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Saleh LY, Ora M, Lönnberg T. Organomercury oligonucleotide conjugates as artificial ribonucleases. J Inorg Biochem 2023; 247:112331. [PMID: 37480764 DOI: 10.1016/j.jinorgbio.2023.112331] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/03/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023]
Abstract
Two oligonucleotide conjugates sharing the same sequence but incorporating a different 5'-terminal organometallic moiety were synthesized, by either direct mercuration in solution or oximation with an organomercury aldehyde on solid support. The potential of these conjugates to serve as new type of artificial ribonucleases was tested with a complementary 2´-O-methyl-RNA target sequence featuring a single cleavable RNA phosphodiester linkage. Both organomercury oligonucleotides greatly outperformed their metal-free counterparts as well as the previously reported small molecule organomercury RNA cleaving agent in catalytic activity, providing an important proof-of-concept. Compared to state-of-the-art metal-dependent artificial ribonucleases, however, the observed activity was modest.
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Affiliation(s)
- Lange Yakubu Saleh
- Department of Chemistry, University of Turku, Henrikinkatu 2, 20500 Turku, Finland
| | - Mikko Ora
- Department of Chemistry, University of Turku, Henrikinkatu 2, 20500 Turku, Finland
| | - Tuomas Lönnberg
- Department of Chemistry, University of Turku, Henrikinkatu 2, 20500 Turku, Finland.
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2
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Wang X, Shu J, Ni T, Xu C, Xu B, Liu X, Zhang K, Jiang W. Transesterification of RNA model induced by novel dinuclear copper (II) complexes with bis-tridentate imidazole derivatives. J Biol Inorg Chem 2023:10.1007/s00775-023-02000-6. [PMID: 37140680 DOI: 10.1007/s00775-023-02000-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 04/15/2023] [Indexed: 05/05/2023]
Abstract
Two novel bis-tridentate imidazole derivatives were conveniently synthesized using a 'one-pot' method. Their dinuclear (Cu2L1Cl4, Cu2L2Cl4) and mononuclear (CuL1Cl2, CuL2Cl2∙H2O) copper (II) complexes were synthesized to comparably evaluate their reactivities in the hydrolytic cleavage of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP) as a classic RNA model. Single crystals of Cu2L1Cl4 and Cu2L2Cl4 indicate that both of them are centrosymmetric, and each central copper ion is penta-coordinated. Regarding the transesterification of HPNP, both of dinuclear ones exhibited excess one order of magnitude rate enhancement in contrast with auto-hydrolysis reaction. Under comparable conditions, dinuclear complexes displayed no more than twofold increase in activity over their mononuclear analogues, which verifies the lack of binuclear cooperation effect due to long Cu-to-Cu space.
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Affiliation(s)
- Xiuyang Wang
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
| | - Jun Shu
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
| | - Tong Ni
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
| | - Chengxu Xu
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
| | - Bin Xu
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
- Key Laboratory of Green Catalysis of Sichuan Institute of High Education, Sichuan University of Science and Engineering, Sichuan, 643000, Zigong, People's Republic of China
| | - Xiaoqiang Liu
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
- Key Laboratory of Green Catalysis of Sichuan Institute of High Education, Sichuan University of Science and Engineering, Sichuan, 643000, Zigong, People's Republic of China
| | - Kaiming Zhang
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China
- Key Laboratory of Green Catalysis of Sichuan Institute of High Education, Sichuan University of Science and Engineering, Sichuan, 643000, Zigong, People's Republic of China
| | - Weidong Jiang
- School of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, 643000, Sichuan, People's Republic of China.
- Key Laboratory of Green Catalysis of Sichuan Institute of High Education, Sichuan University of Science and Engineering, Sichuan, 643000, Zigong, People's Republic of China.
