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Zheng X, Su C, Duan L, Jin M, Sun Y, Zhu L, Zhang W. Molecular basis of A. thaliana KEOPS complex in biosynthesizing tRNA t6A. Nucleic Acids Res 2024; 52:4523-4540. [PMID: 38477398 PMCID: PMC11077089 DOI: 10.1093/nar/gkae179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/19/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024] Open
Abstract
In archaea and eukaryotes, the evolutionarily conserved KEOPS is composed of four core subunits-Kae1, Bud32, Cgi121 and Pcc1, and a fifth Gon7/Pcc2 that is found in fungi and metazoa. KEOPS cooperates with Sua5/YRDC to catalyze the biosynthesis of tRNA N6-threonylcarbamoyladenosine (t6A), an essential modification needed for fitness of cellular organisms. Biochemical and structural characterizations of KEOPSs from archaea, yeast and humans have determined a t6A-catalytic role for Kae1 and auxiliary roles for other subunits. However, the precise molecular workings of KEOPSs still remain poorly understood. Here, we investigated the biochemical functions of A. thaliana KEOPS and determined a cryo-EM structure of A. thaliana KEOPS dimer. We show that A. thaliana KEOPS is composed of KAE1, BUD32, CGI121 and PCC1, which adopts a conserved overall arrangement. PCC1 dimerization leads to a KEOPS dimer that is needed for an active t6A-catalytic KEOPS-tRNA assembly. BUD32 participates in direct binding of tRNA to KEOPS and modulates the t6A-catalytic activity of KEOPS via its C-terminal tail and ATP to ADP hydrolysis. CGI121 promotes the binding of tRNA to KEOPS and potentiates the t6A-catalytic activity of KEOPS. These data and findings provide insights into mechanistic understanding of KEOPS machineries.
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Affiliation(s)
- Xinxing Zheng
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Chenchen Su
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Lei Duan
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Mengqi Jin
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Yongtao Sun
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Li Zhu
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Wenhua Zhang
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
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2
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Jin M, Zhang Z, Yu Z, Chen W, Wang X, Lei D, Zhang W. Structure-function analysis of an ancient TsaD-TsaC-SUA5-TcdA modular enzyme reveals a prototype of tRNA t6A and ct6A synthetases. Nucleic Acids Res 2023; 51:8711-8729. [PMID: 37427786 PMCID: PMC10484737 DOI: 10.1093/nar/gkad587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/22/2023] [Accepted: 06/29/2023] [Indexed: 07/11/2023] Open
Abstract
N 6-threonylcarbamoyladenosine (t6A) is a post-transcriptional modification found uniquely at position 37 of tRNAs that decipher ANN-codons in the three domains of life. tRNA t6A plays a pivotal role in promoting translational fidelity and maintaining protein homeostasis. The biosynthesis of tRNA t6A requires members from two evolutionarily conserved protein families TsaC/Sua5 and TsaD/Kae1/Qri7, and a varying number of auxiliary proteins. Furthermore, tRNA t6A is modified into a cyclic hydantoin form of t6A (ct6A) by TcdA in bacteria. In this work, we have identified a TsaD-TsaC-SUA5-TcdA modular protein (TsaN) from Pandoraviruses and determined a 3.2 Å resolution cryo-EM structure of P. salinus TsaN. The four domains of TsaN share strong structural similarities with TsaD/Kae1/Qri7 proteins, TsaC/Sua5 proteins, and Escherichia coli TcdA. TsaN catalyzes the formation of threonylcarbamoyladenylate (TC-AMP) using L-threonine, HCO3- and ATP, but does not participate further in tRNA t6A biosynthesis. We report for the first time that TsaN catalyzes a tRNA-independent threonylcarbamoyl modification of adenosine phosphates, leading to t6ADP and t6ATP. Moreover, TsaN is also active in catalyzing tRNA-independent conversion of t6A nucleoside to ct6A. Our results imply that TsaN from Pandoraviruses might be a prototype of the tRNA t6A- and ct6A-modifying enzymes in some cellular organisms.
