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Li Z, Huang Y, Hung TI, Sun J, Aispuro D, Chen B, Guevara N, Ji F, Cong X, Zhu L, Wang S, Guo Z, Chang CE, Xue M. MYC-Targeting Inhibitors Generated from a Stereodiversified Bicyclic Peptide Library. J Am Chem Soc 2024; 146:1356-1363. [PMID: 38170904 PMCID: PMC10797614 DOI: 10.1021/jacs.3c09615] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024]
Abstract
Here, we present the second generation of our bicyclic peptide library (NTB), featuring a stereodiversified structure and a simplified construction strategy. We utilized a tandem ring-opening metathesis and ring-closing metathesis reaction (ROM-RCM) to cyclize the linear peptide library in a single step, representing the first reported instance of this reaction being applied to the preparation of macrocyclic peptides. Moreover, the resulting bicyclic peptide can be easily linearized for MS/MS sequencing with a one-step deallylation process. We employed this library to screen against the E363-R378 epitope of MYC and identified several MYC-targeting bicyclic peptides. Subsequent in vitro cell studies demonstrated that one candidate, NT-B2R, effectively suppressed MYC transcription activities and cell proliferation.
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Affiliation(s)
- Zhonghan Li
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Yi Huang
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Ta I Hung
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Jianan Sun
- Environmental
Toxicology Graduate Program, University
of California, Riverside, Riverside, California 92521, United States
| | - Desiree Aispuro
- Environmental
Toxicology Graduate Program, University
of California, Riverside, Riverside, California 92521, United States
| | - Boxi Chen
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Nathan Guevara
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Fei Ji
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Xu Cong
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Lingchao Zhu
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Siwen Wang
- Environmental
Toxicology Graduate Program, University
of California, Riverside, Riverside, California 92521, United States
| | - Zhili Guo
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
| | - Chia-en Chang
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
- Environmental
Toxicology Graduate Program, University
of California, Riverside, Riverside, California 92521, United States
| | - Min Xue
- Department
of Chemistry, University of California,
Riverside, Riverside, California 92521, United States
- Environmental
Toxicology Graduate Program, University
of California, Riverside, Riverside, California 92521, United States
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2
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Abstract
Synthetic receptors have a wide range of potential applications, but it has been difficult to design low molecular weight receptors that bind ligands with high, "proteinlike" affinities. This study uses novel computational methods to understand why it is hard to design a high-affinity receptor and to explore the limits of affinity, with the bioactive peptide RGD as a model ligand. The M2 modeling method is found to yield excellent agreement with experiment for a known RGD receptor and then is used to analyze a series of receptors generated in silico with a de novo design algorithm. Forces driving binding are found to be systematically opposed by proportionate repulsions due to desolvation and entropy. In particular, strong correlations are found between Coulombic attractions and the electrostatic desolvation penalty and between the mean energy change on binding and the cost in configurational entropy. These correlations help explain why it is hard to achieve high affinity. The change in surface area upon binding is found to correlate poorly with affinity within this series. Measures of receptor efficiency are formulated that summarize how effectively a receptor uses surface area, total energy, and Coulombic energy to achieve affinity. Analysis of the computed efficiencies suggests that a low molecular weight receptor can achieve proteinlike affinity. It is also found that macrocyclization of a receptor can, unexpectedly, increase the entropy cost of binding because the macrocyclic structure further restricts ligand motion.
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Affiliation(s)
- Wei Chen
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, Maryland 20850, USA
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3
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Abstract
High macromolecular concentrations, or crowded conditions, have been shown to affect a wide variety of molecular processes, including diffusion, association and dissociation, and protein folding and stability. Here, we model the effect of macromolecular crowding on the internal dynamics of a protein, HIV-1 protease, using Brownian dynamics simulations. HIV-1 protease possesses a pair of flaps which are postulated to open in the early stages of its catalytic mechanism. Compared to low concentrations, close-packed concentrations of repulsive crowding agents are found to significantly reduce the fraction of time that the protease flaps are open. Macromolecular crowding is likely to have a major effect on in vivo enzyme activity, and may play an important regulatory role in the viral life cycle.
