1
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Kitagawa Y, Liao Z, Morikawa K, Oda M. Metal-binding and folding thermodynamics of Escherichia coli ribonuclease HI related to its catalytic function. Biophys Chem 2023; 295:106961. [PMID: 36736006 DOI: 10.1016/j.bpc.2023.106961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/30/2023]
Abstract
Escherichia coli ribonuclease HI (RNH) hydrolyzes the RNA strands of RNA/DNA hybrids in the presence of Mg2+ at the highest level, relative to other metal ions. The Mg2+ binding affinity was 8.39 × 103 M-1, which was lower than those of other metal ions. The low-affinity binder can express the maximum catalytic activity of RNH. The stability of RNH increased with increasing metal ion concentration, except for Zn2+. The thermodynamic origin for enhancing the stability of RNH with Mg2+ was more favorable entropy compared to those with other metal ions, indicating that Mg2+ binding changes the RNH structure while maintaining flexibility. Upon H124A mutation, the metal ion binding affinities decreased for Mn2+ and Zn2+ to a relatively large extent. The present thermodynamic analyses provide information on the structural dynamics of RNH with metal ion exchangeable binding, which can reasonably explain the metal-ion-dependent catalytic activity.
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Affiliation(s)
- Yumi Kitagawa
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamo Hangi-cho, Sakyo-ku, Kyoto, Kyoto 606-8522, Japan
| | - Zengwei Liao
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamo Hangi-cho, Sakyo-ku, Kyoto, Kyoto 606-8522, Japan; Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kosuke Morikawa
- Graduate School of Biostudies, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto, Kyoto 606-8501, Japan
| | - Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamo Hangi-cho, Sakyo-ku, Kyoto, Kyoto 606-8522, Japan.
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2
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Pang J, Guo Q, Lu Z. The catalytic mechanism, metal dependence, substrate specificity, and biodiversity of ribonuclease H. Front Microbiol 2022; 13:1034811. [PMID: 36478866 PMCID: PMC9719913 DOI: 10.3389/fmicb.2022.1034811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/31/2022] [Indexed: 11/29/2023] Open
Abstract
Ribonucleoside monophosphates are inevitably misincorporated into the DNA genome inside cells, and they need to be excised to avoid chromosome instability. Ribonucleases H (RNases H) are enzymes that specifically hydrolyze the RNA strand of RNA/DNA hybrids or the RNA moiety from DNA containing a stretch of RNA, they therefore are required for DNA integrity. Extensive studies have drawn a mostly clear picture of the mechanisms of RNase H catalysis, but some questions are still lacking definitive answers. This review summarizes three alternative models of RNase H catalysis. The two-metal model is prevalent, but a three-metal model suggests the involvement of a third cation in catalysis. Apparently, the mechanisms underlying metal-dependent hydrolyzation are more complicated than initially thought. We also discuss the metal choices of RNases H and analyze how chemically similar cations function differently. Substrate and cleavage-site specificities vary among RNases H, and this is explicated in detail. An intriguing phenomenon is that organisms have diverse RNase H combinations, which may provide important hints to how rnh genes were transferred during evolution. Whether RNase H is essential for cellular growth, a key question in the study of in vivo functions, is also discussed. This article may aid in understanding the mechanisms underlying RNase H and in developing potentially promising applications of it.
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Affiliation(s)
| | | | - Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, China
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3
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Ando T, Jongruja N, Okumura N, Morikawa K, Kanaya S, Takao T. Identification of the ternary complex of ribonuclease HI:RNA/DNA hybrid:metal ions by ESI mass spectrometry. J Biol Chem 2021; 296:100462. [PMID: 33639158 PMCID: PMC8042393 DOI: 10.1016/j.jbc.2021.100462] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/14/2021] [Accepted: 02/23/2021] [Indexed: 12/17/2022] Open
Abstract
Ribonuclease HI, an endoribonuclease, catalyzes the hydrolysis of the RNA strand of an RNA/DNA hybrid and requires divalent metal ions for its enzymatic activity. However, the mechanistic details of the activity of ribonuclease HI and its interaction with divalent metal ions remain unclear. In this study, we performed real-time monitoring of the enzyme–substrate complex in the presence of divalent metal ions (Mn2+ or Zn2+) using electrospray ionization–mass spectrometry (ESI-MS). The findings provide clear evidence that the enzymatic activity of the ternary complex requires the binding of two divalent metal ions. The Zn2+ ions bind to both the enzyme itself and the enzyme:substrate complex more strongly than Mn2+ ions, and gives, in part, the ternary complex, [RNase HI:nicked RNA/DNA hybrid:2Zn2+], suggesting that the ternary complex is retained, even after the hydrolysis of the substrate. The collective results presented herein shed new light on the essential role of divalent metal ions in the activity of ribonuclease HI and demonstrate how Zn2+ ions confer inhibitory properties on the activity of this enzyme by forming a highly stable complex with the substrate.