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Affiliation(s)
- Mengqi Jin
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Zelin Zhang
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, China
| | - Zhijiang Yu
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Wei Chen
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Xiaolei Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Dongsheng Lei
- Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou 730000, China
| | - Wenhua Zhang
- School of Life Sciences, Key Laboratory of Cell Activities and Stress Adaptation of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
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Abstract
The study of eukaryotic tRNA processing has given rise to an explosion of new information and insights in the last several years. We now have unprecedented knowledge of each step in the tRNA processing pathway, revealing unexpected twists in biochemical pathways, multiple new connections with regulatory pathways, and numerous biological effects of defects in processing steps that have profound consequences throughout eukaryotes, leading to growth phenotypes in the yeast Saccharomyces cerevisiae and to neurological and other disorders in humans. This review highlights seminal new results within the pathways that comprise the life of a tRNA, from its birth after transcription until its death by decay. We focus on new findings and revelations in each step of the pathway including the end-processing and splicing steps, many of the numerous modifications throughout the main body and anticodon loop of tRNA that are so crucial for tRNA function, the intricate tRNA trafficking pathways, and the quality control decay pathways, as well as the biogenesis and biology of tRNA-derived fragments. We also describe the many interactions of these pathways with signaling and other pathways in the cell.
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Affiliation(s)
- Eric M Phizicky
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, Ohio State University, Columbus, Ohio 43235, USA
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4
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Wu P, Gan Q, Zhang X, Yang Y, Xiao Y, She Q, Ni J, Huang Q, Shen Y. The archaeal KEOPS complex possesses a functional Gon7 homolog and has an essential function independent of the cellular t 6A modification level. MLIFE 2023; 2:11-27. [PMID: 38818338 PMCID: PMC10989989 DOI: 10.1002/mlf2.12051] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 11/29/2022] [Indexed: 06/01/2024]
Abstract
Kinase, putative Endopeptidase, and Other Proteins of Small size (KEOPS) is a multisubunit protein complex conserved in eukaryotes and archaea. It is composed of Pcc1, Kae1, Bud32, Cgi121, and Gon7 in eukaryotes and is primarily involved in N6-threonylcarbamoyl adenosine (t6A) modification of transfer RNAs (tRNAs). Recently, it was reported that KEOPS participates in homologous recombination (HR) repair in yeast. To characterize the KEOPS in archaea (aKEOPS), we conducted genetic and biochemical analyses of its encoding genes in the hyperthermophilic archaeon Saccharolobus islandicus. We show that aKEOPS also possesses five subunits, Pcc1, Kae1, Bud32, Cgi121, and Pcc1-like (or Gon7-like), just like eukaryotic KEOPS. Pcc1-like has physical interactions with Kae1 and Pcc1 and can mediate the monomerization of the dimeric subcomplex (Kae1-Pcc1-Pcc1-Kae1), suggesting that Pcc1-like is a functional homolog of the eukaryotic Gon7 subunit. Strikingly, none of the genes encoding aKEOPS subunits, including Pcc1 and Pcc1-like, can be deleted in the wild type and in a t6A modification complementary strain named TsaKI, implying that the aKEOPS complex is essential for an additional cellular process in this archaeon. Knock-down of the Cgi121 subunit leads to severe growth retardance in the wild type that is partially rescued in TsaKI. These results suggest that aKEOPS plays an essential role independent of the cellular t6A modification level. In addition, archaeal Cgi121 possesses dsDNA-binding activity that relies on its tRNA 3' CCA tail binding module. Our study clarifies the subunit organization of archaeal KEOPS and suggests an origin of eukaryotic Gon7. The study also reveals a possible link between the function in t6A modification and the additional function, presumably HR.