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Putnam WC, Bashkin JK. Oligonucleotides containing abasic threoninol-terpyridine residues as potential artificial ribonucleases. J Inorg Biochem 2022; 232:111831. [DOI: 10.1016/j.jinorgbio.2022.111831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 04/04/2022] [Accepted: 04/11/2022] [Indexed: 11/24/2022]
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4
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Ren M, Cheng Y, Duan Q, Zhou C. Transesterification Reaction and the Repair of Embedded Ribonucleotides in DNA Are Suppressed upon the Assembly of DNA into Nucleosome Core Particles †. Chem Res Toxicol 2019; 32:926-934. [PMID: 30990021 DOI: 10.1021/acs.chemrestox.9b00059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ribonucleotides can be incorporated into DNA through many different cellular processes, and abundant amounts of ribonucleotides are detected in genomic DNA. Embedded ribonucleotides lead to genomic instability through either spontaneous ribonucleotide cleavage via internal transesterification or by inducing mutagenesis, recombination, and chromosome rearrangements. Ribonucleotides misincorporated in genomic DNA can be removed by the ribonucleotide excision repair (RER) pathway in which RNase HII initiates the repair by cleaving the 5'-phosphate of the ribonucleotide. Herein, based on in vitro reconstituted nucleosome core particles (NCPs) containing a single ribonucleotide at different positions, we studied the kinetics of ribonucleotide cleavage via the internal transesterification reaction and repair of the ribonucleotides by RNase HII in NCPs. Our results show that ribonucleotide cleavage via the internal transesterification in NCPs is suppressed compared to that in free DNA. DNA bending and structural rigidity account for the suppressed ribonucleotide cleavage in NCPs. Ribonucleotide repair by RNase HII in NCPs exhibits a strong correlation between the translational and rotational positions of the ribonucleotides. An embedded ribonucleotide located at the entry site while facing outward in NCP is repaired as efficiently as that in free DNA. However, the repair of those located in the central part of NCPs and facing inward are inhibited by up to 273-fold relative to those in free dsDNA. The difference in repair efficiency appears to arise from their different accessibility to repair enzymes in NCPs. This study reveals that a ribonucleotide misincorporated in DNA assembled into NCPs is protected against cleavage. Hence, the spontaneous cleavage of the misincorporated ribonucleotides under physiological conditions is not an essential threat to the stability of chromatin DNA. Instead, their decreased repair efficiency in NCPs may result in numerous and persistent ribonucleotides in genomic DNA, which could exert other deleterious effects on DNA such as mutagenesis and recombination.
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Affiliation(s)
- Mengtian Ren
- State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Yiran Cheng
- State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Qian Duan
- State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Chuanzheng Zhou
- State Key Laboratory of Elemento-Organic Chemistry and Department of Chemical Biology, College of Chemistry , Nankai University , Tianjin 300071 , China
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5
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Desbouis D, Troitsky IP, Belousoff MJ, Spiccia L, Graham B. Copper(II), zinc(II) and nickel(II) complexes as nuclease mimetics. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2011.12.005] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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6
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Ye JD, Li NS, Dai Q, Piccirilli JA. The mechanism of RNA strand scission: an experimental measure of the Brønsted coefficient, beta nuc. Angew Chem Int Ed Engl 2007; 46:3714-7. [PMID: 17415726 DOI: 10.1002/anie.200605124] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jing-Dong Ye
- Howard Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
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7
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Ye JD, Li NS, Dai Q, Piccirilli J. The Mechanism of RNA Strand Scission: An Experimental Measure of the Brønsted Coefficient,βnuc. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200605124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Mengel-Jørgensen J, Sanchez JJ, Børsting C, Kirpekar F, Morling N. Typing of multiple single-nucleotide polymorphisms using ribonuclease cleavage of DNA/RNA chimeric single-base extension primers and detection by MALDI-TOF mass spectrometry. Anal Chem 2007; 77:5229-35. [PMID: 16097763 DOI: 10.1021/ac0502044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel single-base extension (SBE) assay using cleavable and noncleavable SBE primers in the same reaction mix is described. The cleavable SBE primers consisted of deoxyribonucleotides and one ribonucleotide (hereafter denoted chimeric primers), whereas the noncleavable SBE primers consisted of only deoxyribonucleotides (hereafter denoted standard primers). Biotin-labeled ddNTPs were used in the SBE reaction, and the SBE products were purified using the monomeric avidin triethylamine purification protocol, ensuring that only primers extended with a biotin-ddNTP in the 3'-end were isolated. A ribonuclease mix was developed to specifically cleave the chimeric primers, irrespective of the base of the ribonucleotide, whereas standard primers without a ribonucleotide were unaffected by the ribonuclease treatment. The SBE products were analyzed in linear mode using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. The cleaved SBE products were detected in the 2000-5500 m/z range, and the noncleaved SBE products were detected in the 5500-10 000 m/z range. The method was validated by typing 17 Y chromosome single-nucleotide polymorphisms in 100 males with a 17-plex SBE package containing 9 chimeric primers and 8 standard primers.
