1
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Marunde MR, Fuchs HA, Burg JM, Popova IK, Vaidya A, Hall NW, Weinzapfel EN, Meiners MJ, Watson R, Gillespie ZB, Taylor HF, Mukhsinova L, Onuoha UC, Howard SA, Novitzky K, McAnarney ET, Krajewski K, Cowles MW, Cheek MA, Sun ZW, Venters BJ, Keogh MC, Musselman CA. Nucleosome conformation dictates the histone code. eLife 2024; 13:e78866. [PMID: 38319148 PMCID: PMC10876215 DOI: 10.7554/elife.78866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 02/05/2024] [Indexed: 02/07/2024] Open
Abstract
Histone post-translational modifications (PTMs) play a critical role in chromatin regulation. It has been proposed that these PTMs form localized 'codes' that are read by specialized regions (reader domains) in chromatin-associated proteins (CAPs) to regulate downstream function. Substantial effort has been made to define [CAP: histone PTM] specificities, and thus decipher the histone code and guide epigenetic therapies. However, this has largely been done using the reductive approach of isolated reader domains and histone peptides, which cannot account for any higher-order factors. Here, we show that the [BPTF PHD finger and bromodomain: histone PTM] interaction is dependent on nucleosome context. The tandem reader selectively associates with nucleosomal H3K4me3 and H3K14ac or H3K18ac, a combinatorial engagement that despite being in cis is not predicted by peptides. This in vitro specificity of the BPTF tandem reader for PTM-defined nucleosomes is recapitulated in a cellular context. We propose that regulatable histone tail accessibility and its impact on the binding potential of reader domains necessitates we refine the 'histone code' concept and interrogate it at the nucleosome level.
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Affiliation(s)
| | - Harrison A Fuchs
- Department of Biochemistry, University of Iowa Carver College of MedicineAuroraUnited States
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Krzysztof Krajewski
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel HillChapel HillUnited States
| | | | | | | | | | | | - Catherine A Musselman
- Department of Biochemistry, University of Iowa Carver College of MedicineAuroraUnited States
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical CampusAuroraUnited States
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2
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Zahid H, Costello JP, Li Y, Kimbrough JR, Actis M, Rankovic Z, Yan Q, Pomerantz WCK. Design of Class I/IV Bromodomain-Targeting Degraders for Chromatin Remodeling Complexes. ACS Chem Biol 2023; 18:1278-1293. [PMID: 37260298 PMCID: PMC10698694 DOI: 10.1021/acschembio.2c00902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Targeted protein degradation is an emerging technology that can be used for modulating the activity of epigenetic protein targets. Among bromodomain-containing proteins, a number of degraders for the BET family have been developed, while non-BET bromodomains remain underexplored. Several of these proteins are subunits in chromatin remodeling complexes often associated with oncogenic roles. Here, we describe the design of class I (BPTF and CECR2) and IV (BRD9) bromodomain-targeting degraders based on two scaffolds derived from pyridazinone and pyrimidine-based heterocycles. We evaluate various exit vectors and linkers to identify analogues that demonstrate selectivity within these families. We further use an in-cell NanoBRET assay to demonstrate that these heterobifunctional molecules are cell-permeable, form ternary complexes, and can degrade nanoluciferase-bromodomain fusions. As a first example of a CECR2 degrader, we observe that our pyrimidine-based analogues degrade endogenous CECR2 while showing a smaller effect on BPTF levels. The pyridazinone-based compounds did not degrade BPTF when observed through Western blotting, further supporting a more challenging target for degradation and a goal for future optimization.
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Affiliation(s)
- Huda Zahid
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Jeff P Costello
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Yao Li
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut 06520, United States
| | - Jennifer R Kimbrough
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Marisa Actis
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, United States
| | - Zoran Rankovic
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, United States
| | - Qin Yan
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut 06520, United States
- Yale Cancer Center, Yale School of Medicine, New Haven, Connecticut 06520, United States
| | - William C K Pomerantz
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street SE, Minneapolis, Minnesota 55455, United States
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3
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Herchenröther A, Wunderlich TM, Lan J, Hake SB. Spotlight on histone H2A variants: From B to X to Z. Semin Cell Dev Biol 2022; 135:3-12. [PMID: 35365397 DOI: 10.1016/j.semcdb.2022.03.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 12/30/2022]
Abstract
Chromatin, the functional organization of DNA with histone proteins in eukaryotic nuclei, is the tightly-regulated template for several biological processes, such as transcription, replication, DNA damage repair, chromosome stability and sister chromatid segregation. In order to achieve a reversible control of local chromatin structure and DNA accessibility, various interconnected mechanisms have evolved. One of such processes includes the deposition of functionally-diverse variants of histone proteins into nucleosomes, the building blocks of chromatin. Among core histones, the family of H2A histone variants exhibits the largest number of members and highest sequence-divergence. In this short review, we report and discuss recent discoveries concerning the biological functions of the animal histone variants H2A.B, H2A.X and H2A.Z and how dysregulation or mutation of the latter impacts the development of disease.