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Affiliation(s)
- Pengju Wu
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Qi Gan
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Xuemei Zhang
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Yunfeng Yang
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Yuanxi Xiao
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Qunxin She
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Jinfeng Ni
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Qihong Huang
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
| | - Yulong Shen
- State Key Laboratory of Microbial Technology, CRISPR and Archaea Biology Research Center, Microbial Technology InstituteShandong UniversityQingdaoChina
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Conservation and Diversification of tRNA t6A-Modifying Enzymes across the Three Domains of Life. Int J Mol Sci 2022; 23:ijms232113600. [PMID: 36362385 PMCID: PMC9654439 DOI: 10.3390/ijms232113600] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 10/28/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
The universal N6-threonylcarbamoyladenosine (t6A) modification occurs at position 37 of tRNAs that decipher codons starting with adenosine. Mechanistically, t6A stabilizes structural configurations of the anticodon stem loop, promotes anticodon–codon pairing and safeguards the translational fidelity. The biosynthesis of tRNA t6A is co-catalyzed by two universally conserved protein families of TsaC/Sua5 (COG0009) and TsaD/Kae1/Qri7 (COG0533). Enzymatically, TsaC/Sua5 protein utilizes the substrates of L-threonine, HCO3−/CO2 and ATP to synthesize an intermediate L-threonylcarbamoyladenylate, of which the threonylcarbamoyl-moiety is subsequently transferred onto the A37 of substrate tRNAs by the TsaD–TsaB –TsaE complex in bacteria or by the KEOPS complex in archaea and eukaryotic cytoplasm, whereas Qri7/OSGEPL1 protein functions on its own in mitochondria. Depletion of tRNA t6A interferes with protein homeostasis and gravely affects the life of unicellular organisms and the fitness of higher eukaryotes. Pathogenic mutations of YRDC, OSGEPL1 and KEOPS are implicated in a number of human mitochondrial and neurological diseases, including autosomal recessive Galloway–Mowat syndrome. The molecular mechanisms underscoring both the biosynthesis and cellular roles of tRNA t6A are presently not well elucidated. This review summarizes current mechanistic understandings of the catalysis, regulation and disease implications of tRNA t6A-biosynthetic machineries of three kingdoms of life, with a special focus on delineating the structure–function relationship from perspectives of conservation and diversity.
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Wang JT, Zhou JB, Mao XL, Zhou L, Chen M, Zhang W, Wang ED, Zhou XL. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2223-2239. [PMID: 35104889 PMCID: PMC8887486 DOI: 10.1093/nar/gkac056] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/16/2022] [Accepted: 01/25/2022] [Indexed: 11/14/2022] Open
Abstract
N6-Threonylcarbamoyladenosine (t6A) is a universal and pivotal tRNA modification. KEOPS in eukaryotes participates in its biogenesis, whose mutations are connected with Galloway-Mowat syndrome. However, the tRNA substrate selection mechanism by KEOPS and t6A modification function in mammalian cells remain unclear. Here, we confirmed that all ANN-decoding human cytoplasmic tRNAs harbor a t6A moiety. Using t6A modification systems from various eukaryotes, we proposed the possible coevolution of position 33 of initiator tRNAMet and modification enzymes. The role of the universal CCA end in t6A biogenesis varied among species. However, all KEOPSs critically depended on C32 and two base pairs in the D-stem. Knockdown of the catalytic subunit OSGEP in HEK293T cells had no effect on the steady-state abundance of cytoplasmic tRNAs but selectively inhibited tRNAIle aminoacylation. Combined with in vitro aminoacylation assays, we revealed that t6A functions as a tRNAIle isoacceptor-specific positive determinant for human cytoplasmic isoleucyl-tRNA synthetase (IARS1). t6A deficiency had divergent effects on decoding efficiency at ANN codons and promoted +1 frameshifting. Altogether, our results shed light on the tRNA recognition mechanism, revealing both commonality and diversity in substrate recognition by eukaryotic KEOPSs, and elucidated the critical role of t6A in tRNAIle aminoacylation and codon decoding in human cells.