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Affiliation(s)
- Tomoshige Ando
- Institute for Protein Research, Osaka University, Osaka, Japan
| | | | - Nobuaki Okumura
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Kosuke Morikawa
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | | | - Toshifumi Takao
- Institute for Protein Research, Osaka University, Osaka, Japan.
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4
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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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5
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Stafford KA, Trbovic N, Butterwick JA, Abel R, Friesner RA, Palmer AG. Conformational preferences underlying reduced activity of a thermophilic ribonuclease H. J Mol Biol 2014; 427:853-866. [PMID: 25550198 DOI: 10.1016/j.jmb.2014.11.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/14/2014] [Indexed: 11/30/2022]
Abstract
The conformational basis for reduced activity of the thermophilic ribonuclease HI enzyme from Thermus thermophilus, compared to its mesophilic homolog from Escherichia coli, is elucidated using a combination of NMR spectroscopy and molecular dynamics (MD) simulations. Explicit-solvent all-atom MD simulations of the two wild-type proteins and an E. coli mutant in which a glycine residue is inserted after position 80 to mimic the T. thermophilus protein reproduce the differences in conformational dynamics determined from (15)N spin-relaxation NMR spectroscopy of three loop regions that surround the active site and contain functionally important residues: the glycine-rich region, the handle region, and the β5/αE loop. Examination of the MD trajectories indicates that the thermophilic protein samples conformations productive for substrate binding and activity less frequently than the mesophilic enzyme, although these differences may manifest as either increased or decreased relative flexibility of the different regions. Additional MD simulations indicate that mutations increasing activity of the T. thermophilus enzyme at mesophilic temperatures do so by reconfiguring the local environments of the mutated sites to more closely resemble active conformations. Taken together, the results show that both locally increased and decreased flexibility contribute to an overall reduction in activity of T. thermophilus ribonuclease H compared to its mesophilic E. coli homolog.
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Affiliation(s)
- Kate A Stafford
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Nikola Trbovic
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Joel A Butterwick
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Robert Abel
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | | | - Arthur G Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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6
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Divalent metal ion-induced folding mechanism of RNase H1 from extreme halophilic archaeon Halobacterium sp. NRC-1. PLoS One 2014; 9:e109016. [PMID: 25268753 PMCID: PMC4182655 DOI: 10.1371/journal.pone.0109016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 08/28/2014] [Indexed: 01/23/2023] Open
Abstract
RNase H1 from Halobacterium sp. NRC-1 (Halo-RNase H1) is characterized by the abundance of acidic residues on the surface, including bi/quad-aspartate site residues. Halo-RNase H1 exists in partially folded (I) and native (N) states in low-salt and high-salt conditions respectively. Its folding is also induced by divalent metal ions. To understand this unique folding mechanism of Halo-RNase H1, the active site mutant (2A-RNase H1), the bi/quad-aspartate site mutant (6A-RNase H1), and the mutant at both sites (8A-RNase H1) were constructed. The far-UV CD spectra of these mutants suggest that 2A-RNase H1 mainly exists in the I state, 6A-RNase H1 exists both in the I and N states, and 8A-RNase H1 mainly exists in the N state in a low salt-condition. These results suggest that folding of Halo-RNase H1 is induced by binding of divalent metal ions to the bi/quad-aspartate site. To examine whether metal-induced folding is unique to Halo-RNase H1, RNase H2 from the same organism (Halo-RNase H2) was overproduced and purified. Halo-RNase H2 exists in the I and N states in low-salt and high-salt conditions respectively, as does Halo-RNase H1. However, this protein exists in the I state even in the presence of divalent metal ions. Halo-RNase H2 exhibits junction ribonuclease activity only in a high-salt condition. A tertiary model of this protein suggests that this protein does not have a quad-aspartate site. We propose that folding of Halo-RNase H1 is induced by binding of divalent metal ion to the quad-aspartate site in a low-salt condition.
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7
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Stafford KA, Palmer Iii AG. Evidence from molecular dynamics simulations of conformational preorganization in the ribonuclease H active site. F1000Res 2014; 3:67. [PMID: 25075292 PMCID: PMC4032109 DOI: 10.12688/f1000research.3605.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/07/2014] [Indexed: 11/26/2022] Open
Abstract
Ribonuclease H1 (RNase H) enzymes are well-conserved endonucleases that are present in all domains of life and are particularly important in the life cycle of retroviruses as domains within reverse transcriptase. Despite extensive study, especially of the E. coli homolog, the interaction of the highly negatively charged active site with catalytically required magnesium ions remains poorly understood. In this work, we describe molecular dynamics simulations of the E. coli homolog in complex with magnesium ions, as well as simulations of other homologs in their apo states. Collectively, these results suggest that the active site is highly rigid in the apo state of all homologs studied and is conformationally preorganized to favor the binding of a magnesium ion. Notably, representatives of bacterial, eukaryotic, and retroviral RNases H all exhibit similar active-site rigidity, suggesting that this dynamic feature is only subtly modulated by amino acid sequence and is primarily imposed by the distinctive RNase H protein fold.
