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Pett L, Kiakos K, Satam V, Patil P, Laughlin-Toth S, Gregory M, Bowerman M, Olson K, Savagian M, Lee M, Lee M, Wilson WD, Hochhauser D, Hartley JA. Modulation of topoisomerase IIα expression and chemosensitivity through targeted inhibition of NF-Y:DNA binding by a diamino p-anisyl-benzimidazole (Hx) polyamide. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2017; 1860:617-629. [PMID: 27750031 PMCID: PMC5757371 DOI: 10.1016/j.bbagrm.2016.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/11/2016] [Accepted: 10/12/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Sequence specific polyamide HxIP 1, targeted to the inverted CCAAT Box 2 (ICB2) on the topoisomerase IIα (topo IIα) promoter can inhibit NF-Y binding, re-induce gene expression and increase sensitivity to etoposide. To enhance biological activity, diamino-containing derivatives (HxI*P 2 and HxIP* 3) were synthesised incorporating an alkyl amino group at the N1-heterocyclic position of the imidazole/pyrrole. METHODS DNase I footprinting was used to evaluate DNA binding of the diamino Hx-polyamides, and their ability to disrupt the NF-Y:ICB2 interaction assessed using EMSAs. Topo IIα mRNA (RT-PCR) and protein (Immunoblotting) levels were measured following 18h polyamide treatment of confluent A549 cells. γH2AX was used as a marker for etoposide-induced DNA damage after pre-treatment with HxIP* 3 and cell viability was measured using Cell-Titer Glo®. RESULTS Introduction of the N1-alkyl amino group reduced selectivity for the target sequence 5'-TACGAT-3' on the topo IIα promoter, but increased DNA binding affinity. Confocal microscopy revealed both fluorescent diamino polyamides localised in the nucleus, yet HxI*P 2 was unable to disrupt the NF-Y:ICB2 interaction and showed no effect against the downregulation of topo IIα. In contrast, inhibition of NF-Y binding by HxIP* 3 stimulated dose-dependent (0.1-2μM) re-induction of topo IIα and potentiated cytotoxicity of topo II poisons by enhancing DNA damage. CONCLUSIONS Polyamide functionalisation at the N1-position offers a design strategy to improve drug-like properties. Dicationic HxIP* 3 increased topo IIα expression and chemosensitivity to topo II-targeting agents. GENERAL SIGNIFICANCE Pharmacological modulation of topo IIα expression has the potential to enhance cellular sensitivity to clinically-used anticancer therapeutics. This article is part of a Special Issue entitled: Nuclear Factor Y in Development and Disease, edited by Prof. Roberto Mantovani.
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Affiliation(s)
- Luke Pett
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK
| | - Konstantinos Kiakos
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK
| | - Vijay Satam
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Pravin Patil
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Sarah Laughlin-Toth
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Matthew Gregory
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Michael Bowerman
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Kevin Olson
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Mia Savagian
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Megan Lee
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Moses Lee
- Department of Chemistry, Hope College, Holland, MI 49423, United States; Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Daniel Hochhauser
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK
| | - John A Hartley
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London, WC1E 6BT, UK.
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Satam V, Babu B, Patil P, Brien KA, Olson K, Savagian M, Lee M, Mepham A, Jobe LB, Bingham JP, Pett L, Wang S, Ferrara M, Bruce CD, Wilson WD, Lee M, Hartley JA, Kiakos K. AzaHx, a novel fluorescent, DNA minor groove and G·C recognition element: Synthesis and DNA binding properties of a p-anisyl-4-aza-benzimidazole-pyrrole-imidazole (azaHx-PI) polyamide. Bioorg Med Chem Lett 2015; 25:3681-5. [PMID: 26122210 DOI: 10.1016/j.bmcl.2015.06.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 06/09/2015] [Accepted: 06/11/2015] [Indexed: 11/30/2022]
Abstract
The design, synthesis, and DNA binding properties of azaHx-PI or p-anisyl-4-aza-benzimidazole-pyrrole-imidazole (5) are described. AzaHx, 2-(p-anisyl)-4-aza-benzimidazole-5-carboxamide, is a novel, fluorescent DNA recognition element, derived from Hoechst 33258 to recognize G·C base pairs. Supported by theoretical data, the results from DNase I footprinting, CD, ΔT(M), and SPR studies provided evidence that an azaHx/IP pairing, formed from antiparallel stacking of two azaHx-PI molecules in a side-by-side manner in the minor groove, selectively recognized a C-G doublet. AzaHx-PI was found to target 5'-ACGCGT-3', the Mlu1 Cell Cycle Box (MCB) promoter sequence with specificity and significant affinity (K(eq) 4.0±0.2×10(7) M(-1)).