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Affiliation(s)
| | | | - Xue-Ling Mao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Li Zhou
- School of Life Sciences, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu
| | - Meirong Chen
- School of Pharmacy, China Pharmaceutical University, 639 Longmian Avenue, Nanjing 211198, Jiangsu
| | - Wenhua Zhang
- School of Life Sciences, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu
| | - En-Duo Wang
- Correspondence may also be addressed to En-Duo Wang. Tel: +86 21 5492 1241; Fax: +86 21 5492 1011;
| | - Xiao-Long Zhou
- To whom correspondence should be addressed. Tel: +86 21 5492 1247 Fax: +86 21 5492 1011;
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7
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Mathivanan J, Du J, Mao S, Zheng YY, Sheng J. Synthesis and Purification of N 3 -Methylcytidine (m 3 C) Modified RNA Oligonucleotides. Curr Protoc 2021; 1:e307. [PMID: 34792865 DOI: 10.1002/cpz1.307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This protocol describes a step-by-step chemical synthesis approach to prepare N3 -methylcytidine (m3 C) and its phosphoramidite. The method for synthesizing m3 C starts from commercially available cytidine, and proceeds via N3 -methylation in the presence of MeI, which generates the N3 -methylcytidine (m3 C) nucleoside, followed by the installation of several protecting groups at sites that include the 5'-hydroxyl group (4,4'-dimethoxytrityl protection), the 4-amino group (benzoyl protection), and the 2'-hydroxyl group (tert-butyldimethylsilyl, TBDMS, protection). Standard phosphoramidite chemistry is applied to prepare the final m3 C phosphoramidite for solid-phase synthesis of a series of RNA oligonucleotides. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of N3 -methylcytidine (m3 C) and its phosphoramidite Basic Protocol 2: Automated synthesis of m3 C modified RNA oligonucleotides.
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Affiliation(s)
- Johnsi Mathivanan
- Department of Chemistry and the RNA Institute, University at Albany, State University of New York, Albany, New York
| | - Jinxi Du
- Department of Chemistry and the RNA Institute, University at Albany, State University of New York, Albany, New York
| | - Song Mao
- Department of Chemistry and the RNA Institute, University at Albany, State University of New York, Albany, New York
| | - Ya Ying Zheng
- Department of Chemistry and the RNA Institute, University at Albany, State University of New York, Albany, New York
| | - Jia Sheng
- Department of Chemistry and the RNA Institute, University at Albany, State University of New York, Albany, New York
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8
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Metal utilization in genome-reduced bacteria: Do human mycoplasmas rely on iron? Comput Struct Biotechnol J 2021; 19:5752-5761. [PMID: 34765092 PMCID: PMC8566771 DOI: 10.1016/j.csbj.2021.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 12/04/2022] Open
Abstract
Mycoplasmas are parasitic bacteria with streamlined genomes and complex nutritional requirements. Although iron is vital for almost all organisms, its utilization by mycoplasmas is controversial. Despite its minimalist nature, mycoplasmas can survive and persist within the host, where iron availability is rigorously restricted through nutritional immunity. In this review, we describe the putative iron-enzymes, transporters, and metalloregulators of four relevant human mycoplasmas. This work brings in light critical differences in the mycoplasma-iron interplay. Mycoplasma penetrans, the species with the largest genome (1.36 Mb), shows a more classic repertoire of iron-related proteins, including different enzymes using iron-sulfur clusters as well as iron storage and transport systems. In contrast, the iron requirement is less apparent in the three species with markedly reduced genomes, Mycoplasma genitalium (0.58 Mb), Mycoplasma hominis (0.67 Mb) and Mycoplasma pneumoniae (0.82 Mb), as they exhibit only a few proteins possibly involved in iron homeostasis. The multiple facets of iron metabolism in mycoplasmas illustrate the remarkable evolutive potential of these minimal organisms when facing nutritional immunity and question the dependence of several human-infecting species for iron. Collectively, our data contribute to better understand the unique biology and infective strategies of these successful pathogens.
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Key Words
- ABC, ATP-binding cassette
- ECF transporter
- ECF, energy-coupling factor
- Fur, ferric uptake regulator
- Hrl, histidine-rich lipoprotein
- Iron homeostasis
- Metal acquisition
- Metalloenzyme
- Mge, Mycoplasma genitalium
- Mho, Mycoplasma hominis
- Mollicutes
- Mpe, Mycoplasma penetrans
- Mpn, Mycoplasma pneumonia
- Mycoplasmas
- PDB, protein data bank
- RNR, ribonucleotide reductase
- XRF, X-ray fluorescence
- ZIP, zinc-iron permease
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Beenstock J, Sicheri F. The structural and functional workings of KEOPS. Nucleic Acids Res 2021; 49:10818-10834. [PMID: 34614169 PMCID: PMC8565320 DOI: 10.1093/nar/gkab865] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/09/2021] [Accepted: 10/04/2021] [Indexed: 11/14/2022] Open
Abstract
KEOPS (Kinase, Endopeptidase and Other Proteins of Small size) is a five-subunit protein complex that is highly conserved in eukaryotes and archaea and is essential for the fitness of cells and for animal development. In humans, mutations in KEOPS genes underlie Galloway-Mowat syndrome, which manifests in severe microcephaly and renal dysfunction that lead to childhood death. The Kae1 subunit of KEOPS catalyzes the universal and essential tRNA modification N6-threonylcarbamoyl adenosine (t6A), while the auxiliary subunits Cgi121, the kinase/ATPase Bud32, Pcc1 and Gon7 play a supporting role. Kae1 orthologs are also present in bacteria and mitochondria but function in distinct complexes with proteins that are not related in structure or function to the auxiliary subunits of KEOPS. Over the past 15 years since its discovery, extensive study in the KEOPS field has provided many answers towards understanding the roles that KEOPS plays in cells and in human disease and how KEOPS carries out these functions. In this review, we provide an overview into recent advances in the study of KEOPS and illuminate exciting future directions.