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Affiliation(s)
- Kate A Stafford
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Arthur G Palmer Iii
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
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8
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Stafford KA, Ferrage F, Cho JH, Palmer AG. Side chain dynamics of carboxyl and carbonyl groups in the catalytic function of Escherichia coli ribonuclease H. J Am Chem Soc 2013; 135:18024-7. [PMID: 24219366 DOI: 10.1021/ja409479y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many proteins use Asx and Glx (x = n, p, or u) side chains as key functional groups in enzymatic catalysis and molecular recognition. In this study, NMR spin relaxation experiments and molecular dynamics simulations are used to measure the dynamics of the side chain amide and carboxyl groups, (13)C(γ/δ), in Escherichia coli ribonuclease HI (RNase H). Model-free analysis shows that the catalytic residues in RNase H are preorganized on ps-ns time scales via a network of electrostatic interactions. However, chemical exchange line broadening shows that these residues display significant conformational dynamics on μs-ms time scales upon binding of Mg(2+) ions. Two groups of catalytic residues exhibit differential line broadening, implicating distinct reorganizational processes upon binding of metal ions. These results support the "mobile metal ion" hypothesis, which was inferred from structural studies of RNase H.
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Affiliation(s)
- Kate A Stafford
- Department of Biochemistry and Molecular Biophysics, Columbia University , New York, New York 10032, United States
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9
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Viral enzymes containing magnesium: Metal binding as a successful strategy in drug design. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.07.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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10
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Tannous E, Yokoyama K, You DJ, Koga Y, Kanaya S. A dual role of divalent metal ions in catalysis and folding of RNase H1 from extreme halophilic archaeon Halobacterium sp. NRC-1. FEBS Open Bio 2012; 2:345-52. [PMID: 23772368 PMCID: PMC3678122 DOI: 10.1016/j.fob.2012.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 10/19/2012] [Accepted: 10/19/2012] [Indexed: 11/03/2022] Open
Abstract
RNase H1 from extreme halophilic archaeon Halobacterium sp. NRC-1 (Halo-RNH1) consists of an N-terminal domain with unknown function and a C-terminal RNase H domain. It is characterized by the high content of acidic residues on the protein surface. The far- and near-UV CD spectra of Halo-RNH1 suggested that Halo-RNH1 assumes a partially folded structure in the absence of salt and divalent metal ions. It requires either salt or divalent metal ions for folding. However, thermal denaturation of Halo-RNH1 analyzed in the presence of salt and/or divalent metal ions by CD spectroscopy suggested that salt and divalent metal ions independently stabilize the protein and thereby facilitate folding. Divalent metal ions stabilize the protein probably by binding mainly to the active site and suppressing negative charge repulsions at this site. Salt stabilizes the protein probably by increasing hydrophobic interactions at the protein core and decreasing negative charge repulsions on the protein surface. Halo-RNH1 exhibited activity in the presence of divalent metal ions regardless of the presence or absence of 3 M NaCl. However, higher concentrations of divalent metal ions are required for activity in the absence of salt to facilitate folding. Thus, divalent metal ions play a dual role in catalysis and folding of Halo-RNH1. Construction of the Halo-RNH1 derivatives lacking an N- or C-terminal domain, followed by biochemical characterizations, indicated that an N-terminal domain is dispensable for stability, activity, folding, and substrate binding of Halo-RNH1.
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Affiliation(s)
- Elias Tannous
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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11
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Ho MH, De Vivo M, Dal Peraro M, Klein ML. Understanding the effect of magnesium ion concentration on the catalytic activity of ribonuclease H through computation: does a third metal binding site modulate endonuclease catalysis? J Am Chem Soc 2011; 132:13702-12. [PMID: 20731347 DOI: 10.1021/ja102933y] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ribonuclease H (RNase H) belongs to the nucleotidyl-transferase superfamily and hydrolyzes the phosphodiester linkage on the RNA strand of a DNA/RNA hybrid duplex. Due to its activity in HIV reverse transcription, it represents a promising target for anti-HIV drug design. While crystallographic data have located two ions in the catalytic site, there is ongoing debate concerning just how many metal ions bound at the active site are optimal for catalysis. Indeed, experiments have shown a dependency of the catalytic activity on the Mg(2+) concentration. Moreover, in RNase H, the glutamate residue E188 has been shown to be essential for full enzymatic activation, regardless of the Mg(2+) concentration. The catalytic center is known to contain two Mg(2+) ions, and E188 is not one of the primary metal ligands. Herein, classical molecular dynamics (MD) simulations are employed to study the metal-ligand coordination in RNase H at different concentration of Mg(2+). Importantly, the presence of a third Mg(2+) ion, bound to the second-shell ligand E188, is a persistent feature of the MD simulations. Free energy calculations have identified two distinct conformations, depending on the concentration of Mg(2+). At standard concentration, a third Mg(2+) is found in the catalytic pocket, but it does not perturb the optimal RNase H active conformation. However, at higher concentration, the third Mg(2+) ion heavily perturbs the nucleophilic water and thereby influences the catalytic efficiency of RNase H. In addition, the E188A mutant shows no ability to engage additional Mg(2+) ions near the catalytic pocket. This finding likely explains the decrease in catalytic activity of E188A and also supports the key role of E188 in localizing the third Mg(2+) ion at the active site. Glutamate residues are commonly found surrounding the metal center in the endonuclease family, which suggests that this structural motif may be an important feature to enhance catalytic activity. The present MD calculations support the hypothesis that RNase H can accommodate three divalent metal ions in its catalytic pocket and provide an in-depth understanding of their dynamic role for catalysis.
