1
|
Banerjee C, Nag S, Goyal M, Saha D, Siddiqui AA, Mazumder S, Debsharma S, Pramanik S, Bandyopadhyay U. Nuclease activity of Plasmodium falciparum Alba family protein PfAlba3. Cell Rep 2023; 42:112292. [PMID: 36947546 DOI: 10.1016/j.celrep.2023.112292] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 01/06/2023] [Accepted: 03/06/2023] [Indexed: 03/23/2023] Open
Abstract
Plasmodium falciparum Alba domain-containing protein Alba3 (PfAlba3) is ubiquitously expressed in intra-erythrocytic stages of Plasmodium falciparum, but the function of this protein is not yet established. Here, we report an apurinic/apyrimidinic site-driven intrinsic nuclease activity of PfAlba3 assisted by divalent metal ions. Surface plasmon resonance and atomic force microscopy confirm sequence non-specific DNA binding by PfAlba3. Upon binding, PfAlba3 cleaves double-stranded DNA (dsDNA) hydrolytically. Mutational studies coupled with mass spectrometric analysis indicate that K23 is the essential residue in modulating the binding to DNA through acetylation-deacetylation. We further demonstrate that PfSir2a interacts and deacetylates K23-acetylated PfAlba3 in favoring DNA binding. Hence, K23 serves as a putative molecular switch regulating the nuclease activity of PfAlba3. Thus, the nuclease activity of PfAlba3, along with its apurinic/apyrimidinic (AP) endonuclease feature identified in this study, indicates a role of PfAlba3 in DNA-damage response that may have a far-reaching consequence in Plasmodium pathogenicity.
Collapse
Affiliation(s)
- Chinmoy Banerjee
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Shiladitya Nag
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Manish Goyal
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Debanjan Saha
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Asim Azhar Siddiqui
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Somnath Mazumder
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Subhashis Debsharma
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Saikat Pramanik
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India
| | - Uday Bandyopadhyay
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata, West Bengal 700032, India; Division of Molecular Medicine, Bose Institute, EN 80, Sector V, Bidhan Nagar Kolkata, 700091, West Bengal, India.
| |
Collapse
|
2
|
Hu G, Zhou HX. Magnesium ions mediate ligand binding and conformational transition of the SAM/SAH riboswitch. bioRxiv 2023:2023.03.12.532287. [PMID: 36945415 PMCID: PMC10029009 DOI: 10.1101/2023.03.12.532287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
The SAM/SAH riboswitch binds S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) with similar affinities. Mg 2+ is generally known to stabilize RNA structures by neutralizing phosphates, but how it contributes to ligand binding and conformational transition is understudied. Here, extensive molecular dynamics simulations (totaling 120 μs) identified over 10 inner-shell Mg 2+ ions in the SAM/SAH riboswitch. Six of them line the two sides of a groove to widen it and thereby pre-organize the riboswitch for ligand entry. They also form outer-shell coordination with the ligands and stabilize an RNA-ligand hydrogen bond, which effectively diminish the selectivity between SAM and SAH. One Mg 2+ ion unique to the apo form maintains the Shine-Dalgarno sequence in an autonomous mode and thereby facilitates its release for ribosome binding. Mg 2+ thus plays vital roles in SAM/SAH riboswitch function.
Collapse
Affiliation(s)
- Guodong Hu
- Shandong Key Laboratory of Biophysics, Dezhou University, Dezhou 253023, China
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607
| | - Huan-Xiang Zhou
- Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607
- Department of Physics, University of Illinois Chicago, Chicago, IL 60607
| |
Collapse
|
3
|
Fan L, Russell DH. An ion mobility-mass spectrometry study of copper-metallothionein-2A: binding sites and stabilities of Cu-MT and mixed metal Cu-Ag and Cu-Cd complexes. Analyst 2023; 148:546-555. [PMID: 36545796 PMCID: PMC9904198 DOI: 10.1039/d2an01556k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The presence of Cu, a highly redox active metal, is known to damage DNA as well as other cellular components, but the adverse effects of cellular Cu can be mitigated by metallothioneins (MT), small cysteine rich proteins that are known to bind to a broad range of metal ions. While metal ion binding has been shown to involve the cysteine thiol groups, the specific ion binding sites are controversial as are the overall structure and stability of the Cu-MT complexes. Here, we report results obtained using nano-electrospray ionization mass spectrometry and ion mobility-mass spectrometry for several Cu-MT complexes and compare our results with those previously reported for Ag-MT complexes. The data include determination of the stoichiometries of the complex (Cui-MT, i = 1-19), and Cu+ ion binding sites for complexes where i = 4, 6, and 10 using bottom-up and top-down proteomics. The results show that Cu+ ions first bind to the β-domain to form Cu4MT then Cu6MT, followed by addition of four Cu+ ions to the α-domain to form a Cu10-MT complex. Stabilities of the Cui-MT (i = 4, 6 and 10) obtained using collision-induced unfolding (CIU) are reported and compared with previously reported CIU data for Ag-MT complexes. We also compare CIU data for mixed metal complexes (CuiAgj-MT, where i + j = 4 and 6 and CuiCdj, where i + j = 4 and 7). Lastly, higher order Cui-MT complexes, where i = 11-19, were also detected at higher concentrations of Cu+ ions, and the metalated product distributions observed are compared to previously reported results for Cu-MT-1A (Scheller et al., Metallomics, 2017, 9, 447-462).
