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Vianney YM, Jana J, Weisz K. A pH-Responsive Topological Switch Based on a DNA Quadruplex-Duplex Hybrid. Chemistry 2024:e202400722. [PMID: 38497675 DOI: 10.1002/chem.202400722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 03/19/2024]
Abstract
A guanine-rich oligonucleotide based on a human telomeric sequence but with the first three-nucleotide intervening stretch replaced by a putative 15-nucleotide hairpin-forming sequence shows a pH-dependent folding into different quadruplex-duplex hybrids in a potassium containing buffer. At slightly acidic pH, the quadruplex domain adopts a chair-type conformation. Upon increasing the pH, a transition with a midpoint close to neutral pH to a major and minor (3+1) hybrid topology with either a coaxially stacked or orthogonally oriented duplex stem-loop occurs. NMR-derived high-resolution structures reveal that an adenine protonation is prerequisite for the formation of a non-canonical base quartet, capping the outer G-tetrad at the quadruplex-duplex interface and stabilizing the antiparallel chair conformation in an acidic environment. Being directly associated with interactions at the quadruplex-duplex interface, this unique pH-dependent topological transition is fully reversible. Coupled with a conformation-sensitive optical readout demonstrated as a proof of concept using the fluorescent dye thiazole orange, the present quadruplex-duplex hybrid architecture represents a potentially valuable pH-sensing system responsive in a physiological pH range of 7±1.
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Affiliation(s)
- Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489, Greifswald, Germany
| | - Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489, Greifswald, Germany
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Vianney YM, Dierks D, Weisz K. Structural Differences at Quadruplex-Duplex Interfaces Enable Ligand-Induced Topological Transitions. Adv Sci (Weinh) 2024:e2309891. [PMID: 38477454 DOI: 10.1002/advs.202309891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/13/2024] [Indexed: 03/14/2024]
Abstract
Quadruplex-duplex (QD) junctions, which represent unique structural motifs of both biological and technological significance, have been shown to constitute high-affinity binding sites for various ligands. A QD hybrid construct based on a human telomeric sequence, which harbors a duplex stem-loop in place of a short lateral loop, is structurally characterized by NMR. It folds into two major species with a (3+1) hybrid and a chair-type (2+2) antiparallel quadruplex domain coexisting in a K+ buffer solution. The antiparallel species is stabilized by an unusual capping structure involving a thymine and protonated adenine base AH+ of the lateral loop facing the hairpin duplex to form a T·AH+ ·G·C quartet with the interfacial G·C base pair at neutral pH. Addition and binding of Phen-DC3 to the QD hybrid mixture by its partial intercalation at corresponding QD junctions leads to a topological transition with exclusive formation of the (3+1) hybrid fold. In agreement with the available experimental data, such an unprecedented discrimination of QD junctions by a ligand can be rationalized following an induced fit mechanism.
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Affiliation(s)
- Yoanes Maria Vianney
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489, Greifswald, Germany
| | - Dorothea Dierks
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489, Greifswald, Germany
| | - Klaus Weisz
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489, Greifswald, Germany
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3
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Jana J, Vianney YM, Weisz K. Impact of loop length and duplex extensions on the design of hybrid-type G-quadruplexes. Chem Commun (Camb) 2024; 60:854-857. [PMID: 38131370 DOI: 10.1039/d3cc05625b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
A G-rich core sequence G3-TCA-G3-T1,2-G3-T1,2-G3 can be designed to fold into a parallel or into two different (3+1) hybrid-type G-quadruplexes, among them an elusive topology with one lateral followed by two propeller loops. Favored folds can be rationalized based on the number of intervening thymidines and on additional complementary flanking sequences.
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Affiliation(s)
- Jagannath Jana
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff Str. 4, Greifswald D-17489, Germany.
| | - Yoanes Maria Vianney
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff Str. 4, Greifswald D-17489, Germany.
| | - Klaus Weisz
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff Str. 4, Greifswald D-17489, Germany.
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Vianney YM, Schröder N, Jana J, Chojetzki G, Weisz K. Showcasing Different G-Quadruplex Folds of a G-Rich Sequence: Between Rule-Based Prediction and Butterfly Effect. J Am Chem Soc 2023; 145:22194-22205. [PMID: 37751488 DOI: 10.1021/jacs.3c08336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
In better understanding the interactions of G-quadruplexes in a cellular or noncellular environment, a reliable sequence-based prediction of their three-dimensional fold would be extremely useful, yet is often limited by their remarkable structural diversity. A G-rich sequence related to a promoter sequence of the PDGFR-β nuclease hypersensitivity element (NHE) comprises a G3-G3-G2-G4-G3 pattern of five G-runs with two to four G residues. Although the predominant formation of three-layered canonical G-quadruplexes with uninterrupted G-columns can be expected, minimal base substitutions in a non-G-tract domain were shown to guide folding into either a basket-type antiparallel quadruplex, a parallel-stranded quadruplex with an interrupted G-column, a quadruplex with a V-shaped loop, or a (3+1) hybrid quadruplex. A 3D NMR structure for each of the different folds was determined. Supported by thermodynamic profiling on additional sequence variants, formed topologies were rationalized by the identification and assessment of specific critical interactions of loop and overhang residues, giving valuable insights into their contribution to favor a particular conformer. The variability of such tertiary interactions, together with only small differences in quadruplex free energies, emphasizes current limits for a reliable sequence-dependent prediction of favored topologies from sequences with multiple irregularly positioned G-tracts.
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Affiliation(s)
- Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, D-17489 Greifswald, Germany
| | - Nina Schröder
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, D-17489 Greifswald, Germany
| | - Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, D-17489 Greifswald, Germany
| | - Gregor Chojetzki
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, D-17489 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, D-17489 Greifswald, Germany
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Vianney YM, Weisz K. High-affinity binding at quadruplex-duplex junctions: rather the rule than the exception. Nucleic Acids Res 2022; 50:11948-11964. [PMID: 36416262 PMCID: PMC9723630 DOI: 10.1093/nar/gkac1088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 11/24/2022] Open
Abstract
Quadruplex-duplex (Q-D) junctions constitute unique structural motifs in genomic sequences. Through comprehensive calorimetric as well as high-resolution NMR structural studies, Q-D junctions with a hairpin-type snapback loop coaxially stacked onto an outer G-tetrad were identified to be most effective binding sites for various polycyclic quadruplex ligands. The Q-D interface is readily recognized by intercalation of the ligand aromatic core structure between G-tetrad and the neighboring base pair. Based on the thermodynamic and structural data, guidelines for the design of ligands with enhanced selectivity towards a Q-D interface emerge. Whereas intercalation at Q-D junctions mostly outcompete stacking at the quadruplex free outer tetrad or intercalation between duplex base pairs to varying degrees, ligand side chains considerably contribute to the selectivity for a Q-D target over other binding sites. In contrast to common perceptions, an appended side chain that additionally interacts within the duplex minor groove may confer only poor selectivity. Rather, the Q-D selectivity is suggested to benefit from an extension of the side chain towards the exposed part of the G-tetrad at the junction. The presented results will support the design of selective high-affinity binding ligands for targeting Q-D interfaces in medicinal but also technological applications.