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Affiliation(s)
- Ming-Hsun Ho
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania, 19104, USA
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12
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Prymula K, Jadczyk T, Roterman I. Catalytic residues in hydrolases: analysis of methods designed for ligand-binding site prediction. J Comput Aided Mol Des 2010; 25:117-33. [PMID: 21104192 PMCID: PMC3032897 DOI: 10.1007/s10822-010-9402-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 11/08/2010] [Indexed: 11/26/2022]
Abstract
The comparison of eight tools applicable to ligand-binding site prediction is presented. The methods examined cover three types of approaches: the geometrical (CASTp, PASS, Pocket-Finder), the physicochemical (Q-SiteFinder, FOD) and the knowledge-based (ConSurf, SuMo, WebFEATURE). The accuracy of predictions was measured in reference to the catalytic residues documented in the Catalytic Site Atlas. The test was performed on a set comprising selected chains of hydrolases. The results were analysed with regard to size, polarity, secondary structure, accessible solvent area of predicted sites as well as parameters commonly used in machine learning (F-measure, MCC). The relative accuracies of predictions are presented in the ROC space, allowing determination of the optimal methods by means of the ROC convex hull. Additionally the minimum expected cost analysis was performed. Both advantages and disadvantages of the eight methods are presented. Characterization of protein chains in respect to the level of difficulty in the active site prediction is introduced. The main reasons for failures are discussed. Overall, the best performance offers SuMo followed by FOD, while Pocket-Finder is the best method among the geometrical approaches.
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Affiliation(s)
- Katarzyna Prymula
- Faculty of Chemistry, Jagiellonian University, 3 Ingardena Street, 30-060 Krakow, Poland
- Department of Bioinformatics and Telemedicine, Medical College, Jagiellonian University, 7E Kopernika Street, 31-034 Krakow, Poland
| | - Tomasz Jadczyk
- Department of Electronics, AGH University of Science and Technology, 30 Mickiewicza Avenue, 30-059 Krakow, Poland
| | - Irena Roterman
- Department of Bioinformatics and Telemedicine, Medical College, Jagiellonian University, 16 Lazarza Street, 31-530 Krakow, Poland
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13
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HIV-1 Ribonuclease H: Structure, Catalytic Mechanism and Inhibitors. Viruses 2010; 2:900-926. [PMID: 21994660 PMCID: PMC3185654 DOI: 10.3390/v2040900] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/22/2010] [Accepted: 03/24/2010] [Indexed: 11/16/2022] Open
Abstract
Since the human immunodeficiency virus (HIV) was discovered as the etiological agent of acquired immunodeficiency syndrome (AIDS), it has encouraged much research into antiviral compounds. The reverse transcriptase (RT) of HIV has been a main target for antiviral drugs. However, all drugs developed so far inhibit the polymerase function of the enzyme, while none of the approved antiviral agents inhibit specifically the necessary ribonuclease H (RNase H) function of RT. This review provides a background on structure-function relationships of HIV-1 RNase H, as well as an outline of current attempts to develop novel, potent chemotherapeutics against a difficult drug target.
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14
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Pingoud V, Wende W, Friedhoff P, Reuter M, Alves J, Jeltsch A, Mones L, Fuxreiter M, Pingoud A. On the divalent metal ion dependence of DNA cleavage by restriction endonucleases of the EcoRI family. J Mol Biol 2009; 393:140-60. [PMID: 19682999 DOI: 10.1016/j.jmb.2009.08.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 08/05/2009] [Accepted: 08/06/2009] [Indexed: 11/18/2022]
Abstract
Restriction endonucleases of the PD...D/EXK family need Mg(2+) for DNA cleavage. Whereas Mg(2+) (or Mn(2+)) promotes catalysis, Ca(2+) (without Mg(2+)) only supports DNA binding. The role of Mg(2+) in DNA cleavage by restriction endonucleases has elicited many hypotheses, differing mainly in the number of Mg(2+) involved in catalysis. To address this problem, we measured the Mg(2+) and Mn(2+) concentration dependence of DNA cleavage by BamHI, BglII, Cfr10I, EcoRI, EcoRII (catalytic domain), MboI, NgoMIV, PspGI, and SsoII, which were reported in co-crystal structure analyses to bind one (BglII and EcoRI) or two (BamHI and NgoMIV) Me(2+) per active site. DNA cleavage experiments were carried out at various Mg(2+) and Mn(2+) concentrations at constant ionic strength. All enzymes show a qualitatively similar Mg(2+) and Mn(2+) concentration dependence. In general, the Mg(2+) concentration optimum (between approximately 1 and 10 mM) is higher than the Mn(2+) concentration optimum (between approximately 0.1 and 1 mM). At still higher Mg(2+) or Mn(2+) concentrations, the activities of all enzymes tested are reduced but can be reactivated by Ca(2+). Based on these results, we propose that one Mg(2+) or Mn(2+) is critical for restriction enzyme activation, and binding of a second Me(2+) plays a role in modulating the activity. Steady-state kinetics carried out with EcoRI and BamHI suggest that binding of a second Mg(2+) or Mn(2+) mainly leads to an increase in K(m), such that the inhibitory effect of excess Mg(2+) or Mn(2+) can be overcome by increasing the substrate concentration. Our conclusions are supported by molecular dynamics simulations and are consistent with the structural observations of both one and two Me(2+) binding to these enzymes.