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Affiliation(s)
- Jonah Beenstock
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Frank Sicheri
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, Ontario, M5S 1A8, Canada.,Department of Biochemistry, University of Toronto, Ontario, M5S 1A8, Canada
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10
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Hussain H, McKenzie EA, Robinson AM, Gingles NA, Marston F, Warwicker J, Dickson AJ. Predictive approaches to guide the expression of recombinant vaccine targets in Escherichia coli: a case study presentation utilising Absynth Biologics Ltd. proprietary Clostridium difficile vaccine antigens. Appl Microbiol Biotechnol 2021; 105:5657-5674. [PMID: 34180005 PMCID: PMC8285303 DOI: 10.1007/s00253-021-11405-9] [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: 04/28/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 12/01/2022]
Abstract
Bacterial expression systems remain a widely used host for recombinant protein production. However, overexpression of recombinant target proteins in bacterial systems such as Escherichia coli can result in poor solubility and the formation of insoluble aggregates. As a consequence, numerous strategies or alternative engineering approaches have been employed to increase recombinant protein production. In this case study, we present the strategies used to increase the recombinant production and solubility of ‘difficult-to-express’ bacterial antigens, termed Ant2 and Ant3, from Absynth Biologics Ltd.’s Clostridium difficile vaccine programme. Single recombinant antigens (Ant2 and Ant3) and fusion proteins (Ant2-3 and Ant3-2) formed insoluble aggregates (inclusion bodies) when overexpressed in bacterial cells. Further, proteolytic cleavage of Ant2-3 was observed. Optimisation of culture conditions and changes to the construct design to include N-terminal solubility tags did not improve antigen solubility. However, screening of different buffer/additives showed that the addition of 1–15 mM dithiothreitol alone decreased the formation of insoluble aggregates and improved the stability of both Ant2 and Ant3. Structural models were generated for Ant2 and Ant3, and solubility-based prediction tools were employed to determine the role of hydrophobicity and charge on protein production. The results showed that a large non-polar region (containing hydrophobic amino acids) was detected on the surface of Ant2 structures, whereas positively charged regions (containing lysine and arginine amino acids) were observed for Ant3, both of which were associated with poor protein solubility. We present a guide of strategies and predictive approaches that aim to guide the construct design, prior to expression studies, to define and engineer sequences/structures that could lead to increased expression and stability of single and potentially multi-domain (or fusion) antigens in bacterial expression systems.
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Affiliation(s)
- Hirra Hussain
- Manchester Institute of Biotechnology, University of Manchester, M1 7DN, Manchester, UK
| | - Edward A McKenzie
- Manchester Institute of Biotechnology, University of Manchester, M1 7DN, Manchester, UK
| | - Andrew M Robinson
- Absynth Biologics Ltd., BioHub, Alderley Park, Cheshire, SK10 4TG, UK.,Evotec Limited, Biohub, Alderley Park, Cheshire, England, SK10 4TG, UK
| | - Neill A Gingles
- Absynth Biologics Ltd., BioHub, Alderley Park, Cheshire, SK10 4TG, UK.,metaLinear Limited, Biohub, Alderley Park, Cheshire, England, SK10 4TG, UK
| | - Fiona Marston
- Absynth Biologics Ltd., BioHub, Alderley Park, Cheshire, SK10 4TG, UK.,Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Jim Warwicker
- Manchester Institute of Biotechnology, University of Manchester, M1 7DN, Manchester, UK
| | - Alan J Dickson
- Manchester Institute of Biotechnology, University of Manchester, M1 7DN, Manchester, UK.