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Affiliation(s)
| | - Tim M Wunderlich
- Institute for Genetics, Justus Liebig University, 35390 Giessen, Germany
| | - Jie Lan
- Institute for Genetics, Justus Liebig University, 35390 Giessen, Germany.
| | - Sandra B Hake
- Institute for Genetics, Justus Liebig University, 35390 Giessen, Germany.
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4
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Cui H, Divakaran A, Hoell ZJ, Ellingson MO, Scholtz CR, Zahid H, Johnson JA, Griffith EC, Gee CT, Lee AL, Khanal S, Shi K, Aihara H, Shah VH, Lee RE, Harki DA, Pomerantz WCK. A Structure-based Design Approach for Generating High Affinity BRD4 D1-Selective Chemical Probes. J Med Chem 2022; 65:2342-2360. [PMID: 35007061 DOI: 10.1021/acs.jmedchem.1c01779] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Chemical probes for epigenetic proteins are essential tools for dissecting the molecular mechanisms for gene regulation and therapeutic development. The bromodomain and extra-terminal (BET) proteins are master transcriptional regulators. Despite promising therapeutic targets, selective small molecule inhibitors for a single bromodomain remain an unmet goal due to their high sequence similarity. Here, we address this challenge via a structure-activity relationship study using 1,4,5-trisubstituted imidazoles against the BRD4 N-terminal bromodomain (D1). Leading compounds 26 and 30 have 15 and 18 nM affinity against BRD4 D1 and over 500-fold selectivity against BRD2 D1 and BRD4 D2 via ITC. Broader BET selectivity was confirmed by fluorescence anisotropy, thermal shift, and CETSA. Despite BRD4 engagement, BRD4 D1 inhibition was unable to reduce c-Myc expression at low concentration in multiple myeloma cells. Conversely, for inflammation, IL-8 and chemokine downregulation were observed. These results provide new design rules for selective inhibitors of an individual BET bromodomain.
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Affiliation(s)
- Huarui Cui
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Anand Divakaran
- Department of Medicinal Chemistry, University of Minnesota, 2231 Sixth Street SE, Minneapolis, Minnesota 55455, United States
| | - Zachariah J Hoell
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Mikael O Ellingson
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Cole R Scholtz
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Huda Zahid
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Jorden A Johnson
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Elizabeth C Griffith
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS1000, Memphis, Tennessee 38105, United States
| | - Clifford T Gee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS1000, Memphis, Tennessee 38105, United States
| | - Amani L Lee
- GI Research Unit, Guggenheim 1034 Mayo Clinic, 200 First Street SW Rochester, Minnesota 55902, United States
| | - Shalil Khanal
- GI Research Unit, Guggenheim 1034 Mayo Clinic, 200 First Street SW Rochester, Minnesota 55902, United States
| | - Ke Shi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Vijay H Shah
- GI Research Unit, Guggenheim 1034 Mayo Clinic, 200 First Street SW Rochester, Minnesota 55902, United States
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS1000, Memphis, Tennessee 38105, United States
| | - Daniel A Harki
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.,Department of Medicinal Chemistry, University of Minnesota, 2231 Sixth Street SE, Minneapolis, Minnesota 55455, United States
| | - William C K Pomerantz
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.,Department of Medicinal Chemistry, University of Minnesota, 2231 Sixth Street SE, Minneapolis, Minnesota 55455, United States
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5
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Colino-Sanguino Y, Clark SJ, Valdes-Mora F. The H2A.Z-nuclesome code in mammals: emerging functions. Trends Genet 2021; 38:273-289. [PMID: 34702577 DOI: 10.1016/j.tig.2021.10.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022]
Abstract
H2A.Z is a histone variant that provides specific structural and docking-side properties to the nucleosome, resulting in diverse and specialised molecular and cellular functions. In this review, we discuss the latest studies uncovering new functional aspects of mammalian H2A.Z in gene transcription, including pausing and elongation of RNA polymerase II (RNAPII) and enhancer activity; DNA repair; DNA replication; and 3D chromatin structure. We also review the recently described role of H2A.Z in embryonic development, cell differentiation, neurodevelopment, and brain function. In conclusion, our cumulative knowledge of H2A.Z over the past 40 years, in combination with the implementation of novel molecular technologies, is unravelling an unexpected and complex role of histone variants in gene regulation and disease.