Collapse
Affiliation(s)
- Liqi Fan
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA.
| | - David H Russell
- Department of Chemistry, Texas A&M University, College Station, TX 77843, USA.
| |
Collapse
|
4
|
Hao J, Cao D, Zhao Q, Zhang D, Wang H. Intramolecular Folding of PolyT Oligonucleotides Induced by Cooperative Binding of Silver(I) Ions. Molecules 2022; 27:molecules27227842. [PMID: 36431941 PMCID: PMC9694225 DOI: 10.3390/molecules27227842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/05/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022]
Abstract
Ag+-bridged T-Ag+-T was recently discovered in a Ag+-DNA nanowire crystal, but it was reported that Ag+ had little to no affinity to T nucleobases and T-rich oligonucleotides in solution. Therefore, the binding mode for the formation of this type of novel metallo base pair in solution is elusive. Herein, we demonstrate that Ag+ can interact with polyT oligonucleotides once the concentration of Ag+ in solution exceeds a threshold value. The threshold value is independent of the concentration of the polyT oligonucleotide but is inversely proportional to the length of the polyT oligonucleotide. The polyT oligonucleotides are intramolecularly folded due to their positively cooperative formation and the stack of T-Ag+-T base pairs, resulting in the 5'- and 3'-ends being in close proximity to each other. The intramolecular Ag+-folded polyT oligonucleotide has a higher thermal stability than the duplex and can be reversibly modulated by cysteine.
Collapse
Affiliation(s)
- Jinghua Hao
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong Cao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Qiang Zhao
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dapeng Zhang
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: ; Tel.: +86-10-62849611; Fax: +86-10-62849600
| | - Hailin Wang
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
5
|
Engström MT, Virtanen V, Salminen JP. Influence of the Hydrolyzable Tannin Structure on the Characteristics of Insoluble Hydrolyzable Tannin-Protein Complexes. J Agric Food Chem 2022; 70:13036-13048. [PMID: 35708502 PMCID: PMC9585579 DOI: 10.1021/acs.jafc.2c01765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Precipitation of bovine serum albumin (BSA) by 21 hydrolyzable tannins (HTs) and the characteristics of the insoluble complexes were studied stoichiometrically by ultra-performance liquid chromatography. With regard to HT monomers, the protein precipitation and the characteristic of the formed precipitates were unique for each studied HT and depended upon the functional groups present in the structures. The monomeric units comprising the oligomers formed the functional units important for the protein precipitation capacity, and small structural differences among the monomer units were less important than the overall oligomer size and flexibility. In addition, the greater tendency of certain HTs to form insoluble complexes when mixed with BSA was partially linked to the higher self-association and consequent stronger cooperative binding of these HTs with BSA.
Collapse
|
6
|
Farr CV, El-Kasaby A, Erdem FA, Sucic S, Freissmuth M, Sandtner W. Cooperative Binding of Substrate and Ions Drives Forward Cycling of the Human Creatine Transporter-1. Front Physiol 2022; 13:919439. [PMID: 35837012 PMCID: PMC9273935 DOI: 10.3389/fphys.2022.919439] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/09/2022] [Indexed: 11/25/2022] Open
Abstract
Creatine serves as an ATP buffer and is thus an integral component of cellular energy metabolism. Most cells maintain their creatine levels via uptake by the creatine transporter (CRT-1, SLC6A8). The activity of CRT-1, therefore, is a major determinant of cytosolic creatine concentrations. We determined the kinetics of CRT-1 in real time by relying on electrophysiological recordings of transport-associated currents. Our analysis revealed that CRT-1 harvested the concentration gradient of NaCl and the membrane potential but not the potassium gradient to achieve a very high concentrative power. We investigated the mechanistic basis for the ability of CRT-1 to maintain the forward cycling mode in spite of high intracellular concentrations of creatine: this is achieved by cooperative binding of substrate and co-substrate ions, which, under physiological ion conditions, results in a very pronounced (i.e. about 500-fold) drop in the affinity of creatine to the inward-facing state of CRT-1. Kinetic estimates were integrated into a mathematical model of the transport cycle of CRT-1, which faithfully reproduced all experimental data. We interrogated the kinetic model to examine the most plausible mechanistic basis of cooperativity: based on this systematic exploration, we conclude that destabilization of binary rather than ternary complexes is necessary for CRT-1 to maintain the observed cytosolic creatine concentrations. Our model also provides a plausible explanation why neurons, heart and skeletal muscle cells must express a creatine releasing transporter to achieve rapid equilibration of the intracellular creatine pool.
Collapse
Affiliation(s)
| | | | | | | | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | | |
Collapse
|
7
|
Abstract
INTRODUCTION : Vaccines based on multiple antigens often induce an immune response which is higher than that triggered by each single component, with antibodies acting cooperatively and synergistically in tackling the infection. AREAS COVERED An interesting example is the antibody response induced by the 4CMenB vaccine, currently licensed for the prevention of Neisseria meningitidis serogroup B (MenB). It contains four antigenic components: Factor H binding protein (fHbp), Neisseria adhesin A (NadA), Neisserial Heparin Binding Antigen (NHBA) and Outer Membrane Vesicles (OMV). Monoclonal and polyclonal antibodies raised by vaccination with 4CMenB show synergistic activity in complement-dependent bacterial killing. This review summarizes published and unpublished data and provides evidence of the added value of multicomponent vaccines. EXPERT OPINION : The ability of 4CMenB vaccine to elicit antibodies targeting multiple surface-exposed antigens is corroborated by the recent data on real world evidences. Bactericidal activity is generally mediated by antibodies that bind to antigens highly expressed on the bacterial surface and immunologically related. However, simultaneous binding of antibodies to various surface-exposed antigens can overcome the threshold density of antigen-antibody complexes needed for complement activation. The data discussed in this review highlight the interplay between antibodies targeting major and minor antigens and their effect on functionality. Clinical trial registration: www.clinicaltrials.gov identifiers of studies with original data mentioned in the article: NCT00937521, NCT00433914, NCT02140762 and NCT02285777.