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Affiliation(s)
- Vijay Satam
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Balaji Babu
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Pravin Patil
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Kimberly A Brien
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Kevin Olson
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Mia Savagian
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Megan Lee
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Andrew Mepham
- Department of Chemistry, Hope College, Holland, MI 49423, United States
| | - Laura Beth Jobe
- Department of Chemistry, Erskine College, Due West, SC 29639, United States
| | - John P Bingham
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London WC1E 6BT, UK
| | - Luke Pett
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London WC1E 6BT, UK
| | - Shuo Wang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Maddi Ferrara
- Department of Chemistry, John Carroll University, University Heights, OH 44118, United States
| | - Chrystal D Bruce
- Department of Chemistry, John Carroll University, University Heights, OH 44118, United States
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States
| | - Moses Lee
- Department of Chemistry, Hope College, Holland, MI 49423, United States; Department of Chemistry, Georgia State University, Atlanta, GA 30303, United States.
| | - John A Hartley
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London WC1E 6BT, UK
| | - Konstantinos Kiakos
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London WC1E 6BT, UK
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Bruce CD, Ferrara MM, Manka JL, Davis ZS, Register J. Dynamic hydrogen bonding and DNA flexibility in minor groove binders: molecular dynamics simulation of the polyamide f-ImPyIm bound to the Mlu1 (MCB) sequence 5'-ACGCGT-3' in 2:1 motif. J Mol Recognit 2015; 28:325-37. [PMID: 25711379 DOI: 10.1002/jmr.2448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 10/10/2014] [Accepted: 11/09/2014] [Indexed: 12/28/2022]
Abstract
Molecular dynamics simulations of the DNA 10-mer 5'-CCACGCGTGG-3' alone and complexed with the formamido-imidazole-pyrrole-imidazole (f-ImPyIm) polyamide minor groove binder in a 2:1 fashion were conducted for 50 ns using the pbsc0 parameters within the AMBER 12 software package. The change in DNA structure upon binding of f-ImPyIm was evaluated via minor groove width and depth, base pair parameters of Slide, Twist, Roll, Stretch, Stagger, Opening, Propeller, and x-displacement, dihedral angle distributions of ζ, ε, α, and γ determined using the Curves+ software program, and hydrogen bond formation. The dynamic hydrogen bonding between the f-ImPyIm and its cognate DNA sequence was compared to the static image used to predict sequence recognition by polyamide minor groove binders. Many of the predicted hydrogen bonds were present in less than 50% of the simulation; however, persistent hydrogen bonds between G5/15 and the formamido group of f-ImPyIm were observed. It was determined that the DNA is wider in the Complex than without the polyamide binder; however, there is flexibility in this particular sequence, even in the presence of the f-ImPyIm as evidenced by the range of minor groove widths the DNA exhibits and the dynamics of the hydrogen bonding that binds the two f-ImPyIm ions to the minor groove. The Complex consisting of the DNA and the 2 f-ImPyIm binders shows slight fraying of the 5' end of the 10-mer at the end of the simulation, but the portion of the oligomer responsible for recognition and binding is stable throughout the simulation. Several structural changes in the Complex indicate that minor groove binders may have a more active role in inhibiting transcription than just preventing binding of important transcription factors.