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Affiliation(s)
- Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489 Greifswald, Germany
| | - Klaus Weisz
- To whom correspondence should be addressed. Tel: +49 3834 420 4426; Fax: +49 3834 420 4427;
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Jana J, Vianney YM, Schröder N, Weisz K. Guiding the folding of G-quadruplexes through loop residue interactions. Nucleic Acids Res 2022; 50:7161-7175. [PMID: 35758626 PMCID: PMC9262619 DOI: 10.1093/nar/gkac549] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/25/2022] [Accepted: 06/14/2022] [Indexed: 12/24/2022] Open
Abstract
A G-rich sequence was designed to allow folding into either a stable parallel or hybrid-type topology. With the parent sequence featuring coexisting species, various related sequences with single and double mutations and with a shortened central propeller loop affected the topological equilibrium. Two simple modifications, likewise introduced separately to all sequences, were employed to lock folds into one of the topologies without noticeable structural alterations. The unique combination of sequence mutations, high-resolution NMR structural information, and the thermodynamic stability for both topological competitors identified critical loop residue interactions. In contrast to first loop residues, which are mostly disordered and exposed to solvent in both propeller and lateral loops bridging a narrow groove, the last loop residue in a lateral three-nucleotide loop is engaged in stabilizing stacking interactions. The propensity of single-nucleotide loops to favor all-parallel topologies by enforcing a propeller-like conformation of an additional longer loop is shown to result from their preference in linking two outer tetrads of the same tetrad polarity. Taken together, the present studies contribute to a better structural and thermodynamic understanding of delicate loop interactions in genomic and artificially designed quadruplexes, e.g. when employed as therapeutics or in other biotechnological applications.
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Affiliation(s)
- Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, D-17489 Greifswald, Germany
| | | | - Nina Schröder
- Institute of Biochemistry, Universität Greifswald, D-17489 Greifswald, Germany
| | - Klaus Weisz
- To whom correspondence should be addressed. Tel: +49 3834 420 4426; Fax: +49 3834 420 4427;
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Abstract
Quadruplex‐duplex (Q‐D) junctions are increasingly considered promising targets for medicinal and technological applications. Here, a Q‐D hybrid with a hairpin‐type snapback loop coaxially stacked onto the quadruplex 3’‐outer tetrad was designed and employed as a target structure for the indoloquinoline ligand SYUIQ‐5. NMR spectral analysis demonstrated high‐affinity binding of the ligand at the quadruplex‐duplex interface with association constants determined by isothermal titration calorimetry of about 107 M−1 and large exothermicities ΔH° of −14 kcal/mol in a 120 mM K+ buffer at 40 °C. Determination of the ligand‐bound hybrid structure revealed intercalation of SYUIQ‐5 between 3’‐outer tetrad and the neighboring CG base pair, maximizing π–π stacking as well as electrostatic interactions with guanine carbonyl groups in close vicinity to the positively charged protonated quinoline nitrogen of the tetracyclic indoloquinoline. Exhibiting considerable flexibility, the SYUIQ‐5 sidechain resides in the duplex minor groove. Based on comparative binding studies with the non‐substituted N5‐methylated indoloquinoline cryptolepine, the sidechain is suggested to confer additional affinity and to fix the alignment of the intercalated indoloquinoline aromatic core. However, selectivity for the Q‐D junction mostly relies on the geometry and charge distribution of the indoloquinoline ring system. The presented results are expected to provide valuable guidelines for the design of ligands specifically targeting Q‐D interfaces.
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Affiliation(s)
- Yoanes Maria Vianney
- Universität Greifswald Mathematisch-Naturwissenschaftliche Fakultät: Universitat Greifswald Mathematisch-Naturwissenschaftliche Fakultat, Institut für Biochemie, Felix-Hausdorff-Str. 4, 17489, Greifswald, GERMANY
| | - Klaus Weisz
- Universität Greifswald, Institut für Biochemie, Felix-Hausdorff-Str. 4, 17487, Greifswald, GERMANY
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Abstract
G-quadruplexes have attracted growing interest in recent years due to their occurrence in vivo and their possible biological functions. In addition to being promising targets for drug design, these four-stranded nucleic acid structures have also been recognized as versatile tools for various technological applications. Whereas a large number of studies have yielded insight into their remarkable structural diversity, our current knowledge on G-quadruplex stabilities as a function of sequence and environmental factors only gradually emerges with an expanding collection of thermodynamic data. This minireview provides an overview of general rules that may be used to better evaluate quadruplex thermodynamic stabilities but also discusses present challenges in predicting most stable folds for a given sequence and environment.
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Affiliation(s)
- Jagannath Jana
- Institute of BiochemistryUniversität GreifswaldFelix-Hausdorff Str. 417489GreifswaldGermany
| | - Klaus Weisz
- Institute of BiochemistryUniversität GreifswaldFelix-Hausdorff Str. 417489GreifswaldGermany
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Abstract
AbstractNucleic acids can adopt various secondary structures including double-, triple-, and tetra-stranded helices that differ by the specific hydrogen bond mediated pairing pattern between their nucleobase constituents. Whereas double-helical DNA relies on Watson–Crick base pairing to play a prominent role in storing genetic information, G-quadruplexes are tetra-stranded structures that are formed by the association of guanine bases from G-rich DNA and RNA sequences. During the last few decades, G-quadruplexes have attracted considerable interest after the realization that they form and exert regulatory functions in vivo. In addition, quadruplex architectures have also been recognized as versatile and powerful tools in a growing number of technological applications. To appreciate the astonishing structural diversity of these tetra-stranded structures and to give some insight into basic interactions that govern their folding, this article gives an overview of quadruplex structures and rules associated with the formation of different topologies. A brief discussion will also focus on nonconventional quadruplexes as well as on general principles when targeting quadruplexes with ligands.
Graphic abstract
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10
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Abstract
Canonical G‐quadruplexes can adopt a variety of different topologies depending on the arrangement of propeller, lateral, or diagonal loops connecting the four G‐columns. A novel intramolecular G‐quadruplex structure is derived through inversion of the last G‐tract of a three‐layered parallel fold, associated with the transition of a single propeller into a lateral loop. The resulting (3+1) hybrid fold features three syn⋅anti⋅anti⋅anti G‐tetrads with a 3’‐terminal all‐syn G‐column. Although the ability of forming a duplex stem‐loop between G‐tracts seems beneficial for a propeller‐to‐lateral loop rearrangement, unmodified G‐rich sequences resist folding into the new (3+1) topology. However, refolding can be driven by the incorporation of syn‐favoring guanosine analogues into positions of the fourth G‐stretch. The presented hybrid‐type G‐quadruplex structure as determined by NMR spectroscopy may provide for an additional scaffold in quadruplex‐based technologies.