Collapse
Affiliation(s)
| | | | - Mariagrazia Pizza
- Bacterial Vaccines, GSK, Siena, Italy.,GVGH, GSK Vaccine Institute for Global Health, Siena, Italy
| |
Collapse
|
8
|
Luo T, Xu J, Cheng W, Zhou L, Marsac R, Wu F, Boily JF, Hanna K. Interactions of Anti-Inflammatory and Antibiotic Drugs at Mineral Surfaces Can Control Environmental Fate and Transport. Environ Sci Technol 2022; 56:2378-2385. [PMID: 34910456 DOI: 10.1021/acs.est.1c06449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Various pharmaceutical compounds often coexist in contaminated soils, yet little is known about how their interactions impact their mobility. We here show that two typical antibiotic and anti-inflammatory agents (nalidixic acid (NA) and niflumic acid (NFA)) commonly form dimers at several representative soil- and sediment-building minerals of contrasting composition and structure. Cobinding occurs in the form of a NFA-NA dimer stabilized by hydrogen bonding and van der Waals interactions. Using dynamic column experiments containing goethite-coated sand, we then demonstrated that presorbed NA effectively captured the otherwise weakly binding NFA from solution. Simultaneously injecting NA and NFA to presorbed NA enhanced even further both NA and NFA loadings, thereby altering their transport under flow-through conditions. We also showed that environmental level amounts of natural organic matter can reduce the overall retention in column experiments, yet it does not suppress dimer formation. These environmentally relevant scenarios can be predicted using a new transport model that accounts for kinetics and cobinding reactions of NFA onto NA bound to goethite through metal-bonded, hydrogen-bonded, and outer-sphere complexes. These findings have important implications on assessing the fate of coexisting pharmaceutical compounds under dynamic flow conditions in contaminated soils.
Collapse
Affiliation(s)
- Tao Luo
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, Univ Rennes, ISCR-UMR 6226, F-35000 Rennes, France
| | - Jing Xu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, P. R. China
| | - Wei Cheng
- College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, P. R. China
| | - Lian Zhou
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, Univ Rennes, ISCR-UMR 6226, F-35000 Rennes, France
| | - Rémi Marsac
- CNRS, Univ Rennes, Géosciences Rennes - UMR 6118, F-35000 Rennes, France
| | - Feng Wu
- Hubei Key Lab of Biomass Resource Chemistry and Environmental Biotechnology, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, P. R. China
| | | | - Khalil Hanna
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, Univ Rennes, ISCR-UMR 6226, F-35000 Rennes, France
- Institut Universitaire de France (IUF), MESRI, 1 rue Descartes, 75231 Paris, France
| |
Collapse
|
9
|
Kacsir I, Sipos A, Bényei A, Janka E, Buglyó P, Somsák L, Bai P, Bokor É. Reactive Oxygen Species Production Is Responsible for Antineoplastic Activity of Osmium, Ruthenium, Iridium and Rhodium Half-Sandwich Type Complexes with Bidentate Glycosyl Heterocyclic Ligands in Various Cancer Cell Models. Int J Mol Sci 2022; 23:813. [PMID: 35054999 DOI: 10.3390/ijms23020813] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 02/04/2023] Open
Abstract
Platinum complexes are used in chemotherapy, primarily as antineoplastic agents. In this study, we assessed the cytotoxic and cytostatic properties of a set of osmium(II), ruthenium(II), iridium(III) and rhodium(III) half-sandwich-type complexes with bidentate monosaccharide ligands. We identified 5 compounds with moderate to negligible acute cytotoxicity but with potent long-term cytostatic activity. These structure-activity relationship studies revealed that: (1) osmium(II) p-cymene complexes were active in all models, while rhodium(III) and iridium(III) Cp* complexes proved largely inactive; (2) the biological effect was influenced by the nature of the central azole ring of the ligands—1,2,3-triazole was the most effective, followed by 1,3,4-oxadiazole, while the isomeric 1,2,4-oxadiazole abolished the cytostatic activity; (3) we found a correlation between the hydrophobic character of the complexes and their cytostatic activity: compounds with O-benzoyl protective groups on the carbohydrate moiety were active, compared to O-deprotected ones. The best compound, an osmium(II) complex, had an IC50 value of 0.70 µM. Furthermore, the steepness of the inhibitory curve of the active complexes suggested cooperative binding; cooperative molecules were better inhibitors than non-cooperative ones. The cytostatic activity of the active complexes was abolished by a lipid-soluble antioxidant, vitamin E, suggesting that oxidative stress plays a major role in the biological activity of the complexes. The complexes were active on ovarian cancer, pancreatic adenocarcinoma, osteosarcoma and Hodgkin’s lymphoma cells, but were inactive on primary, non-transformed human fibroblasts, indicating their applicability as potential anticancer agents.
Collapse
|
10
|
Pottoo FH, Salahuddin M, Khan FA, AL Dhamen MA, Alsaeed WJ, Gomaa MS, Vatte C, Alomary MN. Combinatorial Regimen of Carbamazepine and Imipramine Exhibits Synergism against Grandmal Epilepsy in Rats: Inhibition of Pro-Inflammatory Cytokines and PI3K/Akt/mTOR Signaling Pathway. Pharmaceuticals (Basel) 2021; 14:1204. [PMID: 34832986 PMCID: PMC8624327 DOI: 10.3390/ph14111204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/14/2021] [Accepted: 11/16/2021] [Indexed: 02/06/2023] Open
Abstract
Epilepsy is a neurodegenerative disorder that causes recurring seizures. Thirty-five percent of patients remain refractory, with a higher prevalence of depression. We investigated the anticonvulsant efficacy of carbamazepine (CBZ; 20 and 50 mg/kg), imipramine (IMI; 10 and 20 mg/kg) alone, and as a low dose combination. This preclinical investigation included dosing of rats for 14 days followed by elicitation of electroshock on the last day of treatment. Along with behavioral monitoring, the rat hippocampus was processed for quantification of mTOR, IL-1β, IL-6 and TNF-α levels. The histopathological analysis of rat hippocampus was performed to ascertain neuroprotection. In vitro studies and in silico studies were also conducted. We found that the low dose combinatorial therapy of CBZ (20 mg/kg) + IMI (10 mg/kg) exhibits synergism (p < 0.001) in abrogation of maximal electroshock (MES) induced convulsions/tonic hind limb extension (THLE), by reducing levels of pro-inflammatory cytokines, and weakening of the PI3K/Akt/mTOR signal. The combination also exhibits cooperative binding at the Akt. As far as neuroprotection is concerned, the said combination increased cell viability by 166.37% compared to Pentylenetetrazol (PTZ) treated HEK-293 cells. Thus, the combination of CBZ (20 mg/kg) + IMI (10 mg/kg) is a fruitful combination therapy to elevate seizure threshold and provide neuroprotection.