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11
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Kopina BJ, Missoury S, Collinet B, Fulton MG, Cirio C, van Tilbeurgh H, Lauhon CT. Structure of a reaction intermediate mimic in t6A biosynthesis bound in the active site of the TsaBD heterodimer from Escherichia coli. Nucleic Acids Res 2021; 49:2141-2160. [PMID: 33524148 PMCID: PMC7913687 DOI: 10.1093/nar/gkab026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/21/2020] [Accepted: 01/15/2021] [Indexed: 11/14/2022] Open
Abstract
The tRNA modification N6-threonylcarbamoyladenosine (t6A) is universally conserved in all organisms. In bacteria, the biosynthesis of t6A requires four proteins (TsaBCDE) that catalyze the formation of t6A via the unstable intermediate l-threonylcarbamoyl-adenylate (TC-AMP). While the formation and stability of this intermediate has been studied in detail, the mechanism of its transfer to A37 in tRNA is poorly understood. To investigate this step, the structure of the TsaBD heterodimer from Escherichia coli has been solved bound to a stable phosphonate isosteric mimic of TC-AMP. The phosphonate inhibits t6A synthesis in vitro with an IC50 value of 1.3 μM in the presence of millimolar ATP and L-threonine. The inhibitor binds to TsaBD by coordination to the active site Zn atom via an oxygen atom from both the phosphonate and the carboxylate moieties. The bound conformation of the inhibitor suggests that the catalysis exploits a putative oxyanion hole created by a conserved active site loop of TsaD and that the metal essentially serves as a binding scaffold for the intermediate. The phosphonate bound crystal structure should be useful for the rational design of potent, drug-like small molecule inhibitors as mechanistic probes or potentially novel antibiotics.
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Affiliation(s)
- Brett J Kopina
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Sophia Missoury
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Bruno Collinet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.,Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne-Université, UMR7590 CNRS, MNHN, Paris, France
| | - Mark G Fulton
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Charles Cirio
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Herman van Tilbeurgh
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Charles T Lauhon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
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12
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Abstract
Mutations of the p53-related protein kinase (PRPK) and TP53RK-binding protein (TPRKB) cause Galloway-Mowat syndrome (GAMOS) and are found in various human cancers. We have previously shown that small compounds targeting PRPK showed anti-cancer activity against colon and skin cancer. Here we present the 2.53 Å crystal structure of the human PRPK-TPRKB-AMPPNP (adenylyl-imidodiphosphate) complex. The structure reveals details in PRPK-AMPPNP coordination and PRPK-TPRKB interaction. PRPK appears in an active conformation, albeit lacking the conventional kinase activation loop. We constructed a structural model of the human EKC/KEOPS complex, composed of PRPK, TPRKB, OSGEP, LAGE3, and GON7. Disease mutations in PRPK and TPRKB are mapped into the structure, and we show that one mutation, PRPK K238Nfs*2, lost the binding to OSGEP. Our structure also makes the virtual screening possible and paves the way for more rational drug design. Jian Li and Xinli Ma et al. present a 2.53 Å crystal structure of a complex consisting of the human p53-related protein kinase (PRPK), TP53RK-binding protein, and adenylyl-imidodiphosphate. They find that one disease mutation, PRPK K238Nfs*2, is important for PRPK’s binding to O-sialoglycoprotein endopeptidase, providing insights into rational drug design.
