified the L. pneumophila vacuole sorting inhibitory protein VipF as a putative N-acetyltransferase based on sequence homology. We have characterized the basic structural and functional properties of VipF to confirm this original functional assignment. Sequence conservation analysis indicates two putative CoA-binding regions within VipF. Homology modeling and small angle X-ray scattering suggest a monomeric, dual-domain structure joined by a flexible linker. Each domain contains the characteristic beta-splay motif found in many acetyltransferases, suggesting that VipF may contain two active sites. Docking experiments suggest reasonable acetyl-CoA binding locations within each beta-splay motif. Broad substrate screening indicated that VipF is capable of acetylating chloramphenicol and both domains are catalytically active. Given that chloramphenicol is not known to be N-acetylated, this is a surprising finding suggesting that VipF is capable of O-acetyltransferase activity. Proteins 2016; 84:1422-1430. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Byron H Young
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, 22807
| | - Tracy A Caldwell
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, 22807
| | - Aidan M McKenzie
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, 22807
| | - Oleksandr Kokhan
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, 22807
| | - Christopher E Berndsen
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia, 22807.
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9
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Salah Ud-Din AIM, Tikhomirova A, Roujeinikova A. Structure and Functional Diversity of GCN5-Related N-Acetyltransferases (GNAT). Int J Mol Sci 2016; 17:E1018. [PMID: 27367672 PMCID: PMC4964394 DOI: 10.3390/ijms17071018] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 06/14/2016] [Accepted: 06/20/2016] [Indexed: 12/17/2022] Open
Abstract
General control non-repressible 5 (GCN5)-related N-acetyltransferases (GNAT) catalyze the transfer of an acyl moiety from acyl coenzyme A (acyl-CoA) to a diverse group of substrates and are widely distributed in all domains of life. This review of the currently available data acquired on GNAT enzymes by a combination of structural, mutagenesis and kinetic methods summarizes the key similarities and differences between several distinctly different families within the GNAT superfamily, with an emphasis on the mechanistic insights obtained from the analysis of the complexes with substrates or inhibitors. It discusses the structural basis for the common acetyltransferase mechanism, outlines the factors important for the substrate recognition, and describes the mechanism of action of inhibitors of these enzymes. It is anticipated that understanding of the structural basis behind the reaction and substrate specificity of the enzymes from this superfamily can be exploited in the development of novel therapeutics to treat human diseases and combat emerging multidrug-resistant microbial infections.
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Affiliation(s)
- Abu Iftiaf Md Salah Ud-Din
- Infection and Immunity Program, Monash Biomedicine Discovery Institute; Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
| | - Alexandra Tikhomirova
- Infection and Immunity Program, Monash Biomedicine Discovery Institute; Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
| | - Anna Roujeinikova
- Infection and Immunity Program, Monash Biomedicine Discovery Institute; Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
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10
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Favrot L, Blanchard JS, Vergnolle O. Bacterial GCN5-Related N-Acetyltransferases: From Resistance to Regulation. Biochemistry 2016; 55:989-1002. [PMID: 26818562 DOI: 10.1021/acs.biochem.5b01269] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The GCN5-related N-acetyltransferases family (GNAT) is an important family of proteins that includes more than 100000 members among eukaryotes and prokaryotes. Acetylation appears as a major regulatory post-translational modification and is as widespread as phosphorylation. N-Acetyltransferases transfer an acetyl group from acetyl-CoA to a large array of substrates, from small molecules such as aminoglycoside antibiotics to macromolecules. Acetylation of proteins can occur at two different positions, either at the amino-terminal end (αN-acetylation) or at the ε-amino group (εN-acetylation) of an internal lysine residue. GNAT members have been classified into different groups on the basis of their substrate specificity, and in spite of a very low primary sequence identity, GNAT proteins display a common and conserved fold. This Current Topic reviews the different classes of bacterial GNAT proteins, their functions, their structural characteristics, and their mechanism of action.
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Affiliation(s)
- Lorenza Favrot
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - John S Blanchard
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Olivia Vergnolle
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
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11
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Chang YY, Hsu CH. Structural basis for substrate-specific acetylation of Nα-acetyltransferase Ard1 from Sulfolobus solfataricus. Sci Rep 2015; 5:8673. [PMID: 25728374 PMCID: PMC5390088 DOI: 10.1038/srep08673] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/29/2015] [Indexed: 11/18/2022] Open
Abstract
Nα-acetyltransferases (Nats) possess a wide range of important biological functions. Their structures can vary according to the first two residues of their substrate. However, the mechanisms of substrate recognition and catalysis of Nats are elusive. Here, we present two structure of Sulfolobus solfataricus Ard1 (SsArd1), a member of the NatA family, at 2.13 and 1.84 Å. Both structures contain coenzyme A, while the latter also contains a substrate-derived peptide. Sequential structure-based mutagenesis revealed that mutations of critical residues for CoA binding decreased the binding affinity of SsArd1 by 3 ~ 7-fold. Superimposition of SsArd1 (NatA) with human Naa50p (NatE) showed significant differences in key residues of enzymes near the first amino-acid position of the substrate peptide (Glu35 for SsArd1 and Val29 for Naa50p). Further enzyme activity assays revealed that the substrate specificity of SsArd1 could be altered from SSGTPT to MEEKVG by a range of Glu35 mutants. These studies provide not only a molecular elucidation of substrate recognition and specificity for the NatA family, but also insight into how members of the NAT family distinguish between amino acids at the substrate N-terminus from the ancient monomeric archaeal Ard1.