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Affiliation(s)
- Vera Pingoud
- Institut für Biochemie, Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.
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15
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Tadokoro T, Kanaya S. Ribonuclease H: molecular diversities, substrate binding domains, and catalytic mechanism of the prokaryotic enzymes. FEBS J 2009; 276:1482-93. [PMID: 19228197 DOI: 10.1111/j.1742-4658.2009.06907.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The prokaryotic genomes, for which complete nucleotide sequences are available, always contain at least one RNase H gene, indicating that RNase H is ubiquitous in all prokaryotic cells. Coupled with its unique substrate specificity, the enzyme has been expected to play crucial roles in the biochemical processes associated with DNA replication, gene expression and DNA repair. The physiological role of prokaryotic RNases H, especially of type 1 RNases H, has been extensively studied using Escherichia coli strains that are defective in RNase HI activity or overproduce RNase HI. However, it is not fully understood yet. By contrast, significant progress has been made in this decade in identifying novel RNases H with respect to their biochemical properties and structures, and elucidating catalytic mechanism and substrate recognition mechanism of RNase H. We review the results of these studies.
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Affiliation(s)
- Takashi Tadokoro
- Department of Material and Life Science, Osaka University, Suita, Osaka, Japan
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16
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Lu M, Wang H, Wang Z, Li XF, Le XC. Identification of reactive cysteines in a protein using arsenic labeling and collision-induced dissociation tandem mass spectrometry. J Proteome Res 2008; 7:3080-90. [PMID: 18613716 DOI: 10.1021/pr700662y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trivalent arsenicals have high affinity for thiols (such as free cysteines) in proteins. We describe here the use of this property to develop a collision-induced dissociation (CID) tandem mass spectrometry (MS/MS) technique for the identification of reactive cysteines in proteins. A trivalent arsenic species, dimethylarsinous acid (DMA (III)), with a residue mass (103.9607) and mass defect distinct from the normal 20 amino acids, was used to selectively label reactive cysteine residues in proteins. The CID fragment ions of the arsenic-labeled sequences shifted away from the more abundant normal fragments that would otherwise overlap with the ions of interest. Along with the internal and immonium ions, the arsenic-labeled fragment ions served as MS/MS signatures for identification of the binding sites and for assessment of the relative reactivity of individual cysteine residues in a protein. Using this method, we have identified two highly reactive binding sites in rat hemoglobin (Hb): Cys-13alpha and Cys-125beta. Cys-13alpha was bound to DMA (III) in the Hb of rats fed with arsenic, and this binding was responsible for arsenic accumulation in rat blood, while Cys-125beta was found to bind to glutathione in rat blood. This study revealed the relative reactivity of the cysteines in rat Hb in the following decreasing order: Cys-13alpha >> Cys-111alpha > Cys-104alpha and Cys-13alpha >> Cys-125beta > Cys-93beta. Arsenic-labeling is easy and fast for identification of active binding sites without enzymatic digestion and acid hydrolysis, and useful for characterization and identification of metal binding sites in other proteins.
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Affiliation(s)
- Meiling Lu
- Department of Chemistry and Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
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17
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Dupureur CM. Roles of metal ions in nucleases. Curr Opin Chem Biol 2008; 12:250-5. [PMID: 18261473 DOI: 10.1016/j.cbpa.2008.01.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 01/09/2008] [Indexed: 10/22/2022]
Abstract
The hydrolysis of phosphodiester bonds by metallonucleases is crucial to most aspects of nucleic acid processing. In recent years, studies of the classical restriction endonucleases have given way to the characterization of metallonucleases with widely divergent active site motifs. These developments fuel debates regarding the roles of metal ions in these enzymes. It is fortuitous that the current literature also includes the increased application of a variety of computational techniques to test the roles of metal ions in nucleic acid hydrolysis by these systems. This includes recent proposals and indirect evidence that these enzymes utilize metal ion movement in these reactions.