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Affiliation(s)
- Swantje Mohr
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
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Vianney YM, Weisz K. First Tandem Repeat of a Potassium Channel KCNN4 Minisatellite Folds into a V-Loop G-Quadruplex Structure. Biochemistry 2021; 60:1337-1346. [PMID: 33844501 DOI: 10.1021/acs.biochem.1c00043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The KCNN4 gene encoding a potassium channel protein whose expression has been correlated with tumor progression was found to comprise a guanine-rich minisatellite region with the ability to form a putative G-quadruplex (G4). Given the suggested regulatory role of G4s in gene expression, G-quadruplex formation for the polymorphic first repeat of the minisatellite was studied by nuclear magnetic resonance spectroscopy. A stable G-quadruplex of a truncated mutant sequence was shown to represent one of several coexisting species of the wild-type sequence. The high-resolution structure features a noncanonical G4 with a broken G-column and a V-shaped loop. The presence of a 3'-flanking thymidine interacting with the lateral loop preceding the V loop seems to be critical for the formation of this G4 topology. On the contrary, an additional 5'-flanking residue disfavored but still allowed folding into the V-loop structure. The latter may therefore serve as a putative therapeutic target in strategies for G4-based modulation of KCNN4 expression.
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Affiliation(s)
- Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
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Vianney YM, Purwanto MGM, Weisz K. G-Quadruplex Formation in a Putative Coding Region of White Spot Syndrome Virus: Structural and Thermodynamic Aspects. Chembiochem 2021; 22:1932-1935. [PMID: 33710715 PMCID: PMC8252560 DOI: 10.1002/cbic.202100064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/04/2021] [Indexed: 01/05/2023]
Abstract
White spot disease (WSD) is one of the most devastating viral infections of crustaceans caused by the white spot syndrome virus (WSSV). A conserved sequence WSSV131 in the DNA genome of WSSV was found to fold into a polymorphic G‐quadruplex structure. Supported by two mutant sequences with single G→T substitutions in the third G4 tract of WSSV131, circular dichroism and NMR spectroscopic analyses demonstrate folding of the wild‐type sequence into a three‐tetrad parallel topology comprising three propeller loops with a major 1 : 3 : 1 and a minor 1 : 2 : 2 loop length arrangement. A thermodynamic analysis of quadruplex formation by differential scanning calorimetry (DSC) indicates a thermodynamically more stable 1 : 3 : 1 loop isomer. DSC also revealed the formation of additional highly stable multimeric species with populations depending on potassium ion concentration.
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Affiliation(s)
- Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, 17489, Greifswald, Germany
| | | | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff Str. 4, 17489, Greifswald, Germany
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Jana J, Mohr S, Vianney YM, Weisz K. Structural motifs and intramolecular interactions in non-canonical G-quadruplexes. RSC Chem Biol 2021; 2:338-353. [PMID: 34458788 PMCID: PMC8341446 DOI: 10.1039/d0cb00211a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/14/2021] [Indexed: 12/12/2022] Open
Abstract
Guanine(G)-rich DNA or RNA sequences can assemble or intramolecularly fold into G-quadruplexes formed through the stacking of planar G·G·G·G tetrads in the presence of monovalent cations. These secondary nucleic acid structures have convincingly been shown to also exist within a cellular environment exerting important regulatory functions in physiological processes. For identifying nucleic acid segments prone to quadruplex formation, a putative quadruplex sequence motif encompassing closely spaced tracts of three or more guanosines is frequently employed for bioinformatic search algorithms. Depending on the number and type of intervening residues as well as on solution conditions, such sequences may fold into various canonical G4 topologies with continuous G-columns. On the other hand, a growing number of sequences capable of quadruplex formation feature G-deficient guanine tracts, escaping the conservative consensus motif. By folding into non-canonical quadruplex structures, they adopt unique topologies depending on their specific sequence context. These include G-columns with only two guanines, bulges, snapback loops, D- and V-shaped loops as well as interlocked structures. This review focuses on G-quadruplex species carrying such distinct structural motifs. It evaluates characteristic features of their non-conventional scaffold and highlights principles of stabilizing interactions that also allow for their folding into stable G-quadruplex structures.
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Affiliation(s)
- Jagannath Jana
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Swantje Mohr
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
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Jana J, Weisz K. A Thermodynamic Perspective on Potential G-Quadruplex Structures as Silencer Elements in the MYC Promoter. Chemistry 2020; 26:17242-17251. [PMID: 32761687 PMCID: PMC7839732 DOI: 10.1002/chem.202002985] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/31/2020] [Indexed: 01/10/2023]
Abstract
Multiple G‐tracts within the promoter region of the c‐myc oncogene may fold into various G‐quadruplexes with the recruitment of different tracts and guanosine residues for the G‐core assembly. Thermodynamic profiles for the folding of wild‐type and representative truncated as well as mutated sequences were extracted by comprehensive DSC experiments. The unique G‐quadruplex involving consecutive G‐tracts II–V with formation of two one‐nucleotide and one central two‐nucleotide propeller loop, previously proposed to be the biologically most relevant species, was found to be the most stable fold in terms of its Gibbs free energy of formation at ambient temperatures. Its stability derives from its short propeller loops but also from the favorable type of loop residues. Whereas quadruplex folds with long propeller loops are significantly disfavored, a snap‐back loop structure formed by incorporating a 3’‐terminal guanosine into the empty position of a tetrad seems highly competitive based on its thermodynamic stability. However, its destabilization by extending the 3’‐terminus questions the significance of such a species under in vivo conditions.
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Affiliation(s)
- Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
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Vianney YM, Preckwinkel P, Mohr S, Weisz K. Quadruplex-Duplex Junction: A High-Affinity Binding Site for Indoloquinoline Ligands. Chemistry 2020; 26:16910-16922. [PMID: 32975874 PMCID: PMC7756412 DOI: 10.1002/chem.202003540] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/21/2020] [Indexed: 12/23/2022]
Abstract
A parallel quadruplex derived from the Myc promoter sequence was extended by a stem-loop duplex at either its 5'- or 3'-terminus to mimic a quadruplex-duplex (Q-D) junction as a potential genomic target. High-resolution structures of the hybrids demonstrate continuous stacking of the duplex on the quadruplex core without significant perturbations. An indoloquinoline ligand carrying an aminoalkyl side chain was shown to bind the Q-D hybrids with a very high affinity in the order Ka ≈107 m-1 irrespective of the duplex location at the quadruplex 3'- or 5'-end. NMR chemical shift perturbations identified the tetrad face of the Q-D junction as specific binding site for the ligand. However, calorimetric analyses revealed significant differences in the thermodynamic profiles upon binding to hybrids with either a duplex extension at the quadruplex 3'- or 5'-terminus. A large enthalpic gain and considerable hydrophobic effects are accompanied by the binding of one ligand to the 3'-Q-D junction, whereas non-hydrophobic entropic contributions favor binding with formation of a 2:1 ligand-quadruplex complex in case of the 5'-Q-D hybrid.