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Affiliation(s)
- Yolanda Colino-Sanguino
- Cancer Epigenetics Biology and Therapeutics, Precision Medicine Theme, Children's Cancer Institute, Sydney, NSW, Australia; School of Children and Women Health, University of NSW Sydney, Sydney, NSW, Australia.
| | - Susan J Clark
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia; St. Vincent's Clinical School, University of NSW Sydney, Sydney, NSW, Australia
| | - Fatima Valdes-Mora
- Cancer Epigenetics Biology and Therapeutics, Precision Medicine Theme, Children's Cancer Institute, Sydney, NSW, Australia; School of Children and Women Health, University of NSW Sydney, Sydney, NSW, Australia.
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6
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Buchholz CR, Pomerantz WCK. 19F NMR viewed through two different lenses: ligand-observed and protein-observed 19F NMR applications for fragment-based drug discovery. RSC Chem Biol 2021; 2:1312-1330. [PMID: 34704040 PMCID: PMC8496043 DOI: 10.1039/d1cb00085c] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/07/2021] [Indexed: 12/28/2022] Open
Abstract
19F NMR has emerged as a powerful tool in drug discovery, particularly in fragment-based screens. The favorable magnetic resonance properties of the fluorine-19 nucleus, the general absence of fluorine in biological settings, and its ready incorporation into both small molecules and biopolymers, has enabled multiple applications of 19F NMR using labeled small molecules and proteins in biophysical, biochemical, and cellular experiments. This review will cover developments in ligand-observed and protein-observed 19F NMR experiments tailored towards drug discovery with a focus on fragment screening. We also cover the key advances that have furthered the field in recent years, including quantitative, structural, and in-cell methodologies. Several case studies are described for each application to highlight areas for innovation and to further catalyze new NMR developments for using this versatile nucleus.
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Affiliation(s)
- Caroline R Buchholz
- Department of Medicinal Chemistry, University of Minnesota 308 Harvard Street SE Minneapolis Minnesota 55455 USA
| | - William C K Pomerantz
- Department of Medicinal Chemistry, University of Minnesota 308 Harvard Street SE Minneapolis Minnesota 55455 USA
- Department of Chemistry, University of Minnesota 207 Pleasant St. SE Minneapolis Minnesota 55455 USA
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7
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Zahid H, Olson NM, Pomerantz WCK. Opportunity knocks for uncovering the new function of an understudied nucleosome remodeling complex member, the bromodomain PHD finger transcription factor, BPTF. Curr Opin Chem Biol 2021; 63:57-67. [PMID: 33706239 PMCID: PMC8384639 DOI: 10.1016/j.cbpa.2021.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/25/2021] [Accepted: 02/01/2021] [Indexed: 12/27/2022]
Abstract
Nucleosome remodeling provides access to genomic DNA for recruitment of the transcriptional machinery to mediate gene expression. The aberrant function of nucleosome remodeling complexes has been correlated to human cancer, making them emerging therapeutic targets. The bromodomain PHD finger transcription factor, BPTF, is the largest member of the human nucleosome remodeling factor NURF. Over the last five years, BPTF has become increasingly identified as a protumorigenic factor, prompting investigations into the molecular mechanisms associated with BPTF function. Despite a druggable bromodomain, small molecule discovery is at an early stage. Here we highlight recent investigations into the biology being discovered for BPTF, chemical biology approaches used to study its function, and small molecule inhibitors being designed as future chemical probes and therapeutics.
