1
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Zhao X, Liu H, Zhang JC, Cai J. Helical sulfonyl-γ-AApeptides for the inhibition of HIV-1 fusion and HIF-1α signaling. RSC Med Chem 2024; 15:1418-1423. [PMID: 38784464 PMCID: PMC11110726 DOI: 10.1039/d4md00110a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 03/19/2024] [Indexed: 05/25/2024] Open
Abstract
Synthetic helical peptidic foldamers show promising applications in chemical biology and biomedical sciences by mimicking protein helical segments. Sulfonyl-γ-AApeptide helices developed by our group exhibit good chemodiversity, predictable folding structures, proteolytic resistance, favorable cell permeability, and enhanced bioavailability. Herein, in this minireview, we highlight two recent examples of homogeneous left-handed sulfonyl-γ-AApeptide helices to modulate protein-protein interactions (PPIs). One is sulfonyl-γ-AApeptides as anti-HIV-1 fusion inhibitors mimicking the helical C-terminal heptad repeat (CHR), which show excellent anti-HIV-1 activities through tight binding with the N-terminal heptad repeat (NHR) and inhibiting the formation of the 6-helical bundle (HB) structure. Another example is helical sulfonyl-γ-AApeptides disrupting hypoxia-inducible factor 1α (HIF-1α) and p300 PPI, thus selectively inhibiting the relevant signaling cascade. We hope these findings could help to elucidate the principles of the structural design of sulfonyl-γ-AApeptides and inspire their future applications in PPI modulations.
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Affiliation(s)
- Xue Zhao
- Department of Chemistry, University of South Florida Tampa FL 33620 USA
| | - Heng Liu
- Department of Chemistry, University of South Florida Tampa FL 33620 USA
| | - Justin C Zhang
- Department of Chemistry, University of South Florida Tampa FL 33620 USA
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida Tampa FL 33620 USA
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2
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Do VQ, Seo YS, Park JM, Yu J, Duong MTH, Nakai J, Kim SK, Ahn HC, Lee MY. A mixture of chloromethylisothiazolinone and methylisothiazolinone impairs rat vascular smooth muscle by depleting thiols and thereby elevating cytosolic Zn 2+ and generating reactive oxygen species. Arch Toxicol 2020; 95:541-556. [PMID: 33074372 DOI: 10.1007/s00204-020-02930-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 10/08/2020] [Indexed: 12/26/2022]
Abstract
Chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) are biocidal preservatives and the active ingredients in Kathon CG, which contains ca. 1.5% mixture of CMIT and MIT at a ratio of 3:1 (CMIT/MIT). CMIT/MIT was misused as humidifier disinfectant products, which caused serious health problems in Korea. Here, the vascular effects of CMIT/MIT were investigated to evaluate claims of putative cardiovascular toxicity observed in humidifier disinfectant users. CMIT/MIT did not affect the basal tension of the rat thoracic aorta up to 2.5 μg/mL in myograph experiments. Instead, pretreatment with CMIT/MIT impaired phenylephrine- or 5-hydroxytryptamine-induced vasoconstriction in a range of 0.5-2.5 μg/mL, which was largely irreversible and not recovered by washing out the CMIT/MIT. Similarly, the application of CMIT/MIT to pre-contracted aorta caused a gradual loss of tension. In primary cultured vascular smooth muscle cells (VSMCs), CMIT/MIT caused thiol depletion, which in turn led to cytosolic Zn2+ elevation and reactive oxygen species (ROS) formation. CMIT/MIT-induced shrinkage, detachment, and lysis of VSMCs depending on the concentration and the treatment time. All events induced by CMIT/MIT were prevented by a thiol donor N-acetylcysteine (NAC). Cytolysis could be inhibited by a Zn2+ chelator TPEN and a superoxide scavenger TEMPOL, whereas they did not affect shrinkage and detachment. In accordance with these results, CMIT/MIT-exposed aortas exhibited dissociation and collapse of tissue in histology analysis. Taken together, CMIT/MIT causes functional impairment and tissue damage to blood vessels by depleting thiol and thereby elevating cytosolic Zn2+ and generating ROS. Therefore, exposure to CMIT/MIT in consumer products may be a risk factor for cardiovascular disorders.
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Affiliation(s)
- Van Quan Do
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Yoon-Seok Seo
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Jung-Min Park
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Jieun Yu
- College of Pharmacy, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Men Thi Hoai Duong
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Junichi Nakai
- Graduate School of Dentistry, Tohoku University, Miyagi, 980-8575, Japan
| | - Sang-Kyum Kim
- College of Pharmacy, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Hee-Chul Ahn
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Moo-Yeol Lee
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea.