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Affiliation(s)
- Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Pit Preckwinkel
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Swantje Mohr
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
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Haase L, Weisz K. Locked nucleic acid building blocks as versatile tools for advanced G-quadruplex design. Nucleic Acids Res 2020; 48:10555-10566. [PMID: 32890406 PMCID: PMC7544228 DOI: 10.1093/nar/gkaa720] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/24/2020] [Accepted: 08/20/2020] [Indexed: 01/21/2023] Open
Abstract
A hybrid-type G-quadruplex is modified with LNA (locked nucleic acid) and 2′-F-riboguanosine in various combinations at the two syn positions of its third antiparallel G-tract. LNA substitution in the central tetrad causes a complete rearrangement to either a V-loop or antiparallel structure, depending on further modifications at the 5′-neighboring site. In the two distinct structural contexts, LNA-induced stabilization is most effective compared to modifications with other G surrogates, highlighting a potential use of LNA residues for designing not only parallel but various more complex G4 structures. For instance, the conventional V-loop is a structural element strongly favored by an LNA modification at the V-loop 3′-end in contrast with an alternative V-loop, clearly distinguishable by altered conformational properties and base-backbone interactions as shown in a detailed analysis of V-loop structures.
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Affiliation(s)
- Linn Haase
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489 Greifswald, Germany
| | - Klaus Weisz
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489 Greifswald, Germany
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17
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Tang Q, Vianney YM, Weisz K, Grathwol CW, Link A, Bornscheuer UT, Pavlidis IV. Influence of Substrate Binding Residues on the Substrate Scope and Regioselectivity of a Plant
O
‐Methyltransferase against Flavonoids. ChemCatChem 2020. [DOI: 10.1002/cctc.202000471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Qingyun Tang
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17489 Greifswald Germany
| | - Yoanes M. Vianney
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17489 Greifswald Germany
| | - Klaus Weisz
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17489 Greifswald Germany
| | - Christoph W. Grathwol
- Institute of PharmacyUniversity of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Andreas Link
- Institute of PharmacyUniversity of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Uwe T. Bornscheuer
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17489 Greifswald Germany
| | - Ioannis V. Pavlidis
- Dept. of ChemistryUniversity of Crete Voutes University Campus 70013 Heraklion Greece
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18
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Schnarr L, Jana J, Preckwinkel P, Weisz K. Impact of a Snap-Back Loop on Stability and Ligand Binding to a Parallel G-Quadruplex. J Phys Chem B 2020; 124:2778-2787. [DOI: 10.1021/acs.jpcb.0c00700] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lena Schnarr
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Jagannath Jana
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Pit Preckwinkel
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
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19
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Abstract
A DNA G-quadruplex adopting a (3+1) hybrid structure was modified in two adjacent syn positions of the antiparallel strand with anti-favoring 2'-deoxy-2'-fluoro-riboguanosine (F rG) analogues. The two substitutions promoted a structural rearrangement to a topology with the 5'-terminal G residue located in the central tetrad and the two modified residues linked by a V-shaped zero-nucleotide loop. Strikingly, whereas a sugar pucker in the preferred north domain is found for both modified nucleotides, the F rG analogue preceding the V-loop is forced to adopt the unfavored syn conformation in the new quadruplex fold. Apparently, a preferred C3'-endo sugar pucker within the V-loop architecture outweighs the propensity of the F rG analogue to adopt an anti glycosidic conformation. Refolding into a V-loop topology is likewise observed for a sequence modified at corresponding positions with two riboguanosine substitutions. In contrast, 2'-F-arabinoguanosine analogues with their favored south-east sugar conformation do not support formation of the V-loop topology. Examination of known G-quadruplexes with a V-shaped loop highlights the critical role of the sugar conformation for this distinct structural motif.
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Affiliation(s)
- Linn Haase
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Str. 417487GreifswaldGermany
| | - Jonathan Dickerhoff
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Str. 417487GreifswaldGermany
- Present address: Department of Medicinal Chemistry and Molecular PharmacologyCollege of PharmacyPurdue UniversityWest LafayetteIN47907USA
| | - Klaus Weisz
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Str. 417487GreifswaldGermany
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20
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Abstract
The interplay of specific fluoro interactions determines conformational features of G-quadruplexes with two different 2′-fluoro-substituted residues.
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Affiliation(s)
- Linn Haase
- Institut für Biochemie
- Universität Greifswald
- D-17489 Greifswald
- Germany
| | - Klaus Weisz
- Institut für Biochemie
- Universität Greifswald
- D-17489 Greifswald
- Germany
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21
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Purwanto MGM, Weisz K. NMR studies on oligonucleotide - Methylene blue conjugates targeting double-helical nucleic acids. Biophys Chem 2019; 257:106314. [PMID: 31862498 DOI: 10.1016/j.bpc.2019.106314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 11/30/2019] [Accepted: 12/03/2019] [Indexed: 10/25/2022]
Abstract
Methylene blue (MB) - nucleic acid interactions are of considerable interest due to the photosensitizing activity of the dye with potential applications in medicine and biotechnology. Covalent attachment of the MB to an oligonucleotide through a flexible heptamethylene linker enabled a positioning of the dye moiety to specific sites through triplex formation with a target duplex. NMR studies demonstrated interactions of MB with the nucleic acids. In sequences with the MB moiety facing the triplex-duplex junction with an alternating CG duplex overhang next to a T·A·T triple-helical tract, proton resonances experienced severe linebroadening upon MB binding and point to kinetically labile complexes with exchange among different binding modes. For sequences with the MB moiety facing a terminal T·A·T base triad of the triplex tract, structural heterogeneity decreased when compared to a triplex without MB attached to the third strand. Also, the thermal stability of the latter construct increased significantly in the presence of MB, indicating external end stacking as predominant binding mode. Without any obvious disruptions of sequential imino-imino NOE contacts within the triplex and duplex tracts, a most favorable intercalation between T·A·T base triples or CG base pairs is not supported by the present data under our experimental conditions.
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Affiliation(s)
| | - Klaus Weisz
- University of Surabaya, Faculty of Biotechnology, Surabaya, Indonesia; University of Greifswald, Institute of Biochemistry, 17489 Greifswald, Germany.