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Affiliation(s)
- J Mengel-Jørgensen
- Department of Forensic Genetics, Institute of Forensic Medicine, University of Copenhagen, 11 Frederik V's Vej, DK-2100 Copenhagen Ø, Denmark.
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9
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Fry FH, Fischmann AJ, Belousoff MJ, Spiccia L, Brügger J. Kinetics and Mechanism of Hydrolysis of a Model Phosphate Diester by [Cu(Me3tacn)(OH2)2]2+ (Me3tacn = 1,4,7-Trimethyl-1,4,7-triazacyclononane). Inorg Chem 2005; 44:941-50. [PMID: 15859272 DOI: 10.1021/ic049469b] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The kinetics of hydrolysis of bis(p-nitrophenyl)phosphate (BNPP) by [Cu(Me3tacn)(OH2)2]2+ has been studied by spectrophotometrical monitoring of the release of the p-nitrophenylate ion from BNPP. The reaction was followed for up to 8000 min at constant BNPP concentration (15 microM) and ionic strength (0.15 M) and variable concentration of complex (1.0-7.5 mM) and temperature (42.5-65.0 degrees C). Biphasic kinetic traces were observed, indicating that the complex promotes the cleavage of BNPP to NPP [(p-nitrophenyl)phosphate] and then cleavage of the latter to phosphate, the two processes differing in rate by 50-100-fold. Analysis of the more amenable cleavage of BNPP revealed that the rate of BNPP cleavage is among the highest measured for mononuclear copper(II) complexes and is slightly higher than that reported for the close analogue [Cu(iPr3tacn)(OH2)2]2+. Detailed analysis required the determination of the pKa for [Cu(Me3tacn)(OH2)2]2+ and the constant for the dimerization of the conjugate base to [(Me3tacn)Cu(OH)2Cu(Me3tacn)]2+ (Kdim). Thermodynamic parameters derived from spectrophotometric pH titration and the analysis of the kinetic data were in reasonable agreement. Second-order rate constants for cleavage of BNPP by [Cu(Me3tacn)(OH2)(OH)]+ and associated activation parameters were obtained from initial rate analysis (k = 0.065 M(-1) s(-1) at 50.0 degrees C, deltaH = 56+/-6 kJ mol(-1), deltaS = -95+/-18 J K(-1) mol(-1)) and biphasic kinetic analysis (k = 0.14 M(-1) s(-1) at 50.0 degrees C, deltaH = 55+/-6 kJ mol(-1), deltaS = -92+/-20 J K(-1) mol(-1)). The negative entropy of activation is consistent with a concerted mechanism with considerable associative character. The complex was found to catalyze the cleavage of BNPP with turnover rates of up to 1 per day. Although these turnover rates can be considered low from an application point of view, the ability of the complexes to catalyze phosphate ester cleavage is clearly demonstrated.