Collapse
Affiliation(s)
- Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (M.A.A.D.); (W.J.A.)
| | - Mohammed Salahuddin
- Department of Clinical Pharmacy Research, Institute for Research and Medical Consultation, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Firdos Alam Khan
- Department of Stem cell Research, Institute for Research and Medical Consultation, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Marwa Abdullah AL Dhamen
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (M.A.A.D.); (W.J.A.)
| | - Walaa Jafar Alsaeed
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (M.A.A.D.); (W.J.A.)
| | - Mohamed S. Gomaa
- Department of Pharmaceutical Chemistry, College of Clinical Pharmacy, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Chittibabu Vatte
- Department of Biochemistry, College of Medicine, Imam Abdul Rahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Mohammad N. Alomary
- National Centre for Biotechnology, Kind Abdulaziz City for Science and Technology (KACST), P.O. Box 1982, Riyadh 11442, Saudi Arabia
| |
Collapse
|
11
|
Pottoo FH, Salahuddin M, Khan FA, Alomar F, AL Dhamen MA, Alhashim AF, Alqattan HH, Gomaa MS, Alomary MN. Thymoquinone Potentiates the Effect of Phenytoin against Electroshock-Induced Convulsions in Rats by Reducing the Hyperactivation of m-TOR Pathway and Neuroinflammation: Evidence from In Vivo, In Vitro and Computational Studies. Pharmaceuticals (Basel) 2021; 14:1132. [PMID: 34832914 PMCID: PMC8618888 DOI: 10.3390/ph14111132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/16/2022] Open
Abstract
Epilepsy is a chronic neurodegenerative disease characterized by multiple seizures, hereto 35% of patients remain poor responders. Phenytoin (PHT; 20 and 40 mg/kg) and thymoquinone (THQ; 40 and 80 mg/kg) were given alone and as a low dose combination for 14 days (p.o), prior to challenge with maximal electroshock (MES; 180 mA, 220 V, 0.2 s). Apart from observing convulsions, hippocampal mTOR, IL-1β, IL-6 and TNF-α levels were measured. Hippocampal histomorphological analysis was also conducted. In vitro cell line studies and molecular docking studies were run in parallel. The results revealed the synergistic potential of the novel duo-drug combination regimen: PHT (20 mg/kg) and THQ (40 mg/kg) against MES-induced convulsions. MES amplified signaling through mTOR, and inflated the levels of proinflammatory markers (IL-1β, IL-6 and TNF-α), which was significantly averted (p < 0.001) with the said drug combination. The computational studies revealed that PHT and THQ cooperatively bind the active site on Akt (upstream target of m-TOR) and establish a good network of intermolecular interactions, which indicates the sequential inhibition of PI3K/Akt/m-TOR signaling with the combination. The combination also increased cell viability by 242.81% compared to 85.66% viability from the the toxic control. The results suggest that the PHT and THQ in combination possesses excellent anticonvulsant and neuroprotective effects.
Collapse
Affiliation(s)
- Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (F.A.); (M.A.A.D.); (A.F.A.); (H.H.A.)
| | - Mohammed Salahuddin
- Department of Clinical Pharmacy Research, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Firdos Alam Khan
- Department of Stem Cell Research, Institute for Research and Medical Consultations, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Fadhel Alomar
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (F.A.); (M.A.A.D.); (A.F.A.); (H.H.A.)
| | - Marwa Abdullah AL Dhamen
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (F.A.); (M.A.A.D.); (A.F.A.); (H.H.A.)
| | - Abrar Fouad Alhashim
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (F.A.); (M.A.A.D.); (A.F.A.); (H.H.A.)
| | - Hawra Hussain Alqattan
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia; (F.A.); (M.A.A.D.); (A.F.A.); (H.H.A.)
| | - Mohamed S. Gomaa
- Department of Pharmaceutical Chemistry, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia;
| | - Mohammad N. Alomary
- National Centre for Biotechnology, Kind Abdulaziz City for Science and Technology (KACST), P.O. Box 1982, Riyadh 11442, Saudi Arabia
| |
Collapse
|
12
|
Kacsir I, Sipos A, Ujlaki G, Buglyó P, Somsák L, Bai P, Bokor É. Ruthenium Half-Sandwich Type Complexes with Bidentate Monosaccharide Ligands Show Antineoplastic Activity in Ovarian Cancer Cell Models through Reactive Oxygen Species Production. Int J Mol Sci 2021; 22:ijms221910454. [PMID: 34638791 PMCID: PMC8508960 DOI: 10.3390/ijms221910454] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/17/2021] [Accepted: 09/23/2021] [Indexed: 12/16/2022] Open
Abstract
Ruthenium complexes are developed as substitutes for platinum complexes to be used in the chemotherapy of hematological and gynecological malignancies, such as ovarian cancer. We synthesized and screened 14 ruthenium half-sandwich complexes with bidentate monosaccharide ligands in ovarian cancer cell models. Four complexes were cytostatic, but not cytotoxic on A2780 and ID8 cells. The IC50 values were in the low micromolar range (the best being 0.87 µM) and were similar to or lower than those of the clinically available platinum complexes. The active complexes were cytostatic in cell models of glioblastoma, breast cancer, and pancreatic adenocarcinoma, while they were not cytostatic on non-transformed human skin fibroblasts. The bioactive ruthenium complexes showed cooperative binding to yet unidentified cellular target(s), and their activity was dependent on reactive oxygen species production. Large hydrophobic protective groups on the hydroxyl groups of the sugar moiety were needed for biological activity. The cytostatic activity of the ruthenium complexes was dependent on reactive species production. Rucaparib, a PARP inhibitor, potentiated the effects of ruthenium complexes.