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Affiliation(s)
- David D.L. Minh
- Department of Chemistry and Biochemistry, Center for Theoretical Biological Physics, University of California at San Diego, La Jolla California 92093-0365,
| | - Chia-en Chang
- Department of Chemistry and Biochemistry, Center for Theoretical Biological Physics, University of California at San Diego, La Jolla California 92093-0365,
| | - Joanna Trylska
- Interdisciplinary Centre for Mathematical and Computational Modeling, Warsaw University, 02-106 Warsaw, Poland
| | - Valentina Tozzini
- NEST Scuola Normale Superiore, Piazza dei Cavalieri, 7 I-56126 Pisa, Italy
| | - J. Andrew McCammon
- Department of Chemistry and Biochemistry, Center for Theoretical Biological Physics, University of California at San Diego, La Jolla California 92093-0365,
- Department of Pharmacology, Howard Hughes Medical Institute, University of California at San Diego, La Jolla California 92093-0365
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Tozzini V, Trylska J, Chang CE, McCammon JA. Flap opening dynamics in HIV-1 protease explored with a coarse-grained model. J Struct Biol 2006; 157:606-15. [PMID: 17029846 DOI: 10.1016/j.jsb.2006.08.005] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 07/20/2006] [Accepted: 08/03/2006] [Indexed: 11/18/2022]
Abstract
We present a one-bead coarse-grained model that enables dynamical simulations of proteins on the time scale of tens of microseconds. The parameterization of the force field includes accurate conformational terms that allow for fast and reliable exploration of the configurational space. The model is applied to the dynamics of flap opening in HIV-1 protease. The experimental structure of the recently crystallized semi-open conformation of HIV-1 protease is well reproduced in the simulation, which supports the accuracy of our model. Thanks to very long simulations and extensive sampling of opening and closing events, we also investigate the thermodynamics and kinetics of the opening process. We have shown that the effect of the solvent slows down the dynamics to the experimentally observed time scales. The model is found to be reliable for application to substrate docking simulations, which are currently in progress.
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Affiliation(s)
- Valentina Tozzini
- NEST-INFM-CNR Scuola Normale Superiore, Piazza dei Cavalieri, 7 I-56126 Pisa, Italy.
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DeJong ES, Chang CE, Gilson MK, Marino JP. Proflavine acts as a Rev inhibitor by targeting the high-affinity Rev binding site of the Rev responsive element of HIV-1. Biochemistry 2003; 42:8035-46. [PMID: 12834355 DOI: 10.1021/bi034252z] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rev is an essential regulatory HIV-1 protein that binds the Rev responsive element (RRE) within the env gene of the HIV-1 RNA genome, activating the switch between viral latency and active viral replication. Previously, we have shown that selective incorporation of the fluorescent probe 2-aminopurine (2-AP) into a truncated form of the RRE sequence (RRE-IIB) allowed the binding of an arginine-rich peptide derived from Rev and aminoglycosides to be characterized directly by fluorescence methods. Using these fluorescence and nuclear magnetic resonance (NMR) methods, proflavine has been identified, through a limited screen of selected small heterocyclic compounds, as a specific and high-affinity RRE-IIB binder which inhibits the interaction of the Rev peptide with RRE-IIB. Direct and competitive 2-AP fluorescence binding assays reveal that there are at least two classes of proflavine binding sites on RRE-IIB: a high-affinity site that competes with the Rev peptide for binding to RRE-IIB (K(D) approximately 0.1 +/- 0.05 microM) and a weaker binding site(s) (K(D) approximately 1.1 +/- 0.05 microM). Titrations of RRE-IIB with proflavine, monitored using (1)H NMR, demonstrate that the high-affinity proflavine binding interaction occurs with a 2:1 (proflavine:RRE-IIB) stoichiometry, and NOEs observed in the NOESY spectrum of the 2:1 proflavine.RRE-IIB complex indicate that the two proflavine molecules bind specifically and close to each other within a single binding site. NOESY data further indicate that formation of the 2:1 proflavine.RRE-IIB complex stabilizes base pairing and stacking within the internal purine-rich bulge of RRE-IIB in a manner analogous to what has been observed in the Rev peptide.RRE-IIB complex. The observation that proflavine competes with Rev for binding to RRE-IIB by binding as a dimer to a single high-affinity site opens the possibility for rational drug design based on linking and modifying it and related compounds.
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MESH Headings
- 2-Aminopurine/chemistry
- Anti-Infective Agents, Local/pharmacology
- Antimetabolites/chemistry
- Binding Sites/drug effects
- Binding, Competitive/genetics
- Dimerization
- Fluorescence
- Gene Products, rev/antagonists & inhibitors
- Gene Products, rev/metabolism
- Genes, env/drug effects
- HIV-1
- Humans
- Nuclear Magnetic Resonance, Biomolecular
- Nucleic Acid Conformation
- Proflavine/pharmacology
- Protein Binding/genetics
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Spectrometry, Fluorescence
- Thermodynamics
- rev Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Eric S DeJong
- Center for Advanced Research in Biotechnology of the University of Maryland Biotechnology Institute and the National Institute for Standards and Technology, 9600 Gudelsky Drive, Rockville, Maryland 20850, USA
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Chang CE, Eo HG, Lee YS, Chung SK, Shin JS, Lah YK, Park CW, Jung JT, Huh JW, Lee SM. Human intravenous immunoglobulin preparation and virus inactivation by pasteurization and solvent detergent treatment. Prep Biochem Biotechnol 2000; 30:177-97. [PMID: 10919559 DOI: 10.1080/10826060008544957] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [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: 10/22/2022]
Abstract
Human intravenous immunoglobulin (IVIG) solutions were prepared by two different methods and compared to each other. The crude immunoglobulin fraction obtained from Cohn-Oncley fractionation of plasma was further purified and subjected to virus inactivation, either by polyethylene glycol precipitation and pasteurization at 60 degrees C for 10 hours, or by ion exchange chromatography and solvent/detergent treatment. The final preparations, formulated in 5% immunoglobulin solutions were characterized by in vitro analyses of biochemical and biological properties and compared with the samples of other manufacturer's IVIG solution products. The critical properties evaluated in this study were purity, molecular intactness, and the biological functions such as Fc function and anticomplementary activity. Virus inactivation and removal by processing steps and by deliberate virucidal steps, as described above, were tested on various human pathogenic viruses, such as human immunodeficiency and experimental model viruses. The tested viruses were successfully inactivated and removed. We conclude that the intravenous immunoglobulins prepared by two different methods, as described above, provide an equivalent viral safety and quality.
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Affiliation(s)
- C E Chang
- Korea Green Cross Corporation, Yongin, Kyunggi-do
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7
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Wang CR, Liu MF, Jeng GW, Lin HP, Hsieh RP, Chuang CY, Chang CE. Autoantibodies and related immunity of leprosy patients from leprosarium in Taiwan. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi 1992; 25:181-8. [PMID: 1342003] [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] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Autoantibodies and related immunological examinations were measured in 60 leprosy patients from a leprosarium in Taiwan. Thirty-one lepromatous type, 24 tuberculoid type and 5 borderline type patients were identified. The measured autoantibodies included antinuclear antibodies, anti-nDNA, anti-cardiolipin and rheumatoid factor. Serum protein electrophoresis and immunofixation were also performed to detect the monoclonal and polyclonal status of immunoglobulins. Circulating immune complex and complements were also quantitated. Delayed type skin tests were performed during patients' visits. A higher frequency of autoantibodies, especially the antinuclear antibodies and anticardiolipin antibodies, were detected in lepromatous type patients. Higher levels of circulating immune complex and frequency of polyclonal and monoclonal gammopathy were also noted in lepromatous type patients. Anergy skin tests were only noted in lepromatous type patients. It was concluded that the more impared cell-mediated immunity in leprosy patients, with lepromatous type in particular, the greater the production of autoantibodies.
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Affiliation(s)
- C R Wang
- Department of Internal Medicine, National Taiwan University Hospital, R.O.C
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8
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Shih YH, Huang ZJ, Chang CE. Color pattern-reversal visual evoked potential in eyes with ocular hypertension and primary open-angle glaucoma. Doc Ophthalmol 1991; 77:193-200. [PMID: 1760968 DOI: 10.1007/bf00161367] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [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: 12/28/2022]
Abstract
Color pattern-reversal visual evoked potential testing was performed in 99 normal eyes, 27 eyes with ocular hypertension and 30 eyes with primary open-angle glaucoma with the use of black-white, black-red and black-blue color checkerboard stimuli. The P1 wave peak time and amplitude of the eyes with ocular hypertension and glaucoma were significantly different from those of age-similar normal eyes, especially on the black-red and black-blue checkerboards (p less than 0.001). The differences between the ocular hypertensive and glaucomatous eyes were of less significance. The P1 peak time difference between black-white and black-red checkerboards may serve as an important parameter in the early diagnosis of glaucoma.
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Affiliation(s)
- Y H Shih
- Beijing Institute of Ophthalmology, China
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Suo J, Chang CE, Lin TP, Heifets LB. Minimal inhibitory concentrations of isoniazid, rifampin, ethambutol, and streptomycin against Mycobacterium tuberculosis strains isolated before treatment of patients in Taiwan. Am Rev Respir Dis 1988; 138:999-1001. [PMID: 3144210 DOI: 10.1164/ajrccm/138.4.999] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Minimal inhibitory concentrations (MICs) of isoniazid (INH), rifampin (RMP), ethambutol (EMB), and streptomycin (SM) for susceptible "wild" M. tuberculosis strains isolated from Taiwanese patients were within the limits previously reported for strains isolated in the United States. The highest agar-determined MICs (in 7H10 and 7H11 agar) corresponded well with the critical concentrations established for these media. The highest MICs found radiometrically in 7H12 broth were significantly lower than the critical concentrations proposed for this medium. On the basis of an evaluation of the highest broth-determined MICs found in this and in the previous study (1), we suggest that the following MICs, when determined radiometrically, should be used as breakpoints to classify the strain as "susceptible": for INH, 0.1 microgram/ml or less; for RMP, 0.5 microgram/ml or less; for EMB, 4.0 micrograms/ml or less; for SM, 2.0 micrograms/ml or less.
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Affiliation(s)
- J Suo
- Taiwan Provincial Tuberculosis Control Bureau, Taipei, Republic of China
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10
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Huang RM, Suo J, Lee JJ, Lin TP, Chang CE. [Lower lung field tuberculosis]. Taiwan Yi Xue Hui Za Zhi 1987; 86:993-6. [PMID: 3694171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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11
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Yang SP, Luh KT, Lin TP, Chang CE. [The criteria for the termination of short-term tuberculosis chemotherapy]. Taiwan Yi Xue Hui Za Zhi 1986; 85:919-31. [PMID: 3469304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Yang SP, Luh KT, lin TP, Chang CE. [Short course chemotherapy in pulmonary tuberculosis on individual basis--final report]. Kekkaku 1986; 61:75-83. [PMID: 3712929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Abstract
The proteins and sodium in human source blood plasma are segregated and concentrated on freezing, particularly in plasma that is frozen slowly in a large container. The temperature and the concentration gradients at the freezing front induce a convection in the liquid phase and thus play the primary role in the segregation of proteins and sodium in the frozen mass. Unidirectional freezing, where the freezing front moves against gravity, minimizes segregation because the density gradient-induced convection is minimized at the solid-liquid interface. Microscopic observation of the freezing front of the plasma indicates that ice crystals are the primary solid formed. Their shape is generally irregular, and they become highly dendritic as the freezing rate increases. Apparently, the liquid phase at the freezing front is trapped between the ice crystals; it then undergoes a complex secondary freezing process at a lower temperature behind the primary freezing front of the ice crystals.
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Ko YC, Chang CE, Liu SS, Hu HT. [Epidemiological study of PCB poisoning (author's transl)]. Taiwan Yi Xue Hui Za Zhi 1981; 80:406-17. [PMID: 6796645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Yang SP, Luh KT, Luan HW, Chang CE. Short-term intensive initial chemotherapy for pulmonary tuberculosis--preliminary report--can the duration of TB treatment be even shorter? Kekkaku 1978; 53:25-37. [PMID: 633698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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