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Affiliation(s)
- Chrystal D Bruce
- Department of Chemistry, John Carroll University, 1 John Carroll Boulevard, University Heights, OH, 44118, USA
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Ramos JP, Babu B, Chavda S, Liu Y, Plaunt A, Ferguson A, Savagian M, Lee M, Tzou S, Lin S, Kiakos K, Wang S, Lee M, Hartley JA, Wilson WD. Affinity and kinetic modulation of polyamide-DNA interactions by N-modification of the heterocycles. Biopolymers 2013; 99:497-507. [PMID: 23712486 PMCID: PMC3872963 DOI: 10.1002/bip.22205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/31/2012] [Accepted: 01/02/2013] [Indexed: 12/27/2022]
Abstract
Synthetic N-methyl imidazole and N-pyrrole containing polyamides (PAs) that can form "stacked" dimers can be programmed to target and bind to specific DNA sequences and control gene expression. To accomplish this goal, the development of PAs with lower molecular mass which allows for the molecules to rapidly penetrate cells and localize in the nucleus, along with increased water solubility, while maintaining DNA binding sequence specificity and high binding affinity is key. To meet these challenges, six novel f-ImPy*Im PA derivatives that contain different orthogonally positioned moieties were designed to target 5'-ACGCGT-3'. The synthesis and biophysical characterization of six f-ImPy*Im were determined by CD, ΔTM, DNase I footprinting, SPR, and ITC studies, and were compared with those of their parent compound, f-ImPyIm. The results gave evidence for the minor groove binding and selectivity of PAs 1 and 6 for the cognate sequence 5'-ACGCGT-3', and with strong affinity, Keq = 2.8 × 10(8) M(-1) and Keq = 6.2 × 10(7) M(-1), respectively. The six novel PAs presented in this study demonstrated increased water solubility, while maintaining low molecular mass, sequence specificity, and binding affinity, addressing key issues in therapeutic development.
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Affiliation(s)
- Joseph P. Ramos
- Department of Chemistry, Georgia State University, Atlanta, GA 30303
| | - Balaji Babu
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Sameer Chavda
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Yang Liu
- Department of Chemistry, Georgia State University, Atlanta, GA 30303
| | - Adam Plaunt
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Amanda Ferguson
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Mia Savagian
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Megan Lee
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Samuel Tzou
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - Shicai Lin
- Cancer Research, UK Drug–DNA Interactions Research Group, UCL Cancer Institute, Paul O’ Gorman Building, 72 Huntley Street, London WCIE 6BT, UK
| | - Konstantinos Kiakos
- Cancer Research, UK Drug–DNA Interactions Research Group, UCL Cancer Institute, Paul O’ Gorman Building, 72 Huntley Street, London WCIE 6BT, UK
| | - Shuo Wang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303
| | - Moses Lee
- Department of Chemistry and the Division of Natural and Applied Sciences, Hope College, MI 49423
| | - John A. Hartley
- Cancer Research, UK Drug–DNA Interactions Research Group, UCL Cancer Institute, Paul O’ Gorman Building, 72 Huntley Street, London WCIE 6BT, UK
| | - W. David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303
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5
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Chavda S, Babu B, Patil P, Plaunt A, Ferguson A, Lee M, Tzou S, Sjoholm R, Rice T, Mackay H, Ramos J, Wang S, Lin S, Kiakos K, Wilson WD, Hartley JA, Lee M. Design, synthesis, and DNA binding characteristics of a group of orthogonally positioned diamino, N-formamido, pyrrole- and imidazole-containing polyamides. Bioorg Med Chem 2013; 21:3907-18. [PMID: 23647824 DOI: 10.1016/j.bmc.2013.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/26/2013] [Accepted: 04/02/2013] [Indexed: 02/08/2023]
Abstract
Orthogonally positioned diamino/dicationic polyamides (PAs) have good water solubility and enhanced binding affinity, whilst retaining DNA minor groove and sequence specificity compared to their monoamino/monocationic counterparts. The synthesis and DNA binding properties of the following diamino PAs: f-IPI (3a), f-IPP (4), f-PIP (5), and f-PPP (6) are described. P denotes the site where a 1-propylamino group is attached to the N1-position of the heterocycle. Binding of the diamino PAs to DNA was assessed by DNase I footprinting, thermal denaturation, circular dichroism titration, biosensor surface plasmon resonance (SPR), and isothermal titration calorimetry (ITC) studies. According to SPR studies, f-IPI (3a) bound more strongly (K(eq)=2.4×10(8) M(-1)) and with comparable sequence selectivity to its cognate sequence 5'-ACGCGT-3' when compared to its monoamino analog f-IPI (1). The binding of f-IPI (3a) to 5'-ACGCGT-3' via the