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13
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A substrate binding model for the KEOPS tRNA modifying complex. Nat Commun 2020; 11:6233. [PMID: 33277478 PMCID: PMC7718258 DOI: 10.1038/s41467-020-19990-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/02/2020] [Indexed: 11/09/2022] Open
Abstract
The KEOPS complex, which is conserved across archaea and eukaryotes, is composed of four core subunits; Pcc1, Kae1, Bud32 and Cgi121. KEOPS is crucial for the fitness of all organisms examined. In humans, pathogenic mutations in KEOPS genes lead to Galloway-Mowat syndrome, an autosomal-recessive disease causing childhood lethality. Kae1 catalyzes the universal and essential tRNA modification N6-threonylcarbamoyl adenosine, but the precise roles of all other KEOPS subunits remain an enigma. Here we show using structure-guided studies that Cgi121 recruits tRNA to KEOPS by binding to its 3' CCA tail. A composite model of KEOPS bound to tRNA reveals that all KEOPS subunits form an extended tRNA-binding surface that we have validated in vitro and in vivo to mediate the interaction with the tRNA substrate and its modification. These findings provide a framework for understanding the inner workings of KEOPS and delineate why all KEOPS subunits are essential.
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14
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Li W, Chang STL, Ward FR, Cate JHD. Selective inhibition of human translation termination by a drug-like compound. Nat Commun 2020; 11:4941. [PMID: 33009412 PMCID: PMC7532171 DOI: 10.1038/s41467-020-18765-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/11/2020] [Indexed: 02/08/2023] Open
Abstract
Methods to directly inhibit gene expression using small molecules hold promise for the development of new therapeutics targeting proteins that have evaded previous attempts at drug discovery. Among these, small molecules including the drug-like compound PF-06446846 (PF846) selectively inhibit the synthesis of specific proteins, by stalling translation elongation. These molecules also inhibit translation termination by an unknown mechanism. Using cryo-electron microscopy (cryo-EM) and biochemical approaches, we show that PF846 inhibits translation termination by arresting the nascent chain (NC) in the ribosome exit tunnel. The arrested NC adopts a compact α-helical conformation that induces 28 S rRNA nucleotide rearrangements that suppress the peptidyl transferase center (PTC) catalytic activity stimulated by eukaryotic release factor 1 (eRF1). These data support a mechanism of action for a small molecule targeting translation that suppresses peptidyl-tRNA hydrolysis promoted by eRF1, revealing principles of eukaryotic translation termination and laying the foundation for new therapeutic strategies.
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Affiliation(s)
- Wenfei Li
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, 94720, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Stacey Tsai-Lan Chang
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, 94720, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, 94720, USA
| | - Fred R Ward
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, 94720, USA
| | - Jamie H D Cate
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, 94720, USA.
- Innovative Genomics Institute, University of California, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Department of Chemistry, University of California, Berkeley, CA, USA.
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15
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Swinehart W, Deutsch C, Sarachan KL, Luthra A, Bacusmo JM, de Crécy-Lagard V, Swairjo MA, Agris PF, Iwata-Reuyl D. Specificity in the biosynthesis of the universal tRNA nucleoside N6-threonylcarbamoyl adenosine (t 6A)-TsaD is the gatekeeper. RNA (NEW YORK, N.Y.) 2020; 26:1094-1103. [PMID: 32385138 PMCID: PMC7430679 DOI: 10.1261/rna.075747.120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
N6-threonylcarbamoyl adenosine (t6A) is a nucleoside modification found in all kingdoms of life at position 37 of tRNAs decoding ANN codons, which functions in part to restrict translation initiation to AUG and suppress frameshifting at tandem ANN codons. In Bacteria the proteins TsaB, TsaC (or C2), TsaD, and TsaE, comprise the biosynthetic apparatus responsible for t6A formation. TsaC(C2) and TsaD harbor the relevant active sites, with TsaC(C2) catalyzing the formation of the intermediate threonylcarbamoyladenosine monophosphate (TC-AMP) from ATP, threonine, and CO2, and TsaD catalyzing the transfer of the threonylcarbamoyl moiety from TC-AMP to A37 of substrate tRNAs. Several related modified nucleosides, including hydroxynorvalylcarbamoyl adenosine (hn6A), have been identified in select organisms, but nothing is known about their biosynthesis. To better understand the mechanism and structural constraints on t6A formation, and to determine if related modified nucleosides are formed via parallel biosynthetic pathways or the t6A pathway, we carried out biochemical and biophysical investigations of the t6A systems from E. coli and T. maritima to address these questions. Using kinetic assays of TsaC(C2), tRNA modification assays, and NMR, our data demonstrate that TsaC(C2) exhibit relaxed substrate specificity, producing a variety of TC-AMP analogs that can differ in both the identity of the amino acid and nucleotide component, whereas TsaD displays more stringent specificity, but efficiently produces hn6A in E. coli and T. maritima tRNA. Thus, in organisms that contain modifications such as hn6A in their tRNA, we conclude that their origin is due to formation via the t6A pathway.