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Affiliation(s)
- Cynthia M Dupureur
- Department of Chemistry & Biochemistry and the Center for Nanoscience, University of Missouri-St. Louis, MC 27, One University Boulevard, St. Louis, MO 63121, United States.
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18
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Coté ML, Roth MJ. Murine leukemia virus reverse transcriptase: structural comparison with HIV-1 reverse transcriptase. Virus Res 2008; 134:186-202. [PMID: 18294720 DOI: 10.1016/j.virusres.2008.01.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Revised: 12/31/2007] [Accepted: 01/02/2008] [Indexed: 10/22/2022]
Abstract
Recent X-ray crystal structure determinations of Moloney murine leukemia virus reverse transcriptase (MoMLV RT) have allowed for more accurate structure/function comparisons to HIV-1 RT than were formerly possible. Previous biochemical studies of MoMLV RT in conjunction with knowledge of sequence homologies to HIV-1 RT and overall fold similarities to RTs in general, provided a foundation upon which to build. In addition, numerous crystal structures of the MoMLV RT fingers/palm subdomain had also shed light on one of the critical functions of the enzyme, specifically polymerization. Now in the advent of new structural information, more intricate examination of MoMLV RT in its entirety can be realized, and thus the comparisons with HIV-1 RT may be more critically elucidated. Here, we will review the similarities and differences between MoMLV RT and HIV-1 RT via structural analysis, and propose working models for the MoMLV RT based upon that information.
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Affiliation(s)
- Marie L Coté
- Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, United States
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19
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Tang L, Liu H. A comparative molecular dynamics study of thermophilic and mesophilic ribonuclease HI enzymes. J Biomol Struct Dyn 2007; 24:379-92. [PMID: 17206853 DOI: 10.1080/07391102.2007.10507127] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
We studied a pair of homologous thermophilic and mesophilic ribonuclease HI enzymes by molecular dynamics simulations. Each protein was subjected to three 5 ns simulations in explicit water at both 310 K and 340 K. The thermophilic enzyme showed larger overall positional fluctuations at both temperatures, while only the mesophilic enzyme at the higher temperature showed significant instability. When the temperature is changed, the relative flexibility of different local segments on the two proteins changed differently. Principal component analysis showed that the simulations of the two proteins explored largely overlapping regions in the conformational space. However, at 340 K, the collective structure variations of the thermophilic protein are different from those of the mesophilic protein. Our results, although not in accordance with the view that hyperthermostability of proteins may originate from their conformational rigidity, are consistent with several recent experimental and simulation studies which showed that thermophilic proteins may be conformationally more flexible than their mesophilic counterparts. The decorrelation between conformational rigidity and hyperthermostability may be attributed to the temperature dependence and long range nature of electrostatic interactions that play more important roles in the structural stability of thermophilic proteins.
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Affiliation(s)
- Ling Tang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China (USTC), Hefei, Anhui 230027, P. R. China
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20
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Bastock JA, Webb M, Grasby JA. The pH-dependence of the Escherichia coli RNase HII-catalysed reaction suggests that an active site carboxylate group participates directly in catalysis. J Mol Biol 2007; 368:421-33. [PMID: 17355881 DOI: 10.1016/j.jmb.2007.01.083] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 01/24/2007] [Accepted: 01/31/2007] [Indexed: 11/15/2022]
Abstract
RNase HII specifically catalyses the hydrolysis of phosphate diester linkages contained within the RNA portion of DNA/RNA hybrids. The catalytic parameters of the enzyme derived from Escherichia coli BL21 have been measured using 5'-fluorescent oligodeoxynucleotide substrates containing embedded ribonucleotides. The products of the reaction and the chemistry of phosphate diester hydrolysis were assigned unequivocally using mass spectrometry. The pH-dependence of the catalytic parameters was measured under conditions of optimal magnesium ion concentration. The logarithm of the turnover number of the enzyme increases steeply with pH until a pH-independent region is reached close to neutrality. The slope of the pH-dependent region is 2, indicating that the catalytically proficient form of RNase HII is di-anionic. The pH-dependence of log 1/K(M) is a sigmoidal curve reaching a maximal value at higher pH, suggesting deprotonation of a residue stabilises substrate binding. Possible mechanisms for the RNase HII-catalysed reaction consistent with the pH-dependent behaviour of the enzyme are discussed. The active sites of RNase H enzymes contain a cluster of four strictly conserved carboxylate groups. Together, the data suggest a requirement for ionisation of an active site carboxylic acid for metal ion binding or correct positioning of metal ion(s) in the enzyme-substrate complex and a role for a second active site carboxylate in general base catalysis.