stacked dimer motif was balanced between enthalpy and entropy, and that was quite different from the enthalpy-driven binding of its monoamino parent f-IPI (1). f-IPP (4) also bound more strongly to its cognate sequence 5'-ATGCAT-3' (K(eq)=7.4×10(6) M(-1)) via the side-by-side stacked motif than its monoamino analog f-IPP (2a). Although f-PPP (6) bound via a 1:1 motif, it bound strongly to its cognate sequence 5'-AAATTT-3' (K(eq)=4.8×10(7) M(-1)), 15-times higher than the binding of its monoamino analog f-PPP (2c), albeit f-PPP bound via the stacked motif. Finally, f-PIP (5) bound to its target sequence 5'-ATCGAT-3' as a stacked dimer and it has the lowest affinity among the diamino PAs tested (Keq <1×10(5) M(-1)). This was about two times lower in affinity than the binding of its monoamino analog f-PIP (2b). The results further demonstrated that the 'core rules' of DNA recognition by monoamino PAs also apply to their diamino analogs. Specifically, PAs that contain a stacked IP core structure bind most strongly (highest binding constants) to their cognate GC doublet, followed by the binding of PAs with a stacked PP structure to two degenerate AT base pairs, and finally the binding of PAs with a PI core to their cognate CG doublet.
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Affiliation(s)
- Sameer Chavda
- Division of Natural and Applied Sciences and Department of Chemistry, Hope College, Holland, MI 49423, USA
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6
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Blackledge MS, Melander C. Programmable DNA-binding small molecules. Bioorg Med Chem 2013; 21:6101-14. [PMID: 23665141 DOI: 10.1016/j.bmc.2013.04.023] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/29/2013] [Accepted: 04/05/2013] [Indexed: 10/26/2022]
Abstract
Aberrant gene expression is responsible for a myriad of human diseases from infectious diseases to cancer. Precise regulation of these genes via specific interactions with the DNA double helix could pave the way for novel therapeutics. Pyrrole-imidazole polyamides are small molecules capable of binding to pre-determined DNA sequences up to 16 base pairs with affinity and specificity comparable to natural transcription factors. In the three decades since their development, great strides have been made relating to synthetic accessibility and improved sequence specificity and binding affinity. This perspective presents a brief history of early seminal developments in the field and highlights recent reports of the utility of polyamides as both genetic modulators and molecular probes.
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Affiliation(s)
- Meghan S Blackledge
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8024, United States
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Bashkin JK, Aston K, Ramos JP, Koeller KJ, Nanjunda R, He G, Dupureur CM, David Wilson W. Promoter scanning of the human COX-2 gene with 8-ring polyamides: unexpected weakening of polyamide-DNA binding and selectivity by replacing an internal N-Me-pyrrole with β-alanine. Biochimie 2012; 95:271-9. [PMID: 23023196 DOI: 10.1016/j.biochi.2012.09.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 09/18/2012] [Indexed: 12/16/2022]
Abstract
Rules for polyamide-DNA recognition have proved invaluable for the design of sequence-selective DNA binding agents in cell-free systems. However, these rules are not fully transferrable to predicting activity in cells, tissues or animals, and additional refinements to our understanding of DNA recognition would help biomedical studies. Similar complexities are encountered when using internal β-alanines as polyamide building blocks in place of N-methylpyrrole; β-alanines were introduced in polyamide designs to maintain good hydrogen bonding registry with the target DNA, especially for long polyamides or those with several GC bp (P.B. Dervan, A.R. Urbach, Essays Contemp. Chem. (2001) 327-339). Thus, to clarify important subtleties of molecular recognition, we studied the effects of replacing a single pyrrole with β-alanine in 8-ring polyamides designed against the Ets-1 transcription factor. Replacement of a single internal N-methylpyrrole with β-alanine to generate a β/Im pairing in two 8-ring polyamides causes a decrease in DNA binding affinity by two orders of magnitude and decreases DNA binding selectivity, contrary to expectations based on the literature. Measurements were made by fluorescence spectroscopy, quantitative DNA footprinting and surface plasmon resonance, with these vastly different techniques showing excellent agreement. Furthermore, results were validated for a range of DNA substrates from small hairpins to long dsDNA sequences. Docking studies helped show that β-alanine does not make efficient hydrophobic contacts with the rest of the polyamide or nearby DNA, in contrast to pyrrole. These results help refine design principles and expectations for polyamide-DNA recognition.