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Affiliation(s)
- Huda Zahid
- 207Pleasant St. SE, Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Noelle M Olson
- 207Pleasant St. SE, Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA
| | - William C K Pomerantz
- 207Pleasant St. SE, Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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8
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Boyson SP, Gao C, Quinn K, Boyd J, Paculova H, Frietze S, Glass KC. Functional Roles of Bromodomain Proteins in Cancer. Cancers (Basel) 2021; 13:3606. [PMID: 34298819 PMCID: PMC8303718 DOI: 10.3390/cancers13143606] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/09/2021] [Accepted: 07/09/2021] [Indexed: 12/31/2022] Open
Abstract
Histone acetylation is generally associated with an open chromatin configuration that facilitates many cellular processes including gene transcription, DNA repair, and DNA replication. Aberrant levels of histone lysine acetylation are associated with the development of cancer. Bromodomains represent a family of structurally well-characterized effector domains that recognize acetylated lysines in chromatin. As part of their fundamental reader activity, bromodomain-containing proteins play versatile roles in epigenetic regulation, and additional functional modules are often present in the same protein, or through the assembly of larger enzymatic complexes. Dysregulated gene expression, chromosomal translocations, and/or mutations in bromodomain-containing proteins have been correlated with poor patient outcomes in cancer. Thus, bromodomains have emerged as a highly tractable class of epigenetic targets due to their well-defined structural domains, and the increasing ease of designing or screening for molecules that modulate the reading process. Recent developments in pharmacological agents that target specific bromodomains has helped to understand the diverse mechanisms that bromodomains play with their interaction partners in a variety of chromatin processes, and provide the promise of applying bromodomain inhibitors into the clinical field of cancer treatment. In this review, we explore the expression and protein interactome profiles of bromodomain-containing proteins and discuss them in terms of functional groups. Furthermore, we highlight our current understanding of the roles of bromodomain-containing proteins in cancer, as well as emerging strategies to specifically target bromodomains, including combination therapies using bromodomain inhibitors alongside traditional therapeutic approaches designed to re-program tumorigenesis and metastasis.
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Affiliation(s)
- Samuel P. Boyson
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA;
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA;
| | - Cong Gao
- Department of Biomedical and Health Sciences, University of Vermont, Burlington, VT 05405, USA; (C.G.); (J.B.); (H.P.)
| | - Kathleen Quinn
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA;
- Department of Biomedical and Health Sciences, University of Vermont, Burlington, VT 05405, USA; (C.G.); (J.B.); (H.P.)
| | - Joseph Boyd
- Department of Biomedical and Health Sciences, University of Vermont, Burlington, VT 05405, USA; (C.G.); (J.B.); (H.P.)
| | - Hana Paculova
- Department of Biomedical and Health Sciences, University of Vermont, Burlington, VT 05405, USA; (C.G.); (J.B.); (H.P.)
| | - Seth Frietze
- Department of Biomedical and Health Sciences, University of Vermont, Burlington, VT 05405, USA; (C.G.); (J.B.); (H.P.)
- University of Vermont Cancer Center, Burlington, VT 05405, USA
| | - Karen C. Glass
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Colchester, VT 05446, USA;
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA;
- University of Vermont Cancer Center, Burlington, VT 05405, USA
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9
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Patel K, Solomon PD, Walshe JL, Low JKK, Mackay JP. The bromodomains of BET family proteins can recognize diacetylated histone H2A.Z. Protein Sci 2020; 30:464-476. [PMID: 33247496 DOI: 10.1002/pro.4006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/21/2020] [Accepted: 11/24/2020] [Indexed: 02/02/2023]
Abstract
Chemical modifications of histone tails influence genome accessibility and the transcriptional state of eukaryotic cells. Lysine acetylation is one of the most common modifications and acetyllysine-binding bromodomains (BDs) provide a means for acetyllysine marks to be translated into meaningful cellular responses. Here, we have investigated the mechanism underlying the reported association between the Bromodomain and Extra Terminal (BET) family of BD proteins and the essential histone variant H2A.Z. We use NMR spectroscopy to demonstrate a physical interaction between the N-terminal tail of H2A.Z and the BDs of BRD2, BRD3, and BRD4, and show that the interaction is dependent on lysine acetylation in H2A.Z. The BDs preferentially engage a diacetylated H2A.Z-K4acK7ac motif that is reminiscent of sequences found in other biologically important BET BD target proteins, including histones and transcription factors. A H2A.Z-K7acK11ac motif can also bind BET BDs-with a preference for the second BD of each protein. Chemical shift perturbation mapping of the interactions, together with an X-ray crystal structure of BRD2-BD1 bound to H2A.Z-K4acK7ac, shows that H2A.Z binds the canonical AcK binding pocket of the BDs. This mechanism mirrors the conserved binding mode that is unique to the BET BDs, in which two acetylation marks are read simultaneously by a single BD. Our findings provide structural corroboration of biochemical and cell biological data that link H2A.Z and BET-family proteins, suggesting that the function of H2A.Z is enacted through interactions with these chromatin readers.