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3
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Li Z, You Q, Zhang X. Small-Molecule Modulators of the Hypoxia-Inducible Factor Pathway: Development and Therapeutic Applications. J Med Chem 2019; 62:5725-5749. [DOI: 10.1021/acs.jmedchem.8b01596] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Zhihong Li
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Chemistry, School of Science, China Pharmaceutical University, Nanjing 211198, China
| | - Qidong You
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
| | - Xiaojin Zhang
- State Key Laboratory of Natural Medicines and Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, China
- Department of Chemistry, School of Science, China Pharmaceutical University, Nanjing 211198, China
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4
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Shelat NY, Parhi S, Ostermeier M. Development of a cancer-marker activated enzymatic switch from the herpes simplex virus thymidine kinase. Protein Eng Des Sel 2017; 30:95-103. [PMID: 27986921 PMCID: PMC6080848 DOI: 10.1093/protein/gzw067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/14/2016] [Accepted: 11/21/2016] [Indexed: 01/05/2023] Open
Abstract
Discovery of new cancer biomarkers and advances in targeted gene delivery mechanisms have made gene-directed enzyme prodrug therapy (GDEPT) an attractive method for treating cancer. Recent focus has been placed on increasing target specificity of gene delivery systems and reducing toxicity in non-cancer cells in order to make GDEPT viable. To help address this challenge, we have developed an enzymatic switch that confers higher prodrug toxicity in the presence of a cancer marker. The enzymatic switch was derived from the herpes simplex virus thymidine kinase (HSV-TK) fused to the CH1 domain of the p300 protein. The CH1 domain binds to the C-terminal transactivation domain (C-TAD) of the cancer marker hypoxia inducible factor 1α. The switch was developed using a directed evolution approach that evaluated a large library of HSV-TK/CH1 fusions using a negative selection for azidothymidine (AZT) toxicity and a positive selection for dT phosphorylation. The identified switch, dubbed TICKLE (Trigger-Induced Cell-Killing Lethal-Enzyme), confers a 4-fold increase in AZT toxicity in the presence of C-TAD. The broad substrate specificity exhibited by HSV-TK makes TICKLE an appealing prospect for testing in medical imaging and cancer therapy, while establishing a foundation for further engineering of nucleoside kinase protein switches.
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Affiliation(s)
- Nirav Y Shelat
- Chemical Biology Interface Graduate Program, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Sidhartha Parhi
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Marc Ostermeier
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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5
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Ding L, Yang M, Zhao T, Lv G. Roles of p300 and cyclic adenosine monophosphate response element binding protein in high glucose-induced hypoxia-inducible factor 1α inactivation under hypoxic conditions. J Diabetes Investig 2017; 8:277-285. [PMID: 27808477 PMCID: PMC5415468 DOI: 10.1111/jdi.12592] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 10/05/2016] [Accepted: 10/30/2016] [Indexed: 12/19/2022] Open
Abstract
Aims/Introduction Given the high prevalence of diabetes and burn injuries worldwide, it is essential to dissect the underlying mechanism of delayed burn wound healing in diabetes patients, especially the high glucose‐induced hypoxia‐inducible factor 1 (HIF‐1)‐mediated transcription defects. Materials and Methods Human umbilical vein endothelial cells were cultured with low or high concentrations of glucose. HIF‐1α‐induced vascular endothelial growth factor (VEGF) transcription was measured by luciferase assay. Immunofluorescence staining was carried out to visualize cyclic adenosine monophosphate response element binding protein (CREB) localization. Immunoprecipitation was carried out to characterize the association between HIF‐1α/p300/CREB. To test whether p300, CREB or p300+CREB co‐overexpression was sufficient to rescue the HIF‐1‐mediated transcription defect after high glucose exposure, p300, CREB or p300+CREB co‐overexpression were engineered, and VEGF expression was quantified. Finally, in vitro angiogenesis assay was carried out to test whether the high glucose‐induced angiogenesis defect is rescuable by p300 and CREB co‐overexpression. Results Chronic high glucose treatment resulted in impaired HIF‐1‐induced VEGF transcription and CREB exclusion from the nucleus. P300 or CREB overexpression alone cannot rescue high glucose‐induced HIF‐1α transcription defects. In contrast, co‐overexpression of p300 and CREB dramatically ameliorated high glucose‐induced impairment of HIF‐1‐mediated VEGF transcription, as well as in vitro angiogenesis. Finally, we showed that co‐overexpression of p300 and CREB rectifies the dissociation of HIF‐1α‐p300‐CREB protein complex in chronic high glucose‐treated cells. Conclusion Both p300 and CREB are required for the function integrity of HIF‐1α transcription machinery and subsequent angiogenesis, suggesting future studies to improve burn wound healing might be directed to optimization of the interaction between p300, CREB and HIF‐1α.
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Affiliation(s)
- Lingtao Ding
- Department of Burn and Plastic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi, Jiangsu Province, China.,Department of Plastic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Minlie Yang
- Department of Burn and Plastic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi, Jiangsu Province, China
| | - Tianlan Zhao
- Department of Plastic Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Guozhong Lv
- Department of Burn and Plastic Surgery, The Third Affiliated Hospital of Nantong University, Wuxi, Jiangsu Province, China
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6
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Eo Y, Shim M, Phuong TNT, Hoa PP, Ahn DR, Ahn HC. NMR-based Fragment Screening of Inhibitors Against p300 CH1 and HIF-1α CTAD Interaction. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Yumi Eo
- Department of Pharmacy; Dongguk University; Seoul 10324 Republic of Korea
| | - Myungbo Shim
- Department of Pharmacy; Dongguk University; Seoul 10324 Republic of Korea
| | | | - Phuong Pham Hoa
- Department of Pharmacy; Dongguk University; Seoul 10324 Republic of Korea
| | - Dae-Ro Ahn
- The Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology; Seoul 02792 Republic of Korea
| | - Hee-Chul Ahn
- Department of Pharmacy; Dongguk University; Seoul 10324 Republic of Korea
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7
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El-Araby AM, Fouad AA, Hanbal AM, Abdelwahab SM, Qassem OM, El-Araby ME. Epigenetic Pathways of Oncogenic Viruses: Therapeutic Promises. Arch Pharm (Weinheim) 2016; 349:73-90. [PMID: 26754591 DOI: 10.1002/ardp.201500375] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/30/2015] [Accepted: 12/04/2015] [Indexed: 01/19/2023]
Abstract
Cancerous transformation comprises different events that are both genetic and epigenetic. The ultimate goal for such events is to maintain cell survival and proliferation. This transformation occurs as a consequence of different features such as environmental and genetic factors, as well as some types of infection. Many viral infections are considered to be causative agents of a number of different malignancies. To convert normal cells into cancerous cells, oncogenic viruses must function at the epigenetic level to communicate with their host cells. Oncogenic viruses encode certain epigenetic factors that lead to the immortality and proliferation of infected cells. The epigenetic effectors produced by oncogenic viruses constitute appealing targets to prevent and treat malignant diseases caused by these viruses. In this review, we highlight the importance of epigenetic reprogramming for virus-induced oncogenesis, with special emphasis on viral epigenetic oncoproteins as therapeutic targets. The discovery of molecular components that target epigenetic pathways, especially viral factors, is also discussed.