Collapse
Affiliation(s)
- István Kacsir
- Department of Organic Chemistry, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary; (I.K.); (L.S.)
- Doctoral School of Chemistry, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary
| | - Adrienn Sipos
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (A.S.); (G.U.)
| | - Gyula Ujlaki
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (A.S.); (G.U.)
| | - Péter Buglyó
- Department of Inorganic & Analytical Chemistry, Faculty of Sciences and Technology, University of Debrecen, H-4032 Debrecen, Hungary;
| | - László Somsák
- Department of Organic Chemistry, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary; (I.K.); (L.S.)
| | - Péter Bai
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (A.S.); (G.U.)
- NKFIH-DE Lendület Laboratory of Cellular Metabolism, H-4032 Debrecen, Hungary
- Research Center for Molecular Medicine, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
- Correspondence: (P.B.); (É.B.)
| | - Éva Bokor
- Department of Organic Chemistry, University of Debrecen, P.O. Box 400, H-4002 Debrecen, Hungary; (I.K.); (L.S.)
- Correspondence: (P.B.); (É.B.)
| |
Collapse
|
13
|
Majewski G, Craw J, Falla T. Accelerated Barrier Repair in Human Skin Explants Induced with a Plant-Derived PPAR-α Activating Complex via Cooperative Interactions. Clin Cosmet Investig Dermatol 2021; 14:1271-1293. [PMID: 34566418 PMCID: PMC8458040 DOI: 10.2147/ccid.s325967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/28/2021] [Indexed: 12/27/2022]
Abstract
Background Peroxisome proliferator-activated receptors (PPARs) govern epidermal lipid synthesis and metabolism. In skin, PPAR activation has been shown to regulate genes responsible for permeability barrier homeostasis, epidermal differentiation, lipid biosynthesis, and inflammation. Objective Given the known dermatologic benefits of PPARs, we set out to discover a naturally derived, multi-molecule complex that would be superior to the more commonly formulated conjugated linoleic acids (CLAs). We hypothesized that a complex may be capable of modulating PPAR-α by cooperative or multi-ligand binding interactions to accelerate skin barrier repair. Methods To achieve this, we assembled a novel PPAR-α agonist complex, referred to as RFV3, from a combination of small molecules routinely used in Ayurvedic medicine and accepted in cosmetic and topical over-the-counter dermatologic products. We tested RFV3’s potential as a PPAR-α agonist by evaluating its transcriptional response, ligand binding affinity to PPAR-α, gene expression profiles and barrier repair properties in human skin explant models. Results We assembled RFV3 by solubilizing two standardized plant extracts in a suitable solvent and induced a significant transcriptional response in PPAR-α luciferase reporter assay. Furthermore, transcriptome profiling of RFV3-treated epidermal substitutes revealed expressed genes consistent with known targets of PPAR-α, including those involved in epidermal barrier repair. In addition, in silico modeling demonstrated differential co-binding affinities of RFV3 to PPAR-α compared with those of the endogenous ligands (CLAs) and a synthetic PPAR-α agonist. Lastly, delipidated skin explant models confirmed accelerated barrier repair activity with significant increases in ceramides, filaggrin and transglutaminase-1 after treatment. Conclusion These findings suggest that the RFV3 complex successfully mimics a PPAR-α agonist and induces synthesis of skin barrier lipids and proteins consistent with known PPAR pathways.
Collapse
Affiliation(s)
- George Majewski
- Rodan & Fields, San Francisco, CA, 94105, USA.,Present Affiliation: Contrast Product Development, Walnut, CA, 91789, USA
| | - John Craw
- Rodan & Fields, San Francisco, CA, 94105, USA
| | | |
Collapse
|
14
|
Guerrero-Santoro J, Khor JM, Açıkbaş AH, Jaynes JB, Ettensohn CA. Analysis of the DNA-binding properties of Alx1, an evolutionarily conserved regulator of skeletogenesis in echinoderms. J Biol Chem 2021; 297:100901. [PMID: 34157281 PMCID: PMC8319359 DOI: 10.1016/j.jbc.2021.100901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 06/09/2021] [Accepted: 06/18/2021] [Indexed: 11/24/2022] Open
Abstract
Alx1, a homeodomain-containing transcription factor, is a highly conserved regulator of skeletogenesis in echinoderms. In sea urchins, Alx1 plays a central role in the differentiation of embryonic primary mesenchyme cells (PMCs) and positively regulates the transcription of most biomineralization genes expressed by these cells. The alx1 gene arose via duplication and acquired a skeletogenic function distinct from its paralog (alx4) through the exonization of a 41–amino acid motif (the D2 domain). Alx1 and Alx4 contain glutamine-50 paired-type homeodomains, which interact preferentially with palindromic binding sites in vitro. Chromatin immunoprecipitation sequencing (ChIP-seq) studies have shown, however, that Alx1 binds both to palindromic and half sites in vivo. To address this apparent discrepancy and explore the function of the D2 domain, we used an endogenous cis-regulatory module associated with Sp-mtmmpb, a gene that encodes a PMC-specific metalloprotease, to analyze the DNA-binding properties of Alx1. We find that Alx1 forms dimeric complexes on TAAT-containing half sites by a mechanism distinct from the well-known mechanism of dimerization on palindromic sites. We used transgenic reporter assays to analyze the functional roles of half sites in vivo and demonstrate that two sites with partially redundant functions are essential for the PMC-specific activity of the Sp-mtmmpb cis-regulatory module. Finally, we show that the D2 domain influences the DNA-binding properties of Alx1 in vitro, suggesting that the exonization of this motif may have facilitated the acquisition of new transcriptional targets and consequently a novel developmental function.