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Affiliation(s)
- James A Bastock
- Centre for Chemical Biology, Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK
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21
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Mukaiyama A, Haruki M, Ota M, Koga Y, Takano K, Kanaya S. A hyperthermophilic protein acquires function at the cost of stability. Biochemistry 2006; 45:12673-9. [PMID: 17042484 DOI: 10.1021/bi060907v] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Active-site residues are not often optimized for conformational stability (activity-stability trade-offs) in proteins from organisms that grow at moderate temperature. It is unknown if the activity-stability trade-offs can be applied to proteins from hyperthermophiles. Because enzymatic activity usually increases at higher temperature and hyperthermophilic proteins need high conformational stability, they might not sacrifice the stability for their activity. This study attempts to clarify the contribution of active-site residues to the conformational stability of a hyperthermophilic protein. We therefore examined the thermodynamic stability and enzymatic activity of wild-type and active-site mutant proteins (D7N, E8A, E8Q, D105A, and D135A) of ribonuclease HII from Thermococcus kodakaraensis (Tk-RNase HII). Guanidine hydrochloride (GdnHCl)-induced denaturation was measured with circular dichroism at 220 nm, and heat-induced denaturation was studied with differential scanning calorimetry. Both GdnHCl- and heat-induced denaturation were highly reversible in these proteins. All the mutations of these active-site residues, except that of Glu8 to Gln, reduced the enzymatic activity dramatically but increased the protein stability by 7.0 to 11.1 kJ mol(-1) at 50 degrees C. The mutation of Glu8 to Gln did not seriously affect the enzymatic activity and increased the stability only by 2.5 kJ mol(-1) at 50 degrees C. These results indicate that hyperthermophilic proteins also exhibit the activity-stability trade-offs. Therefore, the architectural mechanism for hyperthermophilic proteins is equivalent to that for proteins at normal temperature.
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Affiliation(s)
- Atsushi Mukaiyama
- Department of Material and Life Science, Osaka University, Yamadaoka, Suita 565-0871, Japan
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22
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Diamond TL, Bushman FD. Role of metal ions in catalysis by HIV integrase analyzed using a quantitative PCR disintegration assay. Nucleic Acids Res 2006; 34:6116-25. [PMID: 17085478 PMCID: PMC1693899 DOI: 10.1093/nar/gkl862] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Paired metal ions have been proposed to be central to the catalytic mechanisms of RNase H nucleases, bacterial transposases, Holliday junction resolvases, retroviral integrases and many other enzymes. Here we present a sensitive assay for DNA transesterification in which catalysis by human immunodeficiency virus-type 1 (HIV-1) integrase (IN) connects two DNA strands (disintegration reaction), allowing detection using quantitative PCR (qPCR). We present evidence suggesting that the three acidic residues of the IN active site function through metal binding using metal rescue. In this method, the catalytic acidic residues were each substituted with cysteines. Mn2+ binds tightly to the sulfur atoms of the cysteine residues, but Mg2+ does not. We found that Mn2+, but not Mg2+, could rescue catalysis of each cysteine-substituted enzyme, providing evidence for functionally important metal binding by all three residues. We also used the PCR-boosted assay to show that HIV-1 IN could carry out transesterification reactions involving DNA 5' hydroxyl groups as well as 3' hydroxyls as nucleophiles. Lastly, we show that Mn2+ by itself (i.e. without enzyme) can catalyze formation of a low level of PCR-amplifiable product under extreme conditions, allowing us to estimate the rate enhancement due to the IN-protein scaffold as at least 60 million-fold.
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Affiliation(s)
| | - Frederic D. Bushman
- To whom correspondence should be addressed. Tel: +1 215 573 8732; Fax: +1 215 573 4856;
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23
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You DJ, Chon H, Koga Y, Takano K, Kanaya S. Crystallization and preliminary crystallographic analysis of type 1 RNase H from the hyperthermophilic archaeon Sulfolobus tokodaii 7. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:781-4. [PMID: 16880556 PMCID: PMC2242919 DOI: 10.1107/s1744309106024420] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Accepted: 06/26/2006] [Indexed: 11/11/2022]
Abstract
Crystallization and preliminary crystallographic studies of type 1 RNase H from the hyperthermophilic archaeon Sulfolobus tokodaii 7 were performed. A crystal was grown at 277 K by the sitting-drop vapour-diffusion method. Native X-ray diffraction data were collected to 1.5 angstroms resolution using synchrotron radiation from station BL41XU at SPring-8. The crystal belongs to space group P4(3), with unit-cell parameters a = b = 39.21, c = 91.15 angstroms. Assuming the presence of one molecule in the asymmetric unit, the Matthews coefficient V(M) was calculated to be 2.1 angstroms3 Da(-1) and the solvent content was 40.5%. The structure of a selenomethionine Sto-RNase HI mutant obtained using a MAD data set is currently being analysed.