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Affiliation(s)
- Amr M El-Araby
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | | | - Amr M Hanbal
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | | | - Omar M Qassem
- Faculty of Pharmacy, Ain Shams University, Abbasia, Cairo, Egypt
| | - Moustafa E El-Araby
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanya, Jeddah, Saudi Arabia.,Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Helwan University, Cairo, Egypt
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8
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Chan STS, Patel PR, Ransom TR, Henrich CJ, McKee TC, Goey AKL, Cook KM, Figg WD, McMahon JB, Schnermann MJ, Gustafson KR. Structural Elucidation and Synthesis of Eudistidine A: An Unusual Polycyclic Marine Alkaloid that Blocks Interaction of the Protein Binding Domains of p300 and HIF-1α. J Am Chem Soc 2015; 137:5569-75. [PMID: 25892103 PMCID: PMC6318789 DOI: 10.1021/jacs.5b02156] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Low oxygen environments are a hallmark of solid tumors, and transcription of many hypoxia-responsive genes needed for survival under these conditions is regulated by the transcription factor HIF-1 (hypoxia-inducible factor 1). Activation of HIF-1 requires binding of its α-subunit (HIF-1α) to the transcriptional coactivator protein p300. Inhibition of the p300/HIF-1α interaction can suppress HIF-1 activity. A screen for inhibitors of the protein binding domains of p300 (CH1) and HIF-1α (C-TAD) identified an extract of the marine ascidian Eudistoma sp. as active. Novel heterocyclic alkaloids eudistidines A (1) and B (2) were isolated from the extract, and their structures assigned by spectroscopic analyses. They contain an unprecedented tetracyclic core composed of two pyrimidine rings fused with an imidazole ring. Eudistidine A (1) was synthesized in a concise four-step sequence featuring a condensation/cyclization reaction cascade between 4-(2-aminophenyl)pyrimidin-2-amine (3) and 4-methoxy-phenylglyoxal (4), while eudistidine B (2) was synthesized in a similar fashion with glyoxylic acid (5) in place of 4. Naturally occurring eudistidine A (1) effectively inhibited CH1/C-TAD binding with an IC50 of 75 μM, and synthetic 1 had similar activity. The eudistidine A (1) scaffold, which can be synthesized in a concise, scalable manner, may provide potential therapeutic lead compounds or molecular probes to study p300/HIF-1α interactions and the role these proteins play in tumor response to low oxygen conditions. The unique structural scaffolds and functional group arrays often found in natural products make these secondary metabolites a rich source of new compounds that can disrupt critical protein-protein binding events.
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Affiliation(s)
- Susanna T. S. Chan
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Paresma R. Patel
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Tanya R. Ransom
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Curtis J. Henrich
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702-1201, United States
| | - Tawnya C. McKee
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Andrew K. L. Goey
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Kristina M. Cook
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - William D. Figg
- Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - James B. McMahon
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Martin J. Schnermann
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
| | - Kirk R. Gustafson
- Molecular Targets Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland 21702-1201, United States
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9
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Lao BB, Drew K, Guarracino DA, Brewer TF, Heindel DW, Bonneau R, Arora PS. Rational design of topographical helix mimics as potent inhibitors of protein-protein interactions. J Am Chem Soc 2014; 136:7877-88. [PMID: 24972345 PMCID: PMC4353027 DOI: 10.1021/ja502310r] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
![]()
Protein–protein
interactions encompass large surface areas, but
often a handful of key residues dominate the binding energy landscape.
Rationally designed small molecule scaffolds that reproduce the relative
positioning and disposition of important binding residues, termed
“hotspot residues”, have been shown to successfully
inhibit specific protein complexes. Although this strategy has led
to development of novel synthetic inhibitors of protein complexes,
often direct mimicry of natural amino acid residues does not lead
to potent inhibitors. Experimental screening of focused compound libraries
is used to further optimize inhibitors but the number of possible
designs that can be efficiently synthesized and experimentally tested
in academic settings is limited. We have applied the principles of
computational protein design to optimization of nonpeptidic helix
mimics as ligands for protein complexes. We describe the development
of computational tools to design helix mimetics from canonical and
noncanonical residue libraries and their application to two therapeutically
important protein–protein interactions: p53-MDM2 and p300-HIF1α.
The overall study provides a streamlined approach for discovering
potent peptidomimetic inhibitors of protein–protein interactions.