Collapse
Affiliation(s)
| | - Jian Ming Khor
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Ayşe Haruka Açıkbaş
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - James B Jaynes
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
| |
Collapse
|
15
|
Sun Q, Song Y, Aguila B, Ivanov AS, Bryantsev VS, Ma S. Spatial Engineering Direct Cooperativity between Binding Sites for Uranium Sequestration. Adv Sci (Weinh) 2021; 8:2001573. [PMID: 33510996 PMCID: PMC7816700 DOI: 10.1002/advs.202001573] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/26/2020] [Indexed: 05/05/2023]
Abstract
Preorganization is a basic design principle used by nature that allows for synergistic pathways to be expressed. Herein, a full account of the conceptual and experimental development from randomly distributed functionalities to a convergent arrangement that facilitates cooperative binding is given, thus conferring exceptional affinity toward the analyte of interest. The resulting material with chelating groups populated adjacently in a spatially locked manner displays up to two orders of magnitude improvement compared to a random and isolated manner using uranium sequestration as a model application. This adsorbent shows exceptional extraction efficiencies, capable of reducing the uranium concentration from 5 ppm to less than 1 ppb within 10 min, even though the system is permeated with high concentrations of competing ions. The efficiency is further supported by its ability to extract uranium from seawater with an uptake capability of 5.01 mg g-1, placing it among the highest-capacity seawater uranium extraction materials described to date. The concept presented here uncovers a new paradigm in the design of efficient sorbent materials by manipulating the spatial distribution to amplify the cooperation of functions.
Collapse
Affiliation(s)
- Qi Sun
- Department of ChemistryUniversity of South Florida4202 E. Fowler AvenueTampaFL33620USA
| | - Yanpei Song
- Department of ChemistryUniversity of North Texas1508 W Mulberry StDentonTX76201USA
| | - Briana Aguila
- Department of ChemistryUniversity of South Florida4202 E. Fowler AvenueTampaFL33620USA
| | - Aleksandr S. Ivanov
- Chemical Sciences DivisionOak Ridge National LaboratoryP. O. Box 2008Oak RidgeTN37831USA
| | | | - Shengqian Ma
- Department of ChemistryUniversity of South Florida4202 E. Fowler AvenueTampaFL33620USA
- Department of ChemistryUniversity of North Texas1508 W Mulberry StDentonTX76201USA
| |
Collapse
|
16
|
Abstract
Genomics data are now being generated at large quantities, of exquisite high resolution and from single cells. They offer a unique opportunity to develop powerful machine learning algorithms, including neural networks, to uncover the rules of the cis-regulatory code. However, current modeling assumptions are often not based on state-of-the-art knowledge of the cis-regulatory code from transcription, developmental genetics, imaging and structural studies. Here I aim to fill this gap by giving a brief historical overview of the field, describing common misconceptions and providing knowledge that might help to guide computational approaches. I will describe the principles and mechanisms involved in the combinatorial requirement of transcription factor binding motifs for enhancer activity, including the role of chromatin accessibility, repressors and low-affinity motifs in the cis-regulatory code. Deciphering the cis-regulatory code would unlock an enormous amount of regulatory information in the genome and would allow us to locate cis-regulatory genetic variants involved in development and disease.
Collapse
Affiliation(s)
- Julia Zeitlinger
- Stowers Institute for Medical Research, Kansas City, MO, USA
- The University of Kansas Medical Center, Kansas City, KS, USA
| |
Collapse
|
17
|
Li S, Zheng EB, Zhao L, Liu S. Nonreciprocal and Conditional Cooperativity Directs the Pioneer Activity of Pluripotency Transcription Factors. Cell Rep 2019; 28:2689-2703.e4. [PMID: 31484078 DOI: 10.1016/j.celrep.2019.07.103] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/24/2019] [Accepted: 07/26/2019] [Indexed: 01/02/2023] Open
Abstract
Cooperative binding of transcription factors (TFs) to chromatin orchestrates gene expression programming and cell fate specification. However, the biophysical principles of TF cooperativity remain incompletely understood. Here we use single-molecule fluorescence microscopy to study the partnership between Sox2 and Oct4, two core members of the pluripotency gene regulatory network. We find that the ability of Sox2 to target DNA inside nucleosomes is strongly affected by the translational and rotational positioning of its binding motif. In contrast, Oct4 can access nucleosomal sites with equal capacities. Furthermore, the Sox2-Oct4 pair displays nonreciprocal cooperativity, with Oct4 modulating interaction of Sox2 with the nucleosome but not vice versa. Such cooperativity is conditional upon the composite motif’s residing at specific nucleosomal locations. These results reveal that pioneer factors possess distinct chromatin-binding properties and suggest that the same set of TFs can differentially regulate gene activities on the basis of their motif positions in the nucleosomal context. Using single-molecule fluorescence imaging, Li et al. investigate the pioneer activities of pluripotency factors Sox2 and Oct4 and find that they exhibit distinct nucleosome binding preferences as well as context-dependent cooperativity, which potentially allows gene-specific transcriptional regulation.