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Affiliation(s)
- Fiona H Fry
- School of Chemistry, Monash University, Victoria 3800, Australia
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10
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Copper Containing Nuclease Mimics: Synthetic Models and Biochemical Applications. ARTIFICIAL NUCLEASES 2004. [DOI: 10.1007/978-3-642-18510-6_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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11
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Ordoukhanian P, Joyce GF. RNA-cleaving DNA enzymes with altered regio- or enantioselectivity. J Am Chem Soc 2002; 124:12499-506. [PMID: 12381192 DOI: 10.1021/ja027467p] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In vitro evolution methods were used to obtain DNA enzymes that cleave either a 2',5'-phosphodiester following a D-ribonucleotide or a 3',5'-phosphodiester following an L-ribonucleotide. Both enzymes can operate in an intermolecular reaction format with multiple turnover. The DNA enzyme that cleaves a 2',5'-phosphodiester exhibits a k(cat) of approximately 0.01 min(-1) and catalytic efficiency, k(cat)/K(m), of approximately 10(8) M(-1) min(-1). The enzyme that cleaves an L-ribonucleotide is about 10-fold slower and has a catalytic efficiency of approximately 4 x 10(5) M(-1) min(-1). Both enzymes require a divalent metal cation for their activity and have optimal catalytic rate at pH 7-8 and 35-50 degrees C. In a comparison of each enzyme's activity with either its corresponding substrate that contains an unnatural ribonucleotide or a substrate that instead contains a standard ribonucleotide, the 2',5'-phosphodiester-cleaving DNA enzyme exhibited a regioselectivity of 6000-fold, while the L-ribonucleotide-cleaving DNA enzyme exhibited an enantioselectivity of 40-fold. These molecules demonstrate how in vitro evolution can be used to obtain regio- and enantioselective catalysts that exhibit specificities for nonnatural analogues of biological compounds.
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Affiliation(s)
- Phillip Ordoukhanian
- Departments of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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12
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Park C, Kelemen BR, Klink TA, Sweeney RY, Behlke MA, Eubanks SR, Raines RT. Fast, facile, hypersensitive assays for ribonucleolytic activity. Methods Enzymol 2002; 341:81-94. [PMID: 11582813 DOI: 10.1016/s0076-6879(01)41146-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- C Park
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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13
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Bashkin JK. Hydrolysis of phosphates, esters and related substrates by models of biological catalysts. Curr Opin Chem Biol 1999; 3:752-8. [PMID: 10600728 DOI: 10.1016/s1367-5931(99)00036-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Why study hydrolases, and why model them? First, hydrolases themselves are of fundamental importance and utility. Examples of their utility in organic synthesis include kinetic resolutions of optical isomers. Restriction endonucleases (DNA hydrolases) are key tools for biotechnology and are vital biological catalysts. Peptidases are necessary for protein digestion and can be harnessed to perform the reverse reaction (peptide synthesis). Thus, for these and many other reasons, hydrolases receive the attention of fundamental and applied research. Models of hydrolases can contribute to our understanding of reaction mechanisms and may also supplant the enzymes as useful catalysts under some conditions. Altering or even increasing the specificity of natural catalysts are also goals of these model studies.
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Affiliation(s)
- J K Bashkin
- Monsanto Company R3A, St Louis, MO 63167, USA. james.k.
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14
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Jenkins LA, Bashkin JK, Pennock JD, Florián J, Warshel A. Catalytic Hydrolysis of Adenosine 2‘,3‘-Cyclic Monophosphate by CuII Terpyridine. Inorg Chem 1999. [DOI: 10.1021/ic990228r] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lisa A. Jenkins
- Department of Chemistry, Washington University, Box 1134, 1 Brookings Drive, St. Louis, Missouri 63130-4899, and Department Chemistry, University of Southern California, Los Angeles, California 90089-1062
| | - James K. Bashkin
- Department of Chemistry, Washington University, Box 1134, 1 Brookings Drive, St. Louis, Missouri 63130-4899, and Department Chemistry, University of Southern California, Los Angeles, California 90089-1062
| | - Jennifer D. Pennock
- Department of Chemistry, Washington University, Box 1134, 1 Brookings Drive, St. Louis, Missouri 63130-4899, and Department Chemistry, University of Southern California, Los Angeles, California 90089-1062
| | - Jan Florián