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22
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Karg B, Mohr S, Weisz K. Duplex‐Guided Refolding into Novel G‐Quadruplex (3+1) Hybrid Conformations. Angew Chem Int Ed Engl 2019; 58:11068-11071. [DOI: 10.1002/anie.201905372] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Beatrice Karg
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
| | - Swantje Mohr
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
| | - Klaus Weisz
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
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23
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Affiliation(s)
- Beatrice Karg
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Deutschland
| | - Swantje Mohr
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Deutschland
| | - Klaus Weisz
- Institut für BiochemieUniversität Greifswald Felix-Hausdorff-Straße 4 17487 Greifswald Deutschland
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24
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Abstract
The ability to control the folding topology of DNA G-quadruplexes allows for rational design of quadruplex-based scaffolds for potential use in various therapeutic and technological applications. By exploiting the distinct conformational properties of some base- and sugar-modified guanosine surrogates, conformational transitions can be induced through their judicious incorporation at specific sites in the quadruplex core. Changes may involve tetrad polarity inversions with conservation of the global fold or complete refolding to new topologies. Reliable predictions relating to low-energy conformers formed upon specific chemical perturbations of the system and the rational design of modified sequences suffer from our still limited understanding of the subtle interplay of various favorable and unfavorable interactions within a particular quadruplex scaffold. However, aided by an increasing number of systematic substitution experiments and high-resolution structures of modified quadruplex variants, critical interactions, in addition to glycosidic bond angle propensities, are starting to emerge as important contributors to modification-driven quadruplex refolding.
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Affiliation(s)
- Linn Haase
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Beatrice Karg
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
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25
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Abstract
The thermodynamic characterization of G4-ligand interactions has shown to be a powerful adjunct to structural information in the rational design and optimization of potent G-quadruplex ligands for use in therapeutics, diagnostics, or other technological applications. Isothermal titration calorimetry (ITC) can resolve energetic contributions to complex formation and constitutes the only available experimental method to directly measure binding enthalpies. A general protocol for using ITC in studies on quadruplex-ligand interactions with details on the experimental setup, data analysis, and potential pitfalls is presented. The methodologies used are illustrated on results obtained from the targeting of a parallel DNA G-quadruplex with a G4-binding indoloquinoline derivative.
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Affiliation(s)
- Andrea Funke
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany.
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26
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Funke A, Weisz K. Thermodynamic signature of indoloquinolines interacting with G-quadruplexes: Impact of ligand side chain. Biochimie 2018; 157:142-148. [PMID: 30481540 DOI: 10.1016/j.biochi.2018.11.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 11/22/2018] [Indexed: 10/27/2022]
Abstract
Binding of indoloquinolines with different aliphatic side chains to a parallel G-quadruplex derived from the MYC promoter sequence was characterized by optical and calorimetric measurements. ITC experiments performed at different temperatures enabled the determination of molar heat capacity changes upon quadruplex binding and a partitioning of the total binding free enthalpy into contributing terms with hydrophobic effects being major driving forces for all derivatives. Whereas affinities increase for indoloquinolines equipped with a long and positively charged side arm, the highest contribution of specific intermolecular interactions anticipated to impart enhanced specificity is found for a ligand with an uncharged ether aliphatic tail. Obtained thermodynamic signatures may considerably aid in the rational selection of ligand side chains for G-quadruplex binders with enhanced affinity or selectivity.
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Affiliation(s)
- Andrea Funke
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17487, Greifswald, Germany.
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27
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Frommer J, Karg B, Weisz K, Müller S. Preparation and characterization of pyrene modified uridine derivatives as potential electron donors in RNA. Org Biomol Chem 2018; 16:7663-7673. [PMID: 30283974 DOI: 10.1039/c8ob02246a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Charge transfer across double stranded DNA was observed for the first time about 20 years ago, and ever since it has been the subject of a large number of studies. RNA has been hardly investigated in this regard, which not least is due to the lack of suitably functionalized ribonucleotide building blocks to serve as electron sources upon incorporation into oligoribonucleotides. We have synthesized two uridine derivatives carrying pyrene or dimethylaminopyrene linked to C5 of the nucleobase. The key to successful synthesis was the adaptation of Suzuki-Miyaura conditions to the coupling of the pyrene moiety with the ribonucleoside. Final decoration of the pyrenylated nucleosides with standard 5'-O- and 2'-O-protecting groups and subsequent 3'-O-phosphitylation delivered the building blocks for incorporation into RNA. Spectroscopic analysis of the two pyrenylated uridines and of the accordingly modified oligonucleotides showed that in particular the dimethyaminopyrene functionalized nucleoside is a promising candidate as an electron source for RNA charge transport studies.
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Affiliation(s)
- Jennifer Frommer
- University of Greifswald, Institute of Biochemistry, Feilx-Hausdorff-Str. 4, 17487 Greifswald, Germany.
| | - Beatrice Karg
- University of Greifswald, Institute of Biochemistry, Feilx-Hausdorff-Str. 4, 17487 Greifswald, Germany.
| | - Klaus Weisz
- University of Greifswald, Institute of Biochemistry, Feilx-Hausdorff-Str. 4, 17487 Greifswald, Germany.
| | - Sabine Müller
- University of Greifswald, Institute of Biochemistry, Feilx-Hausdorff-Str. 4, 17487 Greifswald, Germany.
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28
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Haase L, Dickerhoff J, Weisz K. DNA–RNA Hybrid Quadruplexes Reveal Interactions that Favor RNA Parallel Topologies. Chemistry 2018; 24:15365-15371. [DOI: 10.1002/chem.201803367] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/05/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Linn Haase
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
| | - Jonathan Dickerhoff
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
- Present address: Department of Medicinal Chemistry and Molecular PharmacologyCollege of PharmacyPurdue University West Lafayette IN 47907 USA
| | - Klaus Weisz
- Institute of BiochemistryUniversity of Greifswald Felix-Hausdorff-Str. 4 17487 Greifswald Germany
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29
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Karg B, Weisz K. Loop Length Affects Syn-Anti Conformational Rearrangements in Parallel G-Quadruplexes. Chemistry 2018; 24:10246-10252. [PMID: 29756658 DOI: 10.1002/chem.201801851] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/12/2018] [Indexed: 01/24/2023]
Abstract
A G-quadruplex forming sequence from the MYC promoter region was modified with syn-favoring 8-bromo-2'-deoxyguanosine residues. Depending on the number and position of modifications in the intramolecular parallel G-quadruplex, substitutions with the bromoguanosine analogue at the 5'-tetrad induce conformational rearrangements with concerted all-anti to all-syn transitions for all residues of the modified G-quartet. No unfavorable steric interactions of the C8-substituents in the medium grooves are apparent in the high-resolution structure as determined for a tetrasubstituted MYC quadruplex that exclusively forms the all-syn isomer. In contrast, considerable steric clashes with 5'-phosphate oxygen atoms for those analogues that follow a less flexible 1-nucleotide loop in the native all-anti conformation seem to constitute the major driving force for the tetrad inversion and allow for the rational design of appropriately substituted sequences. Correlations found between the population of species subjected to a tetrad flip and melting temperatures indicate that more effective conformational transitions are compromised by lower thermal stabilities of the modified parallel quadruplexes.