Collapse
|
18
|
Abstract
The negative regulator of G-protein signalling 4 (Rgs4) is linked to several neurologic diseases, e.g. schizophrenia, addiction, seizure and pain perception. Consequently, Rgs4 expression is tightly regulated, resulting in high mRNA and protein turnover. The post-transcriptional control of gene expression is mediated via RNA-binding proteins (RBPs) that interact with mRNAs in a combinatorial fashion. Here, we show that in neurons the RBP HuR reduces endogenous Rgs4 expression by destabilizing Rgs4 mRNA. Interestingly, in smooth muscle cells, Rgs4 is stabilized by HuR, indicating tissue-dependent differences in HuR function. Using in vitro RNA-based pulldown experiments, we identify the functional AU-rich element (ARE) within the Rgs4 3ʹ-UTR that is recognized and bound by HuR. Bioinformatic analysis uncovered that this ARE lies within a highly conserved area next to a miR-26 binding site. We find that the neuronal-enriched miR-26 negatively influences Rgs4 expression in neurons. Further, HuR and miR-26 act synergistically in fluorescent reporter assays. Together, our data suggest a regulatory mechanism, in which an RBP selectively destabilizes a target mRNA in cooperation with a miRNA and the RISC machinery.
Collapse
Affiliation(s)
- Janina Ehses
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| | - Sandra M Fernández-Moya
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| | - Luise Schröger
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| | - Michael A Kiebler
- BioMedical Center, Medical Faculty, Ludwig Maximilians University of Munich, Martinsried, Germany
| |
Collapse
|
19
|
Zeiske T, Baburajendran N, Kaczynska A, Brasch J, Palmer AG, Shapiro L, Honig B, Mann RS. Intrinsic DNA Shape Accounts for Affinity Differences between Hox-Cofactor Binding Sites. Cell Rep 2020; 24:2221-2230. [PMID: 30157419 DOI: 10.1016/j.celrep.2018.07.100] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/14/2018] [Accepted: 07/28/2018] [Indexed: 11/26/2022] Open
Abstract
Transcription factors bind to their binding sites over a wide range of affinities, yet how differences in affinity are encoded in DNA sequences is not well understood. Here, we report X-ray crystal structures of four heterodimers of the Hox protein AbdominalB bound with its cofactor Extradenticle to four target DNA molecules that differ in affinity by up to ∼20-fold. Remarkably, despite large differences in affinity, the overall structures are very similar in all four complexes. In contrast, the predicted shapes of the DNA binding sites (i.e., the intrinsic DNA shape) in the absence of bound protein are strikingly different from each other and correlate with affinity: binding sites that must change conformations upon protein binding have lower affinities than binding sites that have more optimal conformations prior to binding. Together, these observations suggest that intrinsic differences in DNA shape provide a robust mechanism for modulating affinity without affecting other protein-DNA interactions.
Collapse
Affiliation(s)
- Tim Zeiske
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Nithya Baburajendran
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Anna Kaczynska
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Julia Brasch
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Arthur G Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA; Department of Systems Biology, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| | - Richard S Mann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA; Department of Systems Biology, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| |
Collapse
|
20
|
Gomes AM, Kurochkin I, Chang B, Daniel M, Law K, Satija N, Lachmann A, Wang Z, Ferreira L, Ma'ayan A, Chen BK, Papatsenko D, Lemischka IR, Moore KA, Pereira CF. Cooperative Transcription Factor Induction Mediates Hemogenic Reprogramming. Cell Rep 2019; 25:2821-2835.e7. [PMID: 30517869 PMCID: PMC6571141 DOI: 10.1016/j.celrep.2018.11.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 08/19/2018] [Accepted: 10/24/2018] [Indexed: 12/11/2022] Open
Abstract
During development, hematopoietic stem and progenitor cells (HSPCs) arise from specialized endothelial cells by a process termed endothelial-to-hematopoietic transition (EHT). The genetic program driving human HSPC emergence remains largely unknown. We previously reported that the generation of hemogenic precursor cells from mouse fibroblasts recapitulates developmental hematopoiesis. Here, we demonstrate that human fibroblasts can be reprogrammed into hemogenic cells by the same transcription factors. Induced cells display dynamic EHT transcriptional programs, generate hematopoietic progeny, possess HSPC cell surface phenotype, and repopulate immunodeficient mice for 3 months. Mechanistically, GATA2 and GFI1B interact and co-occupy a cohort of targets. This cooperative binding is reflected by engagement of open enhancers and promoters, initiating silencing of fibroblast genes and activating the hemogenic program. However, GATA2 displays dominant and independent targeting activity during the early phases of reprogramming. These findings shed light on the processes controlling human HSC specification and support generation of reprogrammed HSCs for clinical applications. Gomes et al. show that specification of hemogenesis in human fibroblasts is mediated by cooperative transcription factor binding. GATA2 displays dominance, interacts with GFI1B, and recruits FOS to open chromatin, simultaneously silencing the fibroblast program and initiating an endothelial-to-hematopoietic transition to definitive hematopoiesis.
Collapse
Affiliation(s)
- Andreia M Gomes
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Doctoral Programme in Experimental Biology and Biomedicine, University of Coimbra, Largo Marquês do Pombal 3004-517, Coimbra, Portugal; Centre for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês do Pombal 3004-517, Coimbra, Portugal
| | - Ilia Kurochkin
- Skolkovo Institute of Science and Technology, Nobel Street, Building 3, Moscow 143026, Russia
| | - Betty Chang
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Michael Daniel
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Kenneth Law
- Division of Infectious Disease, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Namita Satija
- Division of Infectious Disease, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Alexander Lachmann
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Zichen Wang
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Lino Ferreira
- Centre for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês do Pombal 3004-517, Coimbra, Portugal
| | - Avi Ma'ayan
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Benjamin K Chen
- Division of Infectious Disease, Department of Medicine, Immunology Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Dmitri Papatsenko
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Skolkovo Institute of Science and Technology, Nobel Street, Building 3, Moscow 143026, Russia
| | - Ihor R Lemischka
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA
| | - Kateri A Moore
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1496, New York, NY 10029, USA.