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Affiliation(s)
- Dong-Ju You
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hyongi Chon
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuichi Koga
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazufumi Takano
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- CREST (Sosho Project), JST, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shigenori Kanaya
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Correspondence e-mail:
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24
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Abstract
DNA and a large proportion of RNA are antiparallel duplexes composed of an unvarying phosphosugar backbone surrounding uniformly stacked and highly similar base pairs. How do the myriad of enzymes (including ribozymes) that perform catalysis on nucleic acids achieve exquisite structure or sequence specificity? In all DNA and RNA polymerases and many nucleases and transposases, two Mg2+ ions are jointly coordinated by the nucleic acid substrate and catalytic residues of the enzyme. Based on the exquisite sensitivity of Mg2+ ions to the ligand geometry and electrostatic environment, we propose that two-metal-ion catalysis greatly enhances substrate recognition and catalytic specificity.
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Affiliation(s)
- Wei Yang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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25
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Chon H, Matsumura H, Koga Y, Takano K, Kanaya S. Crystal structure and structure-based mutational analyses of RNase HIII from Bacillus stearothermophilus: a new type 2 RNase H with TBP-like substrate-binding domain at the N terminus. J Mol Biol 2005; 356:165-78. [PMID: 16343535 DOI: 10.1016/j.jmb.2005.11.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 11/02/2005] [Accepted: 11/06/2005] [Indexed: 10/25/2022]
Abstract
Ribonuclease HIII (Bst-RNase HIII) from the moderate thermophile Bacillus stearothermophilus is a type 2 RNase H but shows poor amino acid sequence identity with another type 2 RNase H, RNase HII. It is composed of 310 amino acid residues and acts as a monomer. Bst-RNase HIII has a large N-terminal extension with unknown function and a unique active-site motif (DEDE), both of which are characteristics common to RNases HIII. To understand the role of these N-terminal extension and active-site residues, the crystal structure of Bst-RNase HIII was determined in both metal-free and metal-bound forms at 2.1-2.6 angstroms resolutions. According to these structures, Bst-RNase HIII consists of the N-terminal domain and C-terminal RNase H domain. The structures of the N and C-terminal domains were similar to those of TATA-box binding proteins and archaeal RNases HII, respectively. The steric configurations of the four conserved active-site residues were very similar to those of other type 1 and type 2 RNases H. Single Mn and Mg ions were coordinated with Asp97, Glu98, and Asp202, which correspond to Asp10, Glu48, and Asp70 of Escherichia coli RNase HI, respectively. The mutational studies indicated that the replacement of either one of these residues with Ala resulted in a great reduction of the enzymatic activity. Overproduction, purification, and characterization of the Bst-RNase HIII derivatives with N and/or C-terminal truncations indicated that the N-terminal domain and C-terminal helix are involved in substrate binding, but the former contributes to substrate binding more greatly than the latter.
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Affiliation(s)
- Hyongi Chon
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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26
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Nowotny M, Gaidamakov SA, Crouch RJ, Yang W. Crystal structures of RNase H bound to an RNA/DNA hybrid: substrate specificity and metal-dependent catalysis. Cell 2005; 121:1005-16. [PMID: 15989951 DOI: 10.1016/j.cell.2005.04.024] [Citation(s) in RCA: 476] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 04/07/2005] [Accepted: 04/19/2005] [Indexed: 11/23/2022]
Abstract
RNase H belongs to a nucleotidyl-transferase superfamily, which includes transposase, retroviral integrase, Holliday junction resolvase, and RISC nuclease Argonaute. We report the crystal structures of RNase H complexed with an RNA/DNA hybrid and a mechanism for substrate recognition and two-metal-ion-dependent catalysis. RNase H specifically recognizes the A form RNA strand and the B form DNA strand. Structure comparisons lead us to predict the catalytic residues of Argonaute and conclude that two-metal-ion catalysis is a general feature of the superfamily. In nucleases, the two metal ions are asymmetrically coordinated and have distinct roles in activating the nucleophile and stabilizing the transition state. In transposases, they are symmetrically coordinated and exchange roles to alternately activate a water and a 3'-OH for successive strand cleavage and transfer by a ping-pong mechanism.
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Affiliation(s)
- Marcin Nowotny
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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27
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Chon H, Matsumura H, Koga Y, Takano K, Kanaya S. Crystallization and preliminary X-ray diffraction study of thermostable RNase HIII from Bacillus stearothermophilus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2005; 61:293-5. [PMID: 16511022 PMCID: PMC1952286 DOI: 10.1107/s1744309105003659] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 02/02/2005] [Indexed: 11/11/2022]
Abstract
A thermostable ribonuclease HIII from Bacillus stearothermophilus (Bst RNase HIII) was crystallized and preliminary crystallographic studies were performed. Plate-like overlapping polycrystals were grown by the sitting-drop vapour-diffusion method at 283 K. Native X-ray diffraction data were collected to 2.8 A resolution using synchrotron radiation from station BL44XU at SPring-8. The crystals belong to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 66.73, b = 108.62, c = 48.29 A. Assuming one molecule per asymmetric unit, the VM value was 2.59 A3 Da(-1) and the solvent content was 52.2%.
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Affiliation(s)
- Hyongi Chon
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroyoshi Matsumura
- Department of Materials Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuichi Koga
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazufumi Takano
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- PRESTO, JST, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shigenori Kanaya
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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