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Affiliation(s)
- William Swinehart
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
| | - Christopher Deutsch
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
| | - Kathryn L Sarachan
- The RNA Institute, State University of New York, Albany, New York 12222, USA
| | - Amit Luthra
- Department of Chemistry and Biochemistry, and The Viral Information Institute, San Diego State University, San Diego, California 92182, USA
| | - Jo Marie Bacusmo
- Department of Microbiology and Cell Science, University of Florida, Gainsville, Florida 32611, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainsville, Florida 32611, USA
| | - Manal A Swairjo
- Department of Chemistry and Biochemistry, and The Viral Information Institute, San Diego State University, San Diego, California 92182, USA
| | - Paul F Agris
- The RNA Institute, State University of New York, Albany, New York 12222, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
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16
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Zhou JB, Wang Y, Zeng QY, Meng SX, Wang ED, Zhou XL. Molecular basis for t6A modification in human mitochondria. Nucleic Acids Res 2020; 48:3181-3194. [PMID: 32047918 PMCID: PMC7102964 DOI: 10.1093/nar/gkaa093] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 12/27/2022] Open
Abstract
N6-Threonylcarbamoyladenosine (t6A) is a universal tRNA modification essential for translational accuracy and fidelity. In human mitochondria, YrdC synthesises an l-threonylcarbamoyl adenylate (TC-AMP) intermediate, and OSGEPL1 transfers the TC-moiety to five tRNAs, including human mitochondrial tRNAThr (hmtRNAThr). Mutation of hmtRNAs, YrdC and OSGEPL1, affecting efficient t6A modification, has been implicated in various human diseases. However, little is known about the tRNA recognition mechanism in t6A formation in human mitochondria. Herein, we showed that OSGEPL1 is a monomer and is unique in utilising C34 as an anti-determinant by studying the contributions of individual bases in the anticodon loop of hmtRNAThr to t6A modification. OSGEPL1 activity was greatly enhanced by introducing G38A in hmtRNAIle or the A28:U42 base pair in a chimeric tRNA containing the anticodon stem of hmtRNASer(AGY), suggesting that sequences of specific hmtRNAs are fine-tuned for different modification levels. Moreover, using purified OSGEPL1, we identified multiple acetylation sites, and OSGEPL1 activity was readily affected by acetylation via multiple mechanisms in vitro and in vivo. Collectively, we systematically elucidated the nucleotide requirement in the anticodon loop of hmtRNAs, and revealed mechanisms involving tRNA sequence optimisation and post-translational protein modification that determine t6A modification levels.
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Affiliation(s)
- Jing-Bo Zhou
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Yong Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.,School of Life Science and Technology, ShanghaiTech University, 100 Hai Ke Road, Shanghai 201210, China
| | - Qi-Yu Zeng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Shi-Xin Meng
- Biology Department, College of Science, Purdue University, 150 N. University St, West Lafayette, IN 47907, USA
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.,School of Life Science and Technology, ShanghaiTech University, 100 Hai Ke Road, Shanghai 201210, China
| | - Xiao-Long Zhou
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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17
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Missoury S, Plancqueel S, Li de la Sierra-Gallay I, Zhang W, Liger D, Durand D, Dammak R, Collinet B, van Tilbeurgh H. The structure of the TsaB/TsaD/TsaE complex reveals an unexpected mechanism for the bacterial t6A tRNA-modification. Nucleic Acids Res 2019; 47:9464-9465. [PMID: 31428791 PMCID: PMC6755083 DOI: 10.1093/nar/gkz719] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Sophia Missoury
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Stéphane Plancqueel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Ines Li de la Sierra-Gallay
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Wenhua Zhang
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Dominique Liger
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Raoudha Dammak
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
| | - Bruno Collinet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France.,Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, UMR7590 CNRS/Sorbonne-Université, UPMC, Paris, France
| | - Herman van Tilbeurgh
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS UMR 9198, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif sur Yvette Cedex, France
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