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Affiliation(s)
- Beatrice Karg
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
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30
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Abstract
A (3+1)-hybrid-type G-quadruplex was substituted within its central tetrad by a single 2'-fluoro-modified guanosine. Driven by the anti-favoring nucleoside analogue, a novel quadruplex fold with inversion of a single G-tract and conversion of a propeller loop into a lateral loop emerges. In addition, scalar couplings across hydrogen bonds demonstrate the formation of intra- and inter-residual F⋅⋅⋅H8-C8 pseudo-hydrogen bonds within the modified quadruplexes. Alternative folding can be rationalized by the impact of fluorine on intermediate species on the basis of a kinetic partitioning mechanism. Apparently, chemical or other environmental perturbations are able to redirect folding of a quadruplex, possibly modulating its regulatory role in physiological processes.
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Affiliation(s)
- Jonathan Dickerhoff
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
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31
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Funke A, Karg B, Dickerhoff J, Balke D, Müller S, Weisz K. Ligand-Induced Dimerization of a Truncated Parallel MYC G-Quadruplex. Chembiochem 2018; 19:505-512. [PMID: 29228465 DOI: 10.1002/cbic.201700593] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Indexed: 02/04/2023]
Abstract
Binding of an indoloquinoline derivative with an aminoalkyl side chain to a truncated sequence from the MYC promoter region was studied through isothermal titration calorimetry (ITC). The targeted MYC3 sequence lacks 3'-flanking nucleotides and forms a monomeric parallel quadruplex (G4) with a blunt-ended 3'-outer tetrad under the solution conditions employed. Analysis of ITC isotherms reveals multiple binding equilibria with the initial formation of a 1:2 ligand/quadruplex complex. Evaluation of electrophoretic mobilities as well as NMR spectral data confirm ligand-induced dimerization of MYC3 quadruplexes with the ligand sandwiched between the two 3'-outer tetrads. Additional ligand molecules in excess bind to the 5'-outer tetrads of the sandwich complex. Such a ligand-promoted G4 dimerization may be exploited for the controlled assembly or disassembly of G4 aggregates to expand on present quadruplex-based technologies.
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Affiliation(s)
- Andrea Funke
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Beatrice Karg
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Jonathan Dickerhoff
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Darko Balke
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Sabine Müller
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
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32
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Abstract
A G-quadruplex adopting a (3 + 1)-hybrid structure was substituted at its 5'-tetrad by 2'-deoxy-2'-fluoro-arabinoguanosine (FaraG) analogs. Incorporation of anti-favoring FaraG at syn-positions of the 5'-outer tetrad induced a reversal of the tetrad polarity without noticeably compromising the quadruplex stability. This conformational change is shown to be promoted by nonconventional C-H···F hydrogen bonds acting within the anti-FaraG residues.
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Affiliation(s)
- Jonathan Dickerhoff
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
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33
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Affiliation(s)
- Andrea Funke
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
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34
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Abstract
A human telomere sequence that folds into an intramolecular (3 + 1)-hybrid G-quadruplex was modified by the incorporation of 2'-fluoro-2'-deoxyriboguanosines (FG) into syn positions of its outer tetrad. A circular dichroism and NMR spectral analysis reveals a nearly quantitative switch of the G-tetrad polarity with concerted syn↔anti transitions of all four G residues. These observations follow findings on a FG-substituted (3 + 1)-hybrid quadruplex with a different fold, suggesting a more general propensity of hybrid-type quadruplexes to undergo a tetrad polarity reversal. Two out of the three FG analogs in both modified quadruplexes adopt an S-type sugar pucker, challenging a sole contribution of N-type sugars in enforcing an anti glycosidic torsion angle associated with the tetrad flip. NMR restrained three-dimensional structures of the two substituted quadruplexes reveal a largely conserved overall fold but significant rearrangements of the overhang and loop nucleotides capping the flipped tetrad. Sugar pucker preferences of the FG analogs may be rationalized by different orientations of the fluorine atom and its resistance to be positioned within the narrow groove with its highly negative electrostatic potential and spine of water molecules.
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Affiliation(s)
- Jonathan Dickerhoff
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Linn Haase
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Walter Langel
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
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35
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Buchholz I, Karg B, Dickerhoff J, Sievers-Engler A, Lämmerhofer M, Weisz K. Selective Targeting of G-Quadruplex Structures by a Benzothiazole-Based Binding Motif. Chemistry 2017; 23:5814-5823. [PMID: 28276093 DOI: 10.1002/chem.201700298] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Indexed: 12/28/2022]
Abstract
A benzothiazole derivative was identified as potent ligand for DNA G-quadruplex structures. Fluorescence titrations revealed selective binding to quadruplexes of different topologies including parallel, antiparallel, and (3+1) hybrid structures. The parallel c-MYC sequence was found to constitute the preferred target with dissociation constants in the micromolar range. Binding of the benzothiazole-based ligand to c-MYC was structurally and thermodynamically characterized in detail by employing a comprehensive set of spectroscopic and calorimetric techniques. Job plot analyses and mass spectral data indicate noncooperative ligand binding to form complexes with 1:1 and 2:1 stoichiometries. Whereas stacking interactions are suggested by optical methods, NMR chemical shift perturbations also indicate significant rearrangements of both 5'- and 3'-flanking sequences upon ligand binding. Additional isothermal calorimetry studies yield a thermodynamic profile of the ligand-quadruplex association and reveal enthalpic contributions to be the major driving force for binding. Structural and thermodynamic information obtained in the present work provides the basis for the rational development of benzothiazole derivatives as promising quadruplex binding agents.
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Affiliation(s)
- Ina Buchholz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Beatrice Karg
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Jonathan Dickerhoff
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Adrian Sievers-Engler
- Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Michael Lämmerhofer
- Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
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Abstract
A MYC sequence forming an intramolecular G-quadruplex with a parallel topology was modified by the incorporation of 8-bromoguanosine (BrG) analogues in one of its outer G-tetrads. The propensity of the BrG analogues to adopt a syn glycosidic torsion angle results in an exceptional monomolecular quadruplex conformation featuring a complete flip of one tetrad while keeping a parallel orientation of all G-tracts as shown by circular dichroism and nuclear magnetic resonance spectroscopic studies. When substituting three of the four G-tetrad residues with BrG analogues, two coexisting quadruplex conformational isomers with an all-syn and all-anti outer G-quartet are approximately equally populated in solution. A dynamic interconversion of the two quadruplexes with an exchange rate (kex) of 0.2 s-1 is demonstrated through the observation of exchange crosspeaks in rotating frame Overhauser effect spectroscopy and nuclear Overhauser effect spectroscopy experiments at 50 °C. The kinetic properties suggest disruption of the corresponding outer G-tetrad but not of the whole quadruplex core during the tetrad flip. Conformational syn-anti isomers with homopolar and heteropolar stacking interactions are nearly isoenergetic with a transition enthalpy of 18.2 kJ/mol in favor of the all-syn isomer.