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Affiliation(s)
- Yu-Yung Chang
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Chun-Hua Hsu
- Department of Agricultural Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Center for Systems Biology; Genome and Systems Biology Degree Program, National Taiwan University, Taipei 10617, Taiwan
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12
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Kuhn ML, Majorek KA, Minor W, Anderson WF. Broad-substrate screen as a tool to identify substrates for bacterial Gcn5-related N-acetyltransferases with unknown substrate specificity. Protein Sci 2013; 22:222-30. [PMID: 23184347 PMCID: PMC3588918 DOI: 10.1002/pro.2199] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 11/15/2012] [Accepted: 11/15/2012] [Indexed: 12/21/2022]
Abstract
Due to a combination of efforts from individual laboratories and structural genomics centers, there has been a surge in the number of members of the Gcn5-related acetyltransferasesuperfamily that have been structurally determined within the past decade. Although the number of three-dimensional structures is increasing steadily, we know little about the individual functions of these enzymes. Part of the difficulty in assigning functions for members of this superfamily is the lack of information regarding how substrates bind to the active site of the protein. The majority of the structures do not show ligand bound in the active site, and since the substrate-binding domain is not strictly conserved, it is difficult to predict the function based on structure alone. Additionally, the enzymes are capable of acetylating a wide variety of metabolites and many may exhibit promiscuity regarding their ability to acetylate multiple classes of substrates, possibly having multiple functions for the same enzyme. Herein, we present an approach to identify potential substrates for previously uncharacterized members of the Gcn5-related acetyltransferase superfamily using a variety of metabolites including polyamines, amino acids, antibiotics, peptides, vitamins, catecholamines, and other metabolites. We have identified potential substrates for eight bacterial enzymes of this superfamily. This information will be used to further structurally and functionally characterize them.
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Affiliation(s)
- Misty L Kuhn
- Department of Pharmacology and Cellular Biology, Center for Structural Genomics of Infectious Diseases, Northwestern Feinberg School of MedicineChicago, Illinois 60611
| | - Karolina A Majorek
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesville, Virginia 22908
| | - Wladek Minor
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesville, Virginia 22908
| | - Wayne F Anderson
- Department of Pharmacology and Cellular Biology, Center for Structural Genomics of Infectious Diseases, Northwestern Feinberg School of MedicineChicago, Illinois 60611
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13
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Evolution of insect arylalkylamine N-acetyltransferases: structural evidence from the yellow fever mosquito, Aedes aegypti. Proc Natl Acad Sci U S A 2012; 109:11669-74. [PMID: 22753468 DOI: 10.1073/pnas.1206828109] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Arylalkylamine N-acetyltransferase (aaNAT) catalyzes the transacetylation from acetyl-CoA to arylalkylamines. aaNATs are involved in sclerotization and neurotransmitter inactivation in insects. Phyletic distribution analysis confirms three clusters of aaNAT-like sequences in insects: typical insect aaNAT, polyamine NAT-like aaNAT, and mosquito unique putative aaNAT (paaNAT). Here we studied three proteins: aaNAT2, aaNAT5b, and paaNAT7, each from a different cluster. aaNAT2, a protein from the typical insect aaNAT cluster, uses histamine as a substrate as well as the previously identified arylalkylamines. aaNAT5b, a protein from polyamine NAT -like aaNAT cluster, uses hydrazine and histamine as substrates. The crystal structure of aaNAT2 was determined using single-wavelength anomalous dispersion methods, and that of native aaNAT2, aaNAT5b and paaNAT7 was detected using molecular replacement techniques. All three aaNAT structures have a common fold core of GCN5-related N-acetyltransferase superfamily proteins, along with a unique structural feature: helix/helices between β3 and β4 strands. Our data provide a start toward a more comprehensive understanding of the structure-function relationship and physiology of aaNATs from the mosquito Aedes aegypti and serve as a reference for studying the aaNAT family of proteins from other insect species. The structures of three different types of aaNATs may provide targets for designing insecticides for use in mosquito control.
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