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Affiliation(s)
- James K Bashkin
- Department of Chemistry & Biochemistry, Center for Nanoscience, University of Missouri-St. Louis, One University Blvd., St. Louis, MO 63121, USA.
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Synthesis and DNA binding properties of 1-(3-aminopropyl)-imidazole-containing triamide f-Im∗PyIm: A novel diamino polyamide designed to target 5′-ACGCGT-3′. Bioorg Med Chem Lett 2012; 22:5898-902. [DOI: 10.1016/j.bmcl.2012.07.071] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/20/2012] [Indexed: 12/27/2022]
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Satam V, Babu B, Chavda S, Savagian M, Sjoholm R, Tzou S, Ramos J, Liu Y, Kiakos K, Lin S, David Wilson W, Hartley JA, Lee M. Novel diamino imidazole and pyrrole-containing polyamides: Synthesis and DNA binding studies of mono- and diamino-phenyl-ImPy*Im polyamides designed to target 5'-ACGCGT-3'. Bioorg Med Chem 2011; 20:693-701. [PMID: 22222156 DOI: 10.1016/j.bmc.2011.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/04/2011] [Accepted: 12/06/2011] [Indexed: 12/28/2022]
Abstract
Pyrrole- and imidazole-containing polyamides are widely investigated as DNA sequence selective binding agents that have potential use as gene control agents. The key challenges that must be overcome to realize this goal is the development of polyamides with low molar mass so the molecules can readily diffuse into cells and concentrate in the nucleus. In addition, the molecules must have appreciable water solubility, bind DNA sequence specifically, and with high affinity. It is on this basis that the orthogonally positioned diamino/dicationic polyamide Ph-ImPy*Im 5 was designed to target the sequence 5'-ACGCGT-3'. Py* denotes the pyrrole unit that contains a N-substituted aminopropyl pendant group. The DNA binding properties of diamino polyamide 5 were determined using a number of techniques including CD, ΔT(M), DNase I footprinting, SPR and ITC studies. The effects of the second amino moiety in Py* on DNA binding affinity over its monoamino counterpart Ph-ImPyIm 3 were assessed by conducting DNA binding studies of 3 in parallel with 5. The results confirmed the minor groove binding and selectivity of both polyamides for the cognate sequence 5'-ACGCGT-3'. The diamino/dicationic polyamide 5 showed enhanced binding affinity and higher solubility in aqueous media over its monoamino/monocationic counterpart Ph-ImPyIm 3. The binding constant of 5, determined from SPR studies, was found to be 1.5 × 10(7)M(-1), which is ∼3 times higher than that for its monoamino analog 3 (4.8 × 10(6)M(-1)). The affinity of 5 is now approaching that of the parent compound f-ImPyIm 1 and its diamino equivalent 4. The advantages of the design of diamino polyamide 5 over 1 and 4 are its sequence specificity and the ease of synthesis compared to the N-terminus pyrrole analog 2.
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Affiliation(s)
- Vijay Satam
- Division of Natural and Applied Sciences, Department of Chemistry, Hope College, 35 East, 12th Street, Holland, MI 49423, USA
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