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Affiliation(s)
- Brooke Bullock Lao
- Department of Chemistry and ‡Departments of Biology and Computer Science, New York University , New York, New York 10003, United States
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10
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In vivo modulation of hypoxia-inducible signaling by topographical helix mimetics. Proc Natl Acad Sci U S A 2014; 111:7531-6. [PMID: 24821806 DOI: 10.1073/pnas.1402393111] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Development of small-molecule inhibitors of protein-protein interactions is a fundamental challenge at the interface of chemistry and cancer biology. Successful methods for design of protein-protein interaction inhibitors include computational and experimental high-throughput and fragment-based screening strategies to locate small-molecule fragments that bind protein surfaces. An alternative rational design approach seeks to mimic the orientation and disposition of critical binding residues at protein interfaces. We describe the design, synthesis, biochemical, and in vivo evaluation of a small-molecule scaffold that captures the topography of α-helices. We designed mimics of a key α-helical domain at the interface of hypoxia-inducible factor 1α and p300 to develop inhibitors of hypoxia-inducible signaling. The hypoxia-inducible factor/p300 interaction regulates the transcription of key genes, whose expression contributes to angiogenesis, metastasis, and altered energy metabolism in cancer. The designed compounds target the desired protein with high affinity and in a predetermined manner, with the optimal ligand providing effective reduction of tumor burden in experimental animal models.
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11
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Protein domain mimetics as in vivo modulators of hypoxia-inducible factor signaling. Proc Natl Acad Sci U S A 2013; 110:15602-7. [PMID: 24019500 DOI: 10.1073/pnas.1312473110] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Selective blockade of gene expression by designed small molecules is a fundamental challenge at the interface of chemistry, biology, and medicine. Transcription factors have been among the most elusive targets in genetics and drug discovery, but the fields of chemical biology and genetics have evolved to a point where this task can be addressed. Herein we report the design, synthesis, and in vivo efficacy evaluation of a protein domain mimetic targeting the interaction of the p300/CBP coactivator with the transcription factor hypoxia-inducible factor-1α. Our results indicate that disrupting this interaction results in a rapid down-regulation of hypoxia-inducible genes critical for cancer progression. The observed effects were compound-specific and dose-dependent. Gene expression profiling with oligonucleotide microarrays revealed effective inhibition of hypoxia-inducible genes with relatively minimal perturbation of nontargeted signaling pathways. We observed remarkable efficacy of the compound HBS 1 in suppressing tumor growth in the fully established murine xenograft models of renal cell carcinoma of the clear cell type. Our results suggest that rationally designed synthetic mimics of protein subdomains that target the transcription factor-coactivator interfaces represent a unique approach for in vivo modulation of oncogenic signaling and arresting tumor growth.
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Abstract
Osteoarthritis (OA) is characterized by the breakdown of articular cartilage that is mediated in part by increased production of matrix metalloproteinases (MMPs) and aggrecanases (ADAMTS), enzymes that degrade components of the cartilage extracellular matrix. Efforts to design synthetic inhibitors of MMPs/ADAMTS have only led to limited clinical success. In addition to pharmacologic therapies, physiologic joint loading is widely recommended as a nonpharmacologic approach to improve joint function in osteoarthritis. Clinical trials report that moderate levels of exercise exert beneficial effects, such as improvements in pain and physical function. Experimental studies demonstrate that mechanical loading mitigates joint destruction through the downregulation of MMPs/ADAMTS. However, the molecular mechanisms underlying these effects of physiologic loading on arthritic joints are not well understood. We review here the recent progress on mechanotransduction in articular joints, highlighting the mediators and pathways in the maintenance of cartilage integrity, especially in the prevention of cartilage degradation in OA.
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Affiliation(s)
- Daniel J. Leong
- Department of Orthopaedic Surgery, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
- Department of Radation Oncology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
- Oncophysics Research Institute, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
| | - John A. Hardin
- Department of Orthopaedic Surgery, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
| | - Neil J. Cobelli
- Department of Orthopaedic Surgery, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
| | - Hui B. Sun
- Department of Orthopaedic Surgery, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
- Department of Radation Oncology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
- Oncophysics Research Institute, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York
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13
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Abstract
The exquisite specificity of proteins is a key feature driving their application to anticancer therapies. The therapeutic potential of another fundamental property of proteins, their ability to be regulated by molecular cues in their environment, is unknown. Here, we describe a synthetic biology strategy for designing protein therapeutics that autonomously activate a therapeutic function in response to a specific cancer marker of choice. We demonstrate this approach by creating a prodrug-activating enzyme that selectively kills human cancer cells that accumulate the marker hypoxia-inducible factor 1α. This property arises primarily through increased cellular accumulation of the enzyme in the presence of the marker. Our strategy offers a platform for the development of inherently selective protein therapeutics for cancer and other diseases.