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Affiliation(s)
- Beatrice Karg
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Linn Haase
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Andrea Funke
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Jonathan Dickerhoff
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald , Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany
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Dickerhoff J, Appel B, Müller S, Weisz K. Zuckerseitige Wechselwirkungen in einem DNA-RNA-G-Quadruplex: Hinweise auf sequentielle C−H⋅⋅⋅O-Wasserstoffbrücken als Beitrag zur RNA-Quadruplex-Faltung. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jonathan Dickerhoff
- Institut für Biochemie; Ernst-Moritz-Arndt-Universität Greifswald; Felix-Hausdorff-Str. 4 17487 Greifswald Deutschland
| | - Bettina Appel
- Institut für Biochemie; Ernst-Moritz-Arndt-Universität Greifswald; Felix-Hausdorff-Str. 4 17487 Greifswald Deutschland
| | - Sabine Müller
- Institut für Biochemie; Ernst-Moritz-Arndt-Universität Greifswald; Felix-Hausdorff-Str. 4 17487 Greifswald Deutschland
| | - Klaus Weisz
- Institut für Biochemie; Ernst-Moritz-Arndt-Universität Greifswald; Felix-Hausdorff-Str. 4 17487 Greifswald Deutschland
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38
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Dickerhoff J, Appel B, Müller S, Weisz K. Sugar-Edge Interactions in a DNA-RNA G-Quadruplex: Evidence of Sequential C-H⋅⋅⋅O Hydrogen Bonds Contributing to RNA Quadruplex Folding. Angew Chem Int Ed Engl 2016; 55:15162-15165. [PMID: 27860177 DOI: 10.1002/anie.201608275] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 09/29/2016] [Indexed: 11/11/2022]
Abstract
DNA G-quadruplexes were systematically modified by single riboguanosine (rG) substitutions at anti-dG positions. Circular dichroism and NMR experiments confirmed the conservation of the native quadruplex topology for most of the DNA-RNA hybrid structures. Changes in the C8 NMR chemical shift of guanosines following rG substitution at their 3'-side within the quadruplex core strongly suggest the presence of C8-H⋅⋅⋅O hydrogen-bonding interactions with the O2' position of the C2'-endo ribonucleotide. A geometric analysis of reported high-resolution structures indicates that such interactions are a more general feature in RNA quadruplexes and may contribute to the observed preference for parallel topologies.
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Affiliation(s)
- Jonathan Dickerhoff
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Bettina Appel
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Sabine Müller
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
| | - Klaus Weisz
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487, Greifswald, Germany
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Funke A, Dickerhoff J, Weisz K. Towards the Development of Structure-Selective G-Quadruplex-Binding Indolo[3,2-b
]quinolines. Chemistry 2016; 22:3170-81. [DOI: 10.1002/chem.201504416] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Indexed: 01/24/2023]
Affiliation(s)
- Andrea Funke
- Institute of Biochemistry; Ernst-Moritz-Arndt University Greifswald; Felix-Hausdorff-Strasse 4 17487 Greifswald Germany
| | - Jonathan Dickerhoff
- Institute of Biochemistry; Ernst-Moritz-Arndt University Greifswald; Felix-Hausdorff-Strasse 4 17487 Greifswald Germany
| | - Klaus Weisz
- Institute of Biochemistry; Ernst-Moritz-Arndt University Greifswald; Felix-Hausdorff-Strasse 4 17487 Greifswald Germany
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Karg B, Funke A, Ficht A, Sievers-Engler A, Lämmerhofer M, Weisz K. Molecular Recognition and Visual Detection of G-Quadruplexes by a Dicarbocyanine Dye. Chemistry 2015; 21:13802-11. [DOI: 10.1002/chem.201502118] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Indexed: 11/12/2022]
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Kohls H, Anderson M, Dickerhoff J, Weisz K, Córdova A, Berglund P, Brundiek H, Bornscheuer UT, Höhne M. Selective Access to All Four Diastereomers of a 1,3-Amino Alcohol by Combination of a Keto Reductase- and an Amine Transaminase-Catalysed Reaction. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500214] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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43
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Thomsen M, Tuukkanen A, Dickerhoff J, Palm GJ, Kratzat H, Svergun DI, Weisz K, Bornscheuer UT, Hinrichs W. Structure and catalytic mechanism of the evolutionarily unique bacterial chalcone isomerase. ACTA ACUST UNITED AC 2015; 71:907-17. [PMID: 25849401 DOI: 10.1107/s1399004715001935] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 01/29/2015] [Indexed: 11/10/2022]
Abstract
Flavonoids represent a large class of secondary metabolites produced by plants. These polyphenolic compounds are well known for their antioxidative abilities, are antimicrobial phytoalexins responsible for flower pigmentation to attract pollinators and, in addition to other properties, are also specific bacterial regulators governing the expression of Rhizobium genes involved in root nodulation (Firmin et al., 1986). The bacterial chalcone isomerase (CHI) from Eubacterium ramulus catalyses the first step in a flavanone-degradation pathway by ring opening of (2S)-naringenin to form naringenin chalcone. The structural biology and enzymology of plant CHIs have been well documented, whereas the existence of bacterial CHIs has only recently been elucidated. This first determination of the structure of a bacterial CHI provides detailed structural insights into the key step of the flavonoid-degradation pathway. The active site could be confirmed by co-crystallization with the substrate (2S)-naringenin. The stereochemistry of the proposed mechanism of the isomerase reaction was verified by specific (1)H/(2)H isotope exchange observed by (1)H NMR experiments and was further supported by mutagenesis studies. The active site is shielded by a flexible lid, the varying structure of which could be modelled in different states of the catalytic cycle using small-angle X-ray scattering data together with the crystallographic structures. Comparison of bacterial CHI with the plant enzyme from Medicago sativa reveals that they have unrelated folds, suggesting that the enzyme activity evolved convergently from different ancestor proteins. Despite the lack of any functional relationship, the tertiary structure of the bacterial CHI shows similarities to the ferredoxin-like fold of a chlorite dismutase and the stress-related protein SP1.
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Affiliation(s)
- Maren Thomsen
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
| | - Anne Tuukkanen
- EMBL, c/o DESY, Notkestrasse 85, Gebäude 25A, 22603 Hamburg, Germany
| | - Jonathan Dickerhoff
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
| | - Gottfried J Palm
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
| | - Hanna Kratzat
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
| | - Dmitri I Svergun
- EMBL, c/o DESY, Notkestrasse 85, Gebäude 25A, 22603 Hamburg, Germany
| | - Klaus Weisz
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
| | - Uwe T Bornscheuer
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
| | - Winfried Hinrichs
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489 Greifswald, Germany
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Skalden L, Peters C, Dickerhoff J, Nobili A, Joosten HJ, Weisz K, Höhne M, Bornscheuer UT. Two subtle amino Acid changes in a transaminase substantially enhance or invert enantiopreference in cascade syntheses. Chembiochem 2015; 16:1041-5. [PMID: 25801772 DOI: 10.1002/cbic.201500074] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 11/07/2022]
Abstract
Amine transaminases (ATAs) are powerful enzymes for the stereospecific production of chiral amines. However, the synthesis of amines incorporating more than one stereocenter is still a challenge. We developed a cascade synthesis to access optically active 3-alkyl-substituted chiral amines by combining two asymmetric synthesis steps catalyzed by an enoate reductase and ATAs. The ATA wild type from Vibrio fluvialis showed only modest enantioselectivity (14 % de) in the amination of (S)-3-methylcyclohexanone, the product of the enoate-reductase-catalyzed reaction step. However, by protein engineering we created two variants with substantially improved diastereoselectivities: variant Leu56Val exhibited a higher R selectivity (66 % de) whereas the Leu56Ile substitution caused a switch in enantiopreference to furnish the S-configured diastereomer (70 % de). Addition of 30 % DMSO further improved the selectivity and facilitated the synthesis of (1R,3S)-1-amino-3-methylcyclohexane with 89 % de at 87 % conversion.
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Affiliation(s)
- Lilly Skalden
- Biotechnology and Enzyme Catalysis, Institute of Biochemistry, Felix-Hausdorff-Strasse 4, 17487 Greifswald (Germany)
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Dickerhoff J, Weisz K. Flipping a G-tetrad in a unimolecular quadruplex without affecting its global fold. Angew Chem Int Ed Engl 2015; 54:5588-91. [PMID: 25775974 DOI: 10.1002/anie.201411887] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/22/2015] [Indexed: 11/07/2022]
Abstract
A unimolecular G-quadruplex with a hybrid-type topology and propeller, diagonal, and lateral loops was examined for its ability to undergo structural changes upon specific modifications. Substituting 2'-deoxy-2'-fluoro analogues with a propensity to adopt an anti glycosidic conformation for two or three guanine deoxyribonucleosides in syn positions of the 5'-terminal G-tetrad significantly alters the CD spectral signature of the quadruplex. An NMR analysis reveals a polarity switch of the whole tetrad with glycosidic conformational changes detected for all four guanine nucleosides in the modified sequence. As no additional rearrangement of the overall fold occurs, a novel type of G-quadruplex is formed with guanosines in the four columnar G-tracts lined up in either an all-syn or an all-anti glycosidic conformation.
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Affiliation(s)
- Jonathan Dickerhoff
- Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487 Greifswald (Germany)
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47
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Santos-Aberturas J, Engel J, Dickerhoff J, Dörr M, Rudroff F, Weisz K, Bornscheuer UT. Exploration of the Substrate Promiscuity of Biosynthetic Tailoring Enzymes as a New Source of Structural Diversity for Polyene Macrolide Antifungals. ChemCatChem 2014. [DOI: 10.1002/cctc.201402773] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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48
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Silantyev GA, Filippov OA, Musa S, Gelman D, Belkova NV, Weisz K, Epstein LM, Shubina ES. Conformational Flexibility of Dibenzobarrelene-Based PC(sp3)P Pincer Iridium Hydride Complexes: The Role of Hemilabile Functional Groups and External Coordinating Solvents. Organometallics 2014. [DOI: 10.1021/om500308g] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Gleb A. Silantyev
- A.
N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Oleg A. Filippov
- A.
N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Sanaa Musa
- Institute
of Chemistry, The Hebrew University, Edmond Safra Campus, Givat Ram, 91904 Jerusalem, Israel
| | - Dmitri Gelman
- Institute
of Chemistry, The Hebrew University, Edmond Safra Campus, Givat Ram, 91904 Jerusalem, Israel
| | - Natalia V. Belkova
- A.
N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Klaus Weisz
- Institut
für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Straße
4, 17487 Greifswald, Germany
| | - Lina M. Epstein
- A.
N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Elena S. Shubina
- A.
N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
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49
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Dickerhoff J, Riechert-Krause F, Seifert J, Weisz K. Exploring multiple binding sites of an indoloquinoline in triple-helical DNA: a paradigm for DNA triplex-selective intercalators. Biochimie 2014; 107 Pt B:327-37. [PMID: 25281796 DOI: 10.1016/j.biochi.2014.09.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/23/2014] [Indexed: 01/03/2023]
Abstract
Employing NMR spectroscopic methods preferred binding sites of a triplex-selective indoloquinoline drug were examined with three DNA triplex targets. To directly derive and evaluate number and type of the different sites of interaction, studies were performed on short triple-helical constructs specifically labeled with 3-(15)N thymidine probes. The detection and assignment of several coexisting species was enabled through the observation of slow exchange on the chemical shift timescale between complexes and free triplex. In general, the 5'-triplex-duplex junction constitutes the most favorable intercalation site, in particular when flanked by a TAT base triad. NMR data also revealed two different orientations for the intercalating indoloquinoline drug. Binding affinity significantly decreases with a C(+)GC triad bordering the junction but junction binding is still preferred over intercalation between TAT base triads within the triplex stem. In addition to the intercalation between two uncharged TAT triplets, intercalation between a TAT and a 3'-terminal C(+)GC triplet was also observed, indicating a non-protonated third strand cytosine at the triplex end position.
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Affiliation(s)
- Jonathan Dickerhoff
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Fanny Riechert-Krause
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Jenny Seifert
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany
| | - Klaus Weisz
- Institute of Biochemistry, Ernst-Moritz-Arndt University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany.
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Basílio Janke EM, Weisz K. A TT Dinucleotide with a Nonionic Silyl Backbone: Impact on Conformation and H-Bond Mediated Base Pairing as Studied by Low-Temperature NMR. Z PHYS CHEM 2013. [DOI: 10.1524/zpch.2013.0382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
A TSiT dinucleotide linked through a nonionic diisopropylsilyl backbone has been synthesized and studied for its self-association through base–base recognition together with a free thymidine nucleoside. To characterize hydrogen-bonded associates in more detail, NMR measurements were performed in a freonic solvent at temperatures as low as 113 K in the slow hydrogen bond exchange regime. For the thymidine, TT base pairs with both the 2- and 4-carbonyl engaged in hydrogen bonds to the imino proton were observed. Whereas hydrogen bonds to the O4 acceptor are stronger as evidenced by a more deshielded proton in the hydrogen bridge when compared to hydrogen bonds to the O2 acceptor, the latter is nevertheless slightly favored over O4 in the H-bond formation of TT base pairs. The diisopropylsilyl linkage of the TSiT dinucleotide has no significant impact on the geometry and strength of formed NH–O2 and NH–O4 hydrogen bonds indicating, that the silyl backbone does not compromise the alignment of bases and does not pose any restrictions to the cyclic hydrogen bond formation between thymidines of the two strands. However, NMR results point to an exclusive formation of TSiT duplexes with an antiparallel strand orientation.
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