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Affiliation(s)
- Karishma Patel
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Paul D Solomon
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - James L Walshe
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia.,Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | - Jason K K Low
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Joel P Mackay
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
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10
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Kalra P, McGraw L, Kimbrough JR, Pandey AK, Solberg J, Cui H, Divakaran A, John K, Hawkinson JE, Pomerantz WCK. Quantifying the Selectivity of Protein-Protein and Small Molecule Interactions with Fluorinated Tandem Bromodomain Reader Proteins. ACS Chem Biol 2020; 15:3038-3049. [PMID: 33138352 PMCID: PMC8185897 DOI: 10.1021/acschembio.0c00720] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multidomain bromodomain-containing proteins regulate gene expression via chromatin binding, interactions with the transcriptional machinery, and by recruiting enzymatic activity. Selective inhibition of members of the bromodomain and extra-terminal (BET) family is important to understand their role in disease and gene regulation, although due to the similar binding sites of BET bromodomains, selective inhibitor discovery has been challenging. To support the bromodomain inhibitor discovery process, here we report the first application of protein-observed fluorine (PrOF) NMR to the tandem bromodomains of BRD4 and BRDT to quantify the selectivity of their interactions with acetylated histones as well as small molecules. We further determine the selectivity profile of a new class of ligands, 1,4-acylthiazepanes, and find them to have ≥3-10-fold selectivity for the C-terminal bromodomain of both BRD4 and BRDT. Given the speed and lower protein concentration required over traditional protein-observed NMR methods, we envision that these fluorinated tandem proteins may find use in fragment screening and evaluating nucleosome and transcription factor interactions.
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Affiliation(s)
- Prakriti Kalra
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Logan McGraw
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Jennifer R Kimbrough
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Anil K Pandey
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Jonathan Solberg
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
| | - Huarui Cui
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
| | - Anand Divakaran
- Department of Medicinal Chemistry, University of Minnesota, 2231 Sixth St. SE, Minneapolis, Minnesota 55455, United States
| | - Kristen John
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
| | - Jon E Hawkinson
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
- Department of Medicinal Chemistry, University of Minnesota, 2231 Sixth St. SE, Minneapolis, Minnesota 55455, United States
| | - William C K Pomerantz
- Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States
- Department of Medicinal Chemistry, University of Minnesota, 2231 Sixth St. SE, Minneapolis, Minnesota 55455, United States
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11
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Combined Protein- and Ligand-Observed NMR Workflow to Screen Fragment Cocktails against Multiple Proteins: A Case Study Using Bromodomains. Molecules 2020; 25:molecules25173949. [PMID: 32872491 PMCID: PMC7504435 DOI: 10.3390/molecules25173949] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022] Open
Abstract
As fragment-based drug discovery has become mainstream, there has been an increase in various screening methodologies. Protein-observed 19F (PrOF) NMR and 1H CPMG NMR are two fragment screening assays that have complementary advantages. Here, we sought to combine these two NMR-based assays into a new screening workflow. This combination of protein- and ligand-observed experiments allows for a time- and resource-efficient multiplexed screen of mixtures of fragments and proteins. PrOF NMR is first used to screen mixtures against two proteins. Hit mixtures for each protein are identified then deconvoluted using 1H CPMG NMR. We demonstrate the benefit of this fragment screening method by conducting the first reported fragment screens against the bromodomains of BPTF and Plasmodium falciparum (Pf) GCN5 using 467 3D-enriched fragments. The hit rates were 6%, 5% and 4% for fragments binding BPTF, PfGCN5, and fragments binding both proteins, respectively. Select hits were characterized, revealing a broad range of affinities from low µM to mM dissociation constants. Follow-up experiments supported a low-affinity second binding site on PfGCN5. This approach can be used to bias fragment screens towards more selective hits at the onset of inhibitor development in a resource- and time-efficient manner.
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