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Okumura F, Li Y, Itoh N, Nakanishi T, Isobe M, Andrews GK, Kimura T. The zinc-sensing transcription factor MTF-1 mediates zinc-induced epigenetic changes in chromatin of the mouse metallothionein-I promoter. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1809:56-62. [PMID: 21035574 DOI: 10.1016/j.bbagrm.2010.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 10/10/2010] [Accepted: 10/18/2010] [Indexed: 10/18/2022]
Abstract
Metallothionein (MT) is a small, cysteine-rich protein active in zinc homeostasis, cadmium detoxification, and protection against reactive oxygen species. Mouse MT-I gene transcription is regulated by metal response element-binding transcription factor-1 (MTF-1), which is recruited to the promoter by zinc. We examined alterations in the chromatin structure of the MT-I promoter associated with enhanced transcriptional activation. MTF-1 proved essential for zinc-induced epigenetic changes in the MT-I promoter. Chromatin immunoprecipitation assays demonstrated that zinc treatment rapidly decreased Lys⁴-trimethylated and Lys⁹-acetylated histone H3 in the promoter and decreased total histone H3 but not histone H3.3. Micrococcal nuclease sensitivity of the MT-I promoter was increased by zinc. Thus, the chromatin structure in the promoter may be locally disrupted by zinc-induced nucleosome removal. Without MTF-1 these changes were not observed, and an MTF-1 deletion mutant recruited to the MT-I promoter by zinc that did not recruit the coactivator p300 or activate MT-I transcription did not affect histone H3 in the MT-I promoter in response to zinc. Interleukin-6, which induces MT-I transcription independently of MTF-1, did not reduce histone H3 levels in the promoter. Rapid disruption of nucleosome structure at the MT-I promoter is mediated by zinc-responsive recruitment of an active MTF-1-coactivator complex.
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Affiliation(s)
- Fumika Okumura
- Department of Toxicology, Faculty of Pharmaceutical Sciences, Setsunan University, Osaka 573-0101, Japan
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16
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Bom APDA, Freitas MS, Moreira FS, Ferraz D, Sanches D, Gomes AMO, Valente AP, Cordeiro Y, Silva JL. The p53 core domain is a molten globule at low pH: functional implications of a partially unfolded structure. J Biol Chem 2009; 285:2857-66. [PMID: 19933157 PMCID: PMC2807339 DOI: 10.1074/jbc.m109.075861] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
p53 is a transcription factor that maintains genome integrity, and its function is lost in 50% of human cancers. The majority of p53 mutations are clustered within the core domain. Here, we investigate the effects of low pH on the structure of the wild-type (wt) p53 core domain (p53C) and the R248Q mutant. At low pH, the tryptophan residue is partially exposed to the solvent, suggesting a fluctuating tertiary structure. On the other hand, the secondary structure increases, as determined by circular dichroism. Binding of the probe bis-ANS (bis-8-anilinonaphthalene-1-sulfonate) indicates that there is an increase in the exposure of hydrophobic pockets for both wt and mutant p53C at low pH. This behavior is accompanied by a lack of cooperativity under urea denaturation and decreased stability under pressure when p53C is in acidic pH. Together, these results indicate that p53C acquires a partially unfolded conformation (molten-globule state) at low pH (5.0). The hydrodynamic properties of this conformation are intermediate between the native and denatured conformation. 1H-15N HSQC NMR spectroscopy confirms that the protein has a typical molten-globule structure at acidic pH when compared with pH 7.2. Human breast cells in culture (MCF-7) transfected with p53-GFP revealed localization of p53 in acidic vesicles, suggesting that the low pH conformation is present in the cell. Low pH stress also tends to favor high levels of p53 in the cells. Taken together, all of these data suggest that p53 may play physiological or pathological roles in acidic microenvironments.
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Affiliation(s)
- Ana Paula D Ano Bom
- Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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17
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Targeting protein–protein interactions for therapeutic intervention: a challenge for the future. Future Med Chem 2009; 1:65-93. [DOI: 10.4155/fmc.09.12] [Citation(s) in RCA: 187] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background: Over the last two decades, an increasing research effort in academia and industry has focused on the modulation (both inhibition and stabilization) of protein–protein interactions (PPIs) in order to develop novel therapeutic approaches and target-selective agents in drug discovery. Discussion: The diversity and complexity of highly dynamic systems such as PPIs present many challenges for the identification of drug-like molecules with the ability to modulate the PPI with the necessary selectivity and potency. In this review, a number of these strategies will be presented along with a critical overview of the challenges and potential solutions relating to the exploitation of PPIs as molecular targets. Conclusions: Both traditional drug discovery approaches and some more recently developed innovative strategies have already provided valuable tools for the discovery of PPI modulators, and a number of successful examples have highlighted the potential of targeting PPIs for therapeutic intervention, especially in the oncology area.
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18
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Cho H, Ahn DR, Park H, Yang EG. Modulation of p300 binding by posttranslational modifications of the C-terminal activation domain of hypoxia-inducible factor-1alpha. FEBS Lett 2007; 581:1542-8. [PMID: 17382325 DOI: 10.1016/j.febslet.2007.03.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2007] [Revised: 02/19/2007] [Accepted: 03/08/2007] [Indexed: 12/25/2022]
Abstract
Posttranslational modifications of hypoxia-inducible factor-1alpha (HIF-1alpha) influence HIF-mediated transcription, likely by affecting binding to p300/cAMP-response element-binding protein (CBP). To systematically analyze the HIF-1alpha-p300/CBP interaction, we developed a fluorescence polarization-based binding assay, employing fluorescein-labeled peptides derived from the C-terminal transactivation domain (C-TAD) of HIF-1alpha. After optimized for effectively capturing p300/CBP, the assay was utilized for evaluating direct effects of posttranslational modifications of the HIF-1alpha C-TAD on p300 binding. The results demonstrated that asparagine hydroxylation and S-nitrosylation of HIF-1alpha decrease p300 binding, while its phosphorylation does not affect p300 binding, which was reconfirmed by competitive inhibition analyses using mutant peptides.