| | - Carlos-Filipe Pereira
- Centre for Neuroscience and Cell Biology, University of Coimbra, Largo Marquês do Pombal 3004-517, Coimbra, Portugal; Molecular Medicine and Gene Therapy, Lund Stem Cell Centre, Lund University, BMC A12, 221 84, Lund, Sweden; Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden.
| |
Collapse
|
21
|
Luo J, Zhu J, Tuo DH, Yuan Q, Wang L, Wang XB, Ao YF, Wang QQ, Wang DX. Macrocycle-Directed Construction of Tetrahedral Anion-π Receptors for Nesting Anions with Complementary Geometry. Chemistry 2019; 25:13275-13279. [PMID: 31398268 DOI: 10.1002/chem.201903272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/07/2019] [Indexed: 12/19/2022]
Abstract
Manipulation of the emerging anion-π interactions in a highly cooperative manner through sophisticated host design represents a very challenging task. In this work, unprecedented tetrahedral anion-π receptors have been successfully constructed for complementary accommodation of tetrahedral and relevant anions. The synthesis was achieved by a macrocycle-directed approach by using large macrocycle precursors bearing four reactive sites, which enabled a kinetic-favored pathway and afforded the otherwise inaccessible tetrahedral cages in considerable yields. Crystal structure suggested that the tetrahedral cages have an enclosed three-dimensional cavity surrounded by four electron-deficient triazine faces in a tetrahedral array. The complementary accommodation of a series of tetrahedral and relevant anions including BF4 - , ClO4 - , H2 PO4 - , HSO4 - , SO4 2- and PF6 - was revealed by ESI-MS and DFT calculations. Crystal structures of ClO4 - and PF6 - complexes showed that the anion was nicely encapsulated within the tetrahedral cavity with up to quadruple cooperative anion-π interactions by an excellent shape and size match. The strong anion-π binding was further confirmed by negative ion photoelectron spectroscopy measurements.
Collapse
Affiliation(s)
- Jian Luo
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Jun Zhu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - De-Hui Tuo
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Qinqin Yuan
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington, 99352, USA
| | - Lei Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington, 99352, USA
| | - Xue-Bin Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington, 99352, USA
| | - Yu-Fei Ao
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Qi-Qiang Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - De-Xian Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100190, P. R. China
| |
Collapse
|
22
|
Liu X, Hu Q, Yang J, Huang S, Wei T, Chen W, He Y, Wang D, Liu Z, Wang K, Gan J, Chen H. Selective cadmium regulation mediated by a cooperative binding mechanism in CadR. Proc Natl Acad Sci U S A 2019; 116:20398-403. [PMID: 31548408 DOI: 10.1073/pnas.1908610116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The highly toxic cadmium ion can cause destructive hazards to living systems by nonspecific and tight binding on functional macromolecules. However, most of the developed cadmium detoxification systems are not sufficient to recognize or detoxify cadmium ions, specifically due to the similar coordination behavior of heavy metal ions in thiolate-rich sites. Here we report that the ultraspecific cadmium regulator CadR has evolved 2 distinct types of functional recognition sites rather than a mono-type thiolate-rich site to achieve outstanding selectivity. The thiolate-rich site I and the adjacent histidine-rich recognition site II are highly associated with transcription activation. This cooperative binding mechanism could improve our understanding of the relationship between the structural dynamics and biological function of metalloregulators. Detoxification of the highly toxic cadmium element is essential for the survival of living organisms. Pseudomonas putida CadR, a MerR family transcriptional regulator, has been reported to exhibit an ultraspecific response to the cadmium ion. Our crystallographic and spectroscopic studies reveal that the extra cadmium selectivity of CadR is mediated by the unexpected cooperation of thiolate-rich site I and histidine-rich site II. Cadmium binding in site I mediates the reorientation of protein domains and facilitates the assembly of site II. Subsequently, site II bridge-links 2 DNA binding domains through ligands His140/His145 in the C-terminal histidine-rich tail. With dynamic transit between 2 conformational states, this bridge could stabilize the regulator into an optimal conformation that is critical for enhancing the transcriptional activity of the cadmium detoxification system. Our results provide dynamic insight into how nature utilizes the unique cooperative binding mechanism in multisite proteins to recognize cadmium ions specifically.
Collapse
|
23
|
Wang L, Gaigalas AK, DeRose PC. A Model for the Binding of Fluorescently Labeled Anti-Human CD4 Monoclonal Antibodies to CD4 Receptors on Human Lymphocytes. J Res Natl Inst Stand Technol 2018; 123:1-23. [PMID: 34877142 PMCID: PMC7339780 DOI: 10.6028/jres.123.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/07/2018] [Indexed: 06/13/2023]
Abstract
The CD4 glycoprotein is a component of the T cell receptor complex which plays an important role in the human immune response. This manuscript describes the measurement and modeling of the binding of fluorescently labeled anti-human CD4 monoclonal antibodies (mAb; SK3 clone) to CD4 receptors on the surface of human peripheral blood mononuclear cells (PBMC). CD4 mAb fluorescein isothiocyanate (FITC) and CD4 mAb allophycoerythrin (APC) conjugates were obtained from commercial sources. Four binding conditions were performed, each with the same PBMC sample and different CD4 mAb conjugate. Each binding condition consisted of the PBMC sample incubated for 30 min in labeling solutions containing progressively larger concentrations of the CD4 mAb-label conjugate. After the incubation period, the cells were re-suspended in PBS-based buffer and analyzed using a flow cytometer to measure the mean fluorescence intensity (MFI) of the labeled cell populations. A model was developