1
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Zatopek KM, Fossa SL, Bilotti K, Caffrey PJ, Chuzel L, Gehring AM, Lohman GJS, Taron CH, Gardner AF. Capillary Electrophoresis-Based Functional Genomics Screening to Discover Novel Archaeal DNA Modifying Enzymes. Appl Environ Microbiol 2022; 88:e0213721. [PMID: 34788065 PMCID: PMC8788744 DOI: 10.1128/aem.02137-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 11/13/2021] [Indexed: 12/05/2022] Open
Abstract
It has been predicted that 30 to 80% of archaeal genomes remain annotated as hypothetical proteins with no assigned gene function. Further, many archaeal organisms are difficult to grow or are unculturable. To overcome these technical and experimental hurdles, we developed a high-throughput functional genomics screen that utilizes capillary electrophoresis (CE) to identify nucleic acid modifying enzymes based on activity rather than sequence homology. Here, we describe a functional genomics screening workflow to find DNA modifying enzyme activities encoded by the hyperthermophile Thermococcus kodakarensis (T. kodakarensis). Large DNA insert fosmid libraries representing an ∼5-fold average coverage of the T. kodakarensis genome were prepared in Escherichia coli. RNA-seq showed a high fraction (84%) of T. kodakarensis genes were transcribed in E. coli despite differences in promoter structure and translational machinery. Our high-throughput screening workflow used fluorescently labeled DNA substrates directly in heat-treated lysates of fosmid clones with capillary electrophoresis detection of reaction products. Using this method, we identified both a new DNA endonuclease activity for a previously described RNA endonuclease (Nob1) and a novel AP lyase DNA repair enzyme family (termed 'TK0353') that is found only in a small subset of Thermococcales. The screening methodology described provides a fast and efficient way to explore the T. kodakarensis genome for a variety of nucleic acid modifying activities and may have implications for similar exploration of enzymes and pathways that underlie core cellular processes in other Archaea. IMPORTANCE This study provides a rapid, simple, high-throughput method to discover novel archaeal nucleic acid modifying enzymes by utilizing a fosmid genomic library, next-generation sequencing, and capillary electrophoresis. The method described here provides the details necessary to create 384-well fosmid library plates from Thermococcus kodakarensis genomic DNA, sequence 384-well fosmids plates using Illumina next-generation sequencing, and perform high-throughput functional read-out assays using capillary electrophoresis to identify a variety of nucleic acid modifying activities, including DNA cleavage and ligation. We used this approach to identify a new DNA endonuclease activity for a previously described RNA endonuclease (Nob1) and identify a novel AP lyase enzyme (TK0353) that lacks sequence homology to known nucleic acid modifying enzymes.
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Affiliation(s)
| | | | | | | | - Léa Chuzel
- New England Biolabs, Inc., Ipswich, Massachusetts, USA
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2
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Saeed MS, Siddiqui MA, Rashid N. Effect of Y50H and S187G substitutions on thermostability and exonuclease activity of TK1646 from Thermococcus kodakarensis. Protein Expr Purif 2020; 179:105799. [PMID: 33249274 DOI: 10.1016/j.pep.2020.105799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/17/2020] [Accepted: 11/20/2020] [Indexed: 10/22/2022]
Abstract
TK1646 is a highly thermostable single strand specific 3'-5' exonuclease. Exonucleases play important role in maintaining the genome integrity at elevated temperatures. Therefore, it is important to examine the factors contributing to thermostability of these exonucleases. In this study we report on production, purification and characterization of S187G and Y50H mutants of TK1646, focusing on the factors leading to thermostability of TK1646. Characterization of the recombinant proteins indicated that these substitutions did not drastically affect the catalysis of single stranded DNA. However, both of these substitutions reduced the thermostability of the recombinant proteins. Half-lives of Y50H and S187G mutants were 95 and 155 min, respectively, at 100 °C in comparison to 180 min of the wild type. Bioinformatics analysis indicated an increase in solvent accessibility of the mutated residues and disruption of hydrogens bonds. Molecular modelling and superimposition of the 3D structures of the mutants and the wild type demonstrated that one of the active site residues, Glu145, was shifted away from the metal ion in both the mutants which may be responsible for the decrease in catalytic activity. Compact secondary structure, hydrophobicity and hydrogen bonding might be the major factors contributing to the thermostability of TK1646.
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Affiliation(s)
| | | | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
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3
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Saeed MS, Rashid N. Characterization of TK1646, a highly thermostable 3'-5' single strand specific exonuclease from Thermococcus kodakarensis. Int J Biol Macromol 2019; 140:1194-1201. [PMID: 31437504 DOI: 10.1016/j.ijbiomac.2019.08.150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/02/2019] [Accepted: 08/17/2019] [Indexed: 10/26/2022]
Abstract
Exonucleases catalyze the hydrolysis of terminal phosphodiester bond in nucleic acid. They play important role in maintaining the integrity of DNA in eukaryotes, prokaryotes and archaea. Limited studies have been done on archaeal exonucleases. Here we report molecular cloning of TK1646, a putative exonuclease from the hyperthermophilic archaeon Thermococcus kodakarensis, and expression of the gene in Escherichia coli. Recombinant TK1646, produced in soluble and active form, was purified to apparent homogeneity. Characterization of the recombinant enzyme indicated that it was single strand specific 3'-5' exonuclease which cleaved the substrate DNA after every two nucleotides. It exhibited highest activity at 85-100 °C and pH 9.0. Unique property of TK1646 was its thermostability as it maintained its activity even at 100 °C with a half-life of 180 min. Recombinant TK1646 followed Michaelis-Menten kinetics and exhibited apparent Km and Vmax values of 33 ± 4 μM and 812 ± 48 nmol/min/mg, respectively. To the best of our knowledge this is the most thermostable single strand specific 3'-5' exonuclease characterized to date.
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Affiliation(s)
| | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan 54590.
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4
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Miyazono KI, Ishino S, Makita N, Ito T, Ishino Y, Tanokura M. Crystal structure of the novel lesion-specific endonuclease PfuEndoQ from Pyrococcus furiosus. Nucleic Acids Res 2019; 46:4807-4818. [PMID: 29660024 PMCID: PMC5961232 DOI: 10.1093/nar/gky261] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/28/2018] [Indexed: 02/03/2023] Open
Abstract
Because base deaminations, which are promoted by high temperature, ionizing radiation, aerobic respiration and nitrosative stress, produce mutations during replication, deaminated bases must be repaired quickly to maintain genome integrity. Recently, we identified a novel lesion-specific endonuclease, PfuEndoQ, from Pyrococcus furiosus, and PfuEndoQ may be involved in the DNA repair pathway in Thermococcales of Archaea. PfuEndoQ recognizes a deaminated base and cleaves the phosphodiester bond 5' of the lesion site. To elucidate the structural basis of the substrate recognition and DNA cleavage mechanisms of PfuEndoQ, we determined the structure of PfuEndoQ using X-ray crystallography. The PfuEndoQ structure and the accompanying biochemical data suggest that PfuEndoQ recognizes a deaminated base using a highly conserved pocket adjacent to a Zn2+-binding site and hydrolyses a phosphodiester bond using two Zn2+ ions. The PfuEndoQ-DNA complex is stabilized by a Zn-binding domain and a C-terminal helical domain, and the complex may recruit downstream proteins in the DNA repair pathway.
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Affiliation(s)
- Ken-Ichi Miyazono
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Sonoko Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, and Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Naruto Makita
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, and Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Tomoko Ito
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, and Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Masaru Tanokura
- Laboratory of Basic Science on Healthy Longevity, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
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5
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Hogrel G, Lu Y, Laurent S, Henry E, Etienne C, Phung DK, Dulermo R, Bossé A, Pluchon PF, Clouet-d'Orval B, Flament D. Physical and functional interplay between PCNA DNA clamp and Mre11-Rad50 complex from the archaeon Pyrococcus furiosus. Nucleic Acids Res 2019; 46:5651-5663. [PMID: 29741662 PMCID: PMC6009593 DOI: 10.1093/nar/gky322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/18/2018] [Indexed: 01/10/2023] Open
Abstract
Several archaeal species prevalent in extreme environments are particularly exposed to factors likely to cause DNA damages. These include hyperthermophilic archaea (HA), living at temperatures >70°C, which arguably have efficient strategies and robust genome guardians to repair DNA damage threatening their genome integrity. In contrast to Eukarya and other archaea, homologous recombination appears to be a vital pathway in HA, and the Mre11–Rad50 complex exerts a broad influence on the initiation of this DNA damage response process. In a previous study, we identified a physical association between the Proliferating Cell Nuclear Antigen (PCNA) and the Mre11–Rad50 (MR) complex. Here, by performing co-immunoprecipitation and SPR analyses, we identified a short motif in the C- terminal portion of Pyrococcus furiosus Mre11 involved in the interaction with PCNA. Through this work, we revealed a PCNA-interaction motif corresponding to a variation on the PIP motif theme which is conserved among Mre11 sequences of Thermococcale species. Additionally, we demonstrated functional interplay in vitro between P. furiosus PCNA and MR enzymatic functions in the DNA end resection process. At physiological ionic strength, PCNA stimulates MR nuclease activities for DNA end resection and promotes an endonucleolytic incision proximal to the 5′ strand of double strand DNA break.
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Affiliation(s)
- Gaëlle Hogrel
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Yang Lu
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Sébastien Laurent
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Etienne Henry
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Clarisse Etienne
- Université de Toulouse; UPS, 118 Route de Narbonne, F-31062 Toulouse, France; CNRS; LMGM; F-31062 Toulouse, France
| | - Duy Khanh Phung
- Université de Toulouse; UPS, 118 Route de Narbonne, F-31062 Toulouse, France; CNRS; LMGM; F-31062 Toulouse, France
| | - Rémi Dulermo
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Audrey Bossé
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Pierre-François Pluchon
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
| | - Béatrice Clouet-d'Orval
- Université de Toulouse; UPS, 118 Route de Narbonne, F-31062 Toulouse, France; CNRS; LMGM; F-31062 Toulouse, France
| | - Didier Flament
- Ifremer, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,Université de Bretagne Occidentale, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France.,CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes, 29280 Plouzané, France
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6
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Possible function of the second RecJ-like protein in stalled replication fork repair by interacting with Hef. Sci Rep 2017; 7:16949. [PMID: 29209094 PMCID: PMC5717133 DOI: 10.1038/s41598-017-17306-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 11/20/2017] [Indexed: 01/03/2023] Open
Abstract
RecJ was originally identified in Escherichia coli and plays an important role in the DNA repair and recombination pathways. Thermococcus kodakarensis, a hyperthermophilic archaeon, has two RecJ-like nucleases. These proteins are designated as GAN (GINS-associated nuclease) and HAN (Hef-associated nuclease), based on the protein they interact with. GAN is probably a counterpart of Cdc45 in the eukaryotic CMG replicative helicase complex. HAN is considered mainly to function with Hef for restoration of the stalled replication fork. In this study, we characterized HAN to clarify its functions in Thermococcus cells. HAN showed single-strand specific 3′ to 5′ exonuclease activity, which was stimulated in the presence of Hef. A gene disruption analysis revealed that HAN was non-essential for viability, but the ΔganΔhan double mutant did not grow under optimal conditions at 85 °C. This deficiency was not fully recovered by introducing the mutant han gene, encoding the nuclease-deficient HAN protein, back into the genome. These results suggest that the unstable replicative helicase complex without GAN performs ineffective fork progression, and thus the stalled fork repair system including HAN becomes more important. The nuclease activity of HAN is required for the function of this protein in T. kodakarensis.
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7
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Kim J, Sambalkhundev GO, Kim S, Son J, Han AR, Ko SM, Hwang KY, Lee WC. Processing of A-form ssDNA by cryptic RNase H fold exonuclease PF2046. Arch Biochem Biophys 2016; 606:143-50. [PMID: 27495739 DOI: 10.1016/j.abb.2016.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/29/2016] [Accepted: 08/01/2016] [Indexed: 11/18/2022]
Abstract
RNase H fold protein PF2046 of Pyrococcus furiosus is a 3'-5' ssDNA exonuclease that cleaves after the second nucleotide from the 3' end of ssDNA and prefers poly-dT over poly-dA as a substrate. In our crystal structure of PF2046 complexed with an oligonucleotide of four thymidine nucleotides (dT4), PF2046 accommodates dT4 tightly in a groove and imposes steric hindrance on dT4 mainly by Phe220 such that dT4 assumes the A-form. As poly-dA prefer B-form due to the stereochemical restrictions, the A-form ssDNA binding by PF2046 should disfavor the processing of poly-dA. Phe220 variants display reduced activity toward poly-dA and the A-form appears to be a prerequisite for the processing by PF2046.
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Affiliation(s)
- Junsoo Kim
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea; Institute for Life Sciences and Natural Resources, Korea University, Seoul 136-713, Republic of Korea
| | - Gerelt-Od Sambalkhundev
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea; Institute for Life Sciences and Natural Resources, Korea University, Seoul 136-713, Republic of Korea
| | - Sulhee Kim
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Jonghyeon Son
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Ah-Reum Han
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Sul-Min Ko
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Kwang Yeon Hwang
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea.
| | - Woo Cheol Lee
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea; Institute for Life Sciences and Natural Resources, Korea University, Seoul 136-713, Republic of Korea.
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8
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Ishino S, Nishi Y, Oda S, Uemori T, Sagara T, Takatsu N, Yamagami T, Shirai T, Ishino Y. Identification of a mismatch-specific endonuclease in hyperthermophilic Archaea. Nucleic Acids Res 2016; 44:2977-86. [PMID: 27001046 PMCID: PMC4838380 DOI: 10.1093/nar/gkw153] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/29/2016] [Indexed: 12/17/2022] Open
Abstract
The common mismatch repair system processed by MutS and MutL and their homologs was identified in Bacteria and Eukarya. However, no evidence of a functional MutS/L homolog has been reported for archaeal organisms, and it is not known whether the mismatch repair system is conserved in Archaea. Here, we describe an endonuclease that cleaves double-stranded DNA containing a mismatched base pair, from the hyperthermophilic archaeon Pyrococcus furiosus The corresponding gene revealed that the activity originates from PF0012, and we named this enzyme Endonuclease MS (EndoMS) as the mismatch-specific Endonuclease. The sequence similarity suggested that EndoMS is the ortholog of NucS isolated from Pyrococcus abyssi, published previously. Biochemical characterizations of the EndoMS homolog from Thermococcus kodakarensis clearly showed that EndoMS specifically cleaves both strands of double-stranded DNA into 5'-protruding forms, with the mismatched base pair in the central position. EndoMS cleaves G/T, G/G, T/T, T/C and A/G mismatches, with a more preference for G/T, G/G and T/T, but has very little or no effect on C/C, A/C and A/A mismatches. The discovery of this endonuclease suggests the existence of a novel mismatch repair process, initiated by the double-strand break generated by the EndoMS endonuclease, in Archaea and some Bacteria.
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Affiliation(s)
- Sonoko Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Fukuoka 812-8581, Japan
| | - Yuki Nishi
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Fukuoka 812-8581, Japan
| | - Soichiro Oda
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Fukuoka 812-8581, Japan
| | - Takashi Uemori
- Takara Bio Inc., Nojihigashi 7-4-38, Kusatsu, Shiga 525-0058, Japan
| | - Takehiro Sagara
- Takara Bio Inc., Nojihigashi 7-4-38, Kusatsu, Shiga 525-0058, Japan
| | - Nariaki Takatsu
- Takara Bio Inc., Nojihigashi 7-4-38, Kusatsu, Shiga 525-0058, Japan
| | - Takeshi Yamagami
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Fukuoka 812-8581, Japan
| | - Tsuyoshi Shirai
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Fukuoka 812-8581, Japan
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9
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Miyazono KI, Ishino S, Tsutsumi K, Ito T, Ishino Y, Tanokura M. Structural basis for substrate recognition and processive cleavage mechanisms of the trimeric exonuclease PhoExo I. Nucleic Acids Res 2015; 43:7122-36. [PMID: 26138487 PMCID: PMC4538837 DOI: 10.1093/nar/gkv654] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/15/2015] [Indexed: 11/30/2022] Open
Abstract
Nucleases play important roles in nucleic acid processes, such as replication, repair and recombination. Recently, we identified a novel single-strand specific 3′-5′ exonuclease, PfuExo I, from the hyperthermophilic archaeon Pyrococcus furiosus, which may be involved in the Thermococcales-specific DNA repair system. PfuExo I forms a trimer and cleaves single-stranded DNA at every two nucleotides. Here, we report the structural basis for the cleavage mechanism of this novel exonuclease family. A structural analysis of PhoExo I, the homologous enzyme from P. horikoshii OT3, showed that PhoExo I utilizes an RNase H-like active site and possesses a 3′-OH recognition site ∼9 Å away from the active site, which enables cleavage at every two nucleotides. Analyses of the heterotrimeric and monomeric PhoExo I activities showed that trimerization is indispensable for its processive cleavage mechanism, but only one active site of the trimer is required.
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Affiliation(s)
- Ken-Ichi Miyazono
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Sonoko Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, and Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Kanae Tsutsumi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Tomoko Ito
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, and Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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10
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Fei L, Tian S, Moysey R, Misca M, Barker JJ, Smith MA, McEwan PA, Pilka ES, Crawley L, Evans T, Sun D. Structural and biochemical studies of a moderately thermophilic exonuclease I from Methylocaldum szegediense. PLoS One 2015; 10:e0117470. [PMID: 25658953 PMCID: PMC4319927 DOI: 10.1371/journal.pone.0117470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/25/2014] [Indexed: 11/18/2022] Open
Abstract
A novel exonuclease, designated as MszExo I, was cloned from Methylocaldum szegediense, a moderately thermophilic methanotroph. It specifically digests single-stranded DNA in the 3ʹ to 5ʹ direction. The protein is composed of 479 amino acids, and it shares 47% sequence identity with E. coli Exo I. The crystal structure of MszExo I was determined to a resolution of 2.2 Å and it aligns well with that of E. coli Exo I. Comparative studies revealed that MszExo I and E. coli Exo I have similar metal ion binding affinity and similar activity at mesophilic temperatures (25–47°C). However, the optimum working temperature of MszExo I is 10°C higher, and the melting temperature is more than 4°C higher as evaluated by both thermal inactivation assays and DSC measurements. More importantly, two thermal transitions during unfolding of MszExo I were monitored by DSC while only one transition was found in E. coli Exo I. Further analyses showed that magnesium ions not only confer structural stability, but also affect the unfolding of MszExo I. MszExo I is the first reported enzyme in the DNA repair systems of moderately thermophilic bacteria, which are predicted to have more efficient DNA repair systems than mesophilic ones.
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Affiliation(s)
- Li Fei
- New England Biolabs Shanghai R&D Center, Building 5, 917 Halei Road, Pudong District, Shanghai, China
| | - SiSi Tian
- New England Biolabs Shanghai R&D Center, Building 5, 917 Halei Road, Pudong District, Shanghai, China
| | - Ruth Moysey
- Oxford Nanopore Technologies Ltd., Edmund Cartwright House, 4 Robert Robinson Avenue Oxford Science Park, Oxford OX4, United Kingdom
| | - Mihaela Misca
- Oxford Nanopore Technologies Ltd., Edmund Cartwright House, 4 Robert Robinson Avenue Oxford Science Park, Oxford OX4, United Kingdom
| | - John J. Barker
- Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Myron A. Smith
- Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Paul A. McEwan
- Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Ewa S. Pilka
- Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Lauren Crawley
- Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Tom Evans
- New England Biolabs, 240 County Road, Ipswich, MA 01938–2723, United States of America
| | - Dapeng Sun
- New England Biolabs Shanghai R&D Center, Building 5, 917 Halei Road, Pudong District, Shanghai, China
- * E-mail:
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Miyazono KI, Tsutsumi K, Ishino Y, Tanokura M. Expression, high-pressure refolding, purification, crystallization and preliminary X-ray analysis of a novel single-strand-specific 3'-5' exonuclease PhoExo I from Pyrococcus horikoshii OT3. Acta Crystallogr F Struct Biol Commun 2014; 70:1076-9. [PMID: 25084386 PMCID: PMC4118808 DOI: 10.1107/s2053230x14012734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 06/01/2014] [Indexed: 12/22/2022] Open
Abstract
PhoExo I is a single-strand-specific 3'-5' exonuclease from Pyrococcus horikoshii OT3 and is thought to be involved in a Thermococcales-specific DNA-repair pathway. The recombinant PhoExo I protein was produced as inclusion bodies in Escherichia coli cells. Solubilization of the inclusion bodies was performed by the high-pressure refolding method and highly purified protein was subjected to crystallization by the sitting-drop vapour-diffusion method at 20°C. A crystal of PhoExo I was obtained in a reservoir solution consisting of 0.1 M Tris-HCl pH 8.9, 27% PEG 6000 and diffracted X-rays to 1.52 Å resolution. The crystal of PhoExo I belonged to space group H32, with unit-cell parameters a = b = 112.07, c = 202.28 Å. The crystal contained two PhoExo I molecules in the asymmetric unit.
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Affiliation(s)
- Ken-ichi Miyazono
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kanae Tsutsumi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yoshizumi Ishino
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, and Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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