- Department of Chemistry, Washington University, Box 1134, 1 Brookings Drive, St. Louis, Missouri 63130-4899, and Department Chemistry, University of Southern California, Los Angeles, California 90089-1062
| | - Arieh Warshel
- Department of Chemistry, Washington University, Box 1134, 1 Brookings Drive, St. Louis, Missouri 63130-4899, and Department Chemistry, University of Southern California, Los Angeles, California 90089-1062
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15
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Li Y, Breaker RR. Kinetics of RNA Degradation by Specific Base Catalysis of Transesterification Involving the 2‘-Hydroxyl Group. J Am Chem Soc 1999. [DOI: 10.1021/ja990592p] [Citation(s) in RCA: 389] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yingfu Li
- Contribution from the Department of Molecular, Cellular and Developmental Biology, Yale University, PO Box 208103, New Haven, Connecticut 06520-8103
| | - Ronald R. Breaker
- Contribution from the Department of Molecular, Cellular and Developmental Biology, Yale University, PO Box 208103, New Haven, Connecticut 06520-8103
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16
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Kelemen BR, Raines RT. Extending the limits to enzymatic catalysis: diffusion of ribonuclease A in one dimension. Biochemistry 1999; 38:5302-7. [PMID: 10220316 DOI: 10.1021/bi990325w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bovine pancreatic ribonuclease A (RNase A) is a distributive endoribonuclease that catalyzes the cleavage of the P-O5' bond of RNA on the 3' side of pyrimidine residues. Here, RNase A is shown to cleave the P-O5' bond of a pyrimidine ribonucleotide faster when the substrate is embedded within a longer tract of poly(adenylic acid) [poly(A)] or poly(deoxyadenylic acid) [poly(dA)]. These data indicate that a ribonuclease can diffuse in one dimension along a single-stranded nucleic acid. This facilitated diffusion is mediated by Coulombic interactions, as the extent is diminished by the addition of NaCl. RNase A is more effective at cleaving a pyrimidine ribonucleotide embedded within a poly(dA) tract than within a poly(deoxycytidylic acid) [poly(dC)] tract. T45G RNase A, which catalyzes the processive cleavage of poly(A) but the distributive cleavage of poly(cytidylic acid) [poly(C)], has the same preference. Apparently, processive catalysis by the T45G enzyme arises from the expanded substrate specificity of the variant superimposed upon an intrinsic ability to diffuse along poly(A). Homologous ribonucleases with cytotoxic activity may rely on facilitated diffusion along poly(A) tails for efficient degradation of the essential information encoded by cellular mRNA.
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Affiliation(s)
- B R Kelemen
- Department of Biochemistry, Department of Chemistry, University of Wisconsin-Madison 53706, USA
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17
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Trawick BN, Daniher AT, Bashkin JK. Inorganic Mimics of Ribonucleases and Ribozymes: From Random Cleavage to Sequence-Specific Chemistry to Catalytic Antisense Drugs. Chem Rev 1998; 98:939-960. [PMID: 11848920 DOI: 10.1021/cr960422k] [Citation(s) in RCA: 220] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Bobby N. Trawick
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
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Affiliation(s)
- Ronald T. Raines
- Departments of Biochemistry and Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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Affiliation(s)
- J. A. Cowan
- The Evans Laboratory of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
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Kuimelis RG, McLaughlin LW. Application of a 5'-bridging phosphorothioate to probe divalent metal and hammerhead ribozyme mediated RNA cleavage. Bioorg Med Chem 1997; 5:1051-61. [PMID: 9222498 DOI: 10.1016/s0968-0896(97)00041-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This paper describes the preparation and application of a chimeric DNA/RNA oligonucleotide that contains a single 5'-bridging phosphorothioate linkage adjacent to a ribonucleotide and embedded in an otherwise all-DNA sequence. The influence of pH, divalent metal cation, hybridization, and secondary structure on the susceptibility of the thio linkage towards transesterification is investigated in an effort to better understand the metal-phosphorothioate interactions and the basis for catalysis. In addition to the chemical cleavage, we have examined the hammerhead ribozyme mediated cleavage of the 5'-bridging phosphorothioate linkage specifically to test the hypothesis that the ribozyme employs a second metal cofactor, which functions as a Lewis acid, to catalyze transesterification. The results of our kinetics experiments do not support this double-metal model.
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Affiliation(s)
- R G Kuimelis
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02167, USA
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