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Affiliation(s)
- Hyunju Cho
- Life Sciences Division, Korea Institute of Science and Technology, Seoul, Republic of Korea
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19
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Pavan Kumar GV, Ashok Reddy BA, Arif M, Kundu TK, Narayana C. Surface-Enhanced Raman Scattering Studies of Human Transcriptional Coactivator p300. J Phys Chem B 2006; 110:16787-92. [PMID: 16913819 DOI: 10.1021/jp063071e] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report for the first time the surface-enhanced Raman scattering (SERS) studies on p300, a large multidomain transcriptional coactivator protein. Vibration spectral analysis has been performed in an attempt to understand the structure of the p300 in the absence of its crystal structure. Strong Raman bands associated with amides I-III have been observed in the protein spectra. This has been confirmed by performing SERS on deuterated p300. We also observe Raman bands associated with the alpha-helix, tryptophan, phenylalanine, tyrosine, and histidine. These bands will provide an ideal tool to study the drug-protein interactions in therapeutics using SERS. We have successfully demonstrated the chloride ion effect on the SERS of p300. The Raman intensity increases in the SERS spectra upon addition of chloride ion along with appearance of new modes. We have developed a new method, namely, the "sandwich technique", which could be used to perform SERS experiments on proteins in dry conditions.
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Affiliation(s)
- G V Pavan Kumar
- Light Scattering Laboratory, Chemistry and Physics of Materials Unit, and Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India
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20
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Gaber T, Dziurla R, Tripmacher R, Burmester GR, Buttgereit F. Hypoxia inducible factor (HIF) in rheumatology: low O2! See what HIF can do! Ann Rheum Dis 2005; 64:971-80. [PMID: 15800008 PMCID: PMC1755583 DOI: 10.1136/ard.2004.031641] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Maintenance of oxygen homoeostasis is the basic principle in cell proliferation, differentiation, survival, and function in all higher organisms. The transcription factor, HIF (hypoxia inducible factor) has a central role in oxygen homoeostasis, and is indispensably linked to energy metabolism. Abnormally reduced oxygen concentrations leading to dysfunctional cell metabolism are found in rheumatoid arthritis and hence, knowledge of the molecular adaptive responses to hypoxia and the involvement of HIF in the pathogenesis of RA are interesting.
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Affiliation(s)
- T Gaber
- Department of Rheumatology and Clinical Immunology, Charité University Hospital, Schumannstrasse 20/21, 10117 Berlin, Germany
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21
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Thomas MC, Chiang CM. E6 oncoprotein represses p53-dependent gene activation via inhibition of protein acetylation independently of inducing p53 degradation. Mol Cell 2005; 17:251-64. [PMID: 15664194 DOI: 10.1016/j.molcel.2004.12.016] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2004] [Revised: 07/08/2004] [Accepted: 12/15/2004] [Indexed: 02/04/2023]
Abstract
The mechanism employed by DNA tumor viruses to inhibit p53-dependent transcription from chromatin is poorly understood. Here, we use in vitro-reconstituted chromatin and UV-irradiated cells to define the mechanism of human papillomavirus E6 oncoprotein in repressing p53-dependent transcription. We demonstrate that E6 does not prevent p53 or p300 recruitment to the chromatin but inhibits p300-mediated acetylation on p53 and nucleosomal core histones. This suppression of protein acetylation requires the E6-interacting regions of p300. Moreover, E6 mutants unable to interact with p53 or p300, but not deficient in inducing p53 degradation, fail to inhibit p53-mediated activation, indicating that a p53-E6-p300-containing protein complex is critical for repressing p53-targeted gene activation. That E6 acts as a molecular switch converting p53-p300 from an activating complex to a repressing entity on the chromatin, which occurs independently of E6AP-mediated protein degradation pathway, may represent a general mechanism for gene regulation.
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Affiliation(s)
- Mary C Thomas
- Department of Biochemistry, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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22
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De Guzman RN, Wojciak JM, Martinez-Yamout MA, Dyson HJ, Wright PE. CBP/p300 TAZ1 domain forms a structured scaffold for ligand binding. Biochemistry 2005; 44:490-7. [PMID: 15641773 DOI: 10.1021/bi048161t] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The transcriptional coactivator protein CBP and its paralog p300 each contain two homologous zinc-containing TAZ domains, which constitute the interaction sites for a number of transcription factors. Previous reports of the three-dimensional structures of TAZ1 in complex with binding partners and of the isolated CBP TAZ2 domain show a distinctive topology composed of four amphipathic helices, organized by three zinc-binding clusters with HCCC-type coordination. The isolated CBP TAZ2 domain forms a stable three-dimensional structure in solution, but a recent report [Dial, R., Sun, Z., and Freedman, S. J. (2003) Biochemistry 42, 9937] suggested that the isolated p300 TAZ1 domain lacks a well-defined structure and behaves like a molten globule, even in the presence of Zn(2+), and that the formation of a stable three-dimensional structure requires binding of a protein partner. In marked contrast to this result, we find that both the CBP and p300 TAZ domains in the presence of stoichiometric concentrations of Zn(2+) adopt a well-defined structure in solution in the absence of binding partners. We have determined the three-dimensional structure of the isolated CBP TAZ1 domain by NMR methods and show that it has the same structure in the presence and absence of binding partners. This is an important finding: whether the free TAZ1 domain forms a folded structure or behaves as a molten globule will have a significant bearing on the mechanism of protein-protein recognition. Although TAZ1 and TAZ2 share many structural similarities, there is a major structural difference: the fourth helix is oriented in opposite directions in the TAZ1 and TAZ2 domains. The structure of the free TAZ1 domain suggests that this difference is an inherent feature that determines binding specificity and facilitates discrimination between different subsets of transcription factors by the two TAZ domains.
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Affiliation(s)
- Roberto N De Guzman
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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23
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Brahimi-Horn MC, Pouysségur J. The hypoxia-inducible factor and tumor progression along the angiogenic pathway. ACTA ACUST UNITED AC 2005; 242:157-213. [PMID: 15598469 DOI: 10.1016/s0074-7696(04)42004-x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The hypoxia-inducible factor (HIF) is a transcription factor that plays a key role in the response of cells to oxygen levels. HIF is a heterodimer of alpha- and beta-subunits where the alpha-subunit is translated constitutively but has a very short half-life under normal oxygen concentrations. Negative regulation of the half-life and activity of the alpha-subunit is dependent on its posttranslational hydroxylation by hydroxylases that are dependent on oxygen for activity. Thus under low oxygen (hypoxic) conditions the hydroxylases are inactive and the alpha-subunit is stable and able to interact with the beta-subunit to bind and induce transcription of target genes. Hypoxic conditions are encountered in development and in disease states such as cancer. Tumors that have outstripped their blood supply become hypoxic and express high levels of HIF. HIF in turn targets genes that induce survival, glycolysis, and angiogenesis, a form of neovascularization, which ensures the tumor with a continued supply of oxygen and nutrients for further growth.
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Affiliation(s)
- M Christiane Brahimi-Horn
- Institute of Signaling, Developmental Biology and Cancer Research, CNRS UMR 6543, Centre A. Lacassagne, 06189 Nice, France
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24
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Halonen P, Tammenkoski M, Niiranen L, Huopalahti S, Parfenyev AN, Goldman A, Baykov A, Lahti R. Effects of Active Site Mutations on the Metal Binding Affinity, Catalytic Competence, and Stability of the Family II Pyrophosphatase from Bacillus subtilis. Biochemistry 2005; 44:4004-10. [PMID: 15751976 DOI: 10.1021/bi047926u] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Family II inorganic pyrophosphatases (PPases) have been recently found in a variety of bacteria. Their primary and tertiary structures differ from those of the well-known family I PPases, although both have a binuclear metal center directly involved in catalysis. Here, we examined the effects of mutating one Glu, four His, and five Asp residues forming or close to the metal center on Mn(2+) binding affinity, catalysis, oligomeric structure, and thermostability of the family II PPase from Bacillus subtilis (bsPPase). Mutations H9Q, D13E, D15E, and D75E in two metal-binding subsites caused profound (10(4)- to 10(6)-fold) reductions in the binding affinity for Mn(2+). Most of the mutations decreased k(cat) for MgPP(i) by 2-3 orders of magnitude when measured with Mn(2+) or Mg(2+) bound to the high-affinity subsite and Mg(2+) bound to both the low-affinity subsite and pyrophosphate. In the E78D variant, the k(cat) for the Mn-bound enzyme was decreased 120-fold, converting bsPPase from an Mn-specific to an Mg-specific enzyme. K(m) values were less affected by the mutations, and, interestingly, were decreased in most cases. Mutations of His(97) and His(98) residues, which lie near the subunit interface, greatly destabilized the bsPPase dimer, whereas most other mutations stabilized it. Mn(2+), in sharp contrast to Mg(2+), conferred high thermostability to wild-type bsPPase, although this effect was reduced by all of the mutations except D203E. These results indicate that family II PPases have a more integrated active site structure than family I PPases and are consequently more sensitive to conservative mutations.
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Affiliation(s)
- Pasi Halonen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
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25
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Fladvad M, Zhou K, Moshref A, Pursglove S, Säfsten P, Sunnerhagen M. N and C-terminal Sub-regions in the c-Myc Transactivation Region and their Joint Role in Creating Versatility in Folding and Binding. J Mol Biol 2005; 346:175-89. [PMID: 15663936 DOI: 10.1016/j.jmb.2004.11.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/12/2004] [Accepted: 11/12/2004] [Indexed: 11/15/2022]
Abstract
The proto-oncogene c-myc governs the expression of a number of genes targeting cell growth and apoptosis, and its expression levels are distorted in many cancer forms. The current investigation presents an analysis by proteolysis, circular dichroism, fluorescence and Biacore of the folding and ligand-binding properties of the N-terminal transactivation domain (TAD) in the c-Myc protein. A c-Myc sub-region comprising residues 1-167 (Myc1-167) has been investigated that includes the unstructured c-Myc transactivation domain (TAD, residues 1-143) together with a C-terminal segment, which appears to promote increased folding. Myc1-167 is partly helical, binds both to the target proteins Myc modulator-1 (MM-1) and TATA box-binding protein (TBP), and displays the characteristics of a molten globule. Limited proteolysis divides Myc1-167 in two halves, by cleaving in a predicted linker region between two hotspot mutation regions: Myc box I (MBI) and Myc box II (MBII). The N-terminal half (Myc1-88) is unfolded and does not alone bind to target proteins, whereas the C-terminal half (Myc92-167) has a partly helical fold and specifically binds both MM-1 and TBP. Although this might suggest a bipartite organization in the c-Myc TAD, none of the N and C-terminal fragments bind target protein with as high affinity as the entire Myc1-167, or display molten globule properties. Furthermore, merely linking the MBI with the C-terminal region, in Myc38-167, is not sufficient to achieve binding and folding properties as in Myc1-167. Thus, the entire N and C-terminal regions of c-Myc TAD act in concert to achieve high specificity and affinity to two structurally and functionally orthogonal target proteins, TBP and MM-1, possibly through a mechanism involving molten globule formation. This hints towards understanding how binding of a range of targets can be accomplished to a single transactivation domain.
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Affiliation(s)
- Malin Fladvad
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
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26
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Nyborg JK, Peersen OB. That zincing feeling: the effects of EDTA on the behaviour of zinc-binding transcriptional regulators. Biochem J 2004; 381:e3-4. [PMID: 15270700 PMCID: PMC1133908 DOI: 10.1042/bj20041096] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Zinc-binding proteins account for nearly half of the transcription regulatory proteins in the human genome and are the most abundant class of proteins in the human proteome. The zinc-binding transcriptional regulatory proteins utilize Zn2+ to fold structural domains that participate in intermolecular interactions. A study by Matt et al. in this issue of the Biochemical Journal has examined the transcription factor binding properties of the zinc-binding module C/H1 (cysteine/histidine-rich region 1) found in the transcriptional co-activator proteins CBP (CREB-binding protein) and p300. Their studies revealed that EDTA treatment of native C/H1 leads to irreversible denaturation and aggregation. Of particular concern is their finding that unfolded C/H1 participates in non-specific protein-protein interactions. The implications of these results are significant. EDTA is a very potent zinc-chelating agent that is used ubiquitously in protein interaction studies and in molecular biology in general. The potentially detrimental effects of EDTA on the structure and interactions of zinc-binding proteins should be taken into account in the interpretation of a sizeable number of published studies and must be considered in future experiments.
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Affiliation(s)
- Jennifer K Nyborg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA.
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27
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Schmid T, Zhou J, Köhl R, Brüne B. p300 relieves p53-evoked transcriptional repression of hypoxia-inducible factor-1 (HIF-1). Biochem J 2004; 380:289-95. [PMID: 14992692 PMCID: PMC1224165 DOI: 10.1042/bj20031299] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Revised: 02/19/2004] [Accepted: 03/01/2004] [Indexed: 12/31/2022]
Abstract
HIF-1 (hypoxia-inducible factor-1), a heterodimeric transcription factor comprising HIF-1alpha and HIF-1beta subunits, serves as a key regulator of metabolic adaptation to hypoxia. HIF-1 activity largely increases during hypoxia by attenuating pVHL (von Hippel-Lindau protein)-dependent ubiquitination and subsequent 26 S-proteasomal degradation of HIF-1alpha. Besides HIF-1, the transcription factor and tumour suppressor p53 accumulates and is activated under conditions of prolonged/severe hypoxia. Recently, the interaction between p53 and HIF-1alpha was reported to evoke HIF-1alpha degradation. Destruction of HIF-1alpha by p53 was corroborated in the present study by using pVHL-deficient RCC4 (renal carcinoma) cells, supporting the notion of a pVHL-independent degradation process. In addition, low p53 expression repressed HIF-1 transactivation without affecting HIF-1alpha protein amount. Establishing that p53-evoked inhibition of HIF-1 reporter activity was relieved upon co-transfection of p300 suggested competition between p53 and HIF-1 for limiting amounts of the shared co-activator p300. This assumption was confirmed by showing competitive binding of in vitro transcription/translation-generated p53 and HIF-1alpha to the CH1 domain of p300 in vitro. We conclude that low p53 expression attenuates HIF-1 transactivation by competing for p300, whereas high p53 expression destroys the HIF-1alpha protein and thereby eliminates HIF-1 reporter activity. Thus once p53 becomes activated under conditions of severe hypoxia/anoxia, it contributes to terminating HIF-1 responses.
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Affiliation(s)
- Tobias Schmid
- Department of Cell Biology, Faculty of Biology, University of Kaiserslautern, Erwin Schroedinger Strasse 13/4, 67663 Kaiserslautern, Germany
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28
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Mazure NM, Brahimi-Horn MC, Berta MA, Benizri E, Bilton RL, Dayan F, Ginouvès A, Berra E, Pouysségur J. HIF-1: master and commander of the hypoxic world. A pharmacological approach to its regulation by siRNAs. Biochem Pharmacol 2004; 68:971-80. [PMID: 15313390 DOI: 10.1016/j.bcp.2004.04.022] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Accepted: 04/21/2004] [Indexed: 11/23/2022]
Abstract
The hypoxia-inducible factor-1 (HIF-1) is primarily involved in the sensing and adapting of cells to changes in the O2 level, which is essential for their viability. It is important that this critical transcription factor be tightly regulated in order for cells to respond to a wide range of O2 concentrations. HIF-1 regulation by post-translational modification is the central theme of the scenario of O2 homeostasis. The alpha subunit of HIF-1 is the principal actor while the supporting actors (PHDs, FIH-1, ARD1, CITED2, p300...) all contribute to the complexity of the grand finale. It is well established that HIF-1 expression and activation correlates with tumor progression and resistance to cancer treatments. We will introduce the different actors involved in HIF-1 regulation, and their mechanisms of action via invalidation by siRNAs and discuss therapies targeting HIF-1, to selectively kill tumor cells that adapt to low O2 concentrations.
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Affiliation(s)
- Nathalie M Mazure
- Institute of Signaling, Developmental Biology and Cancer Research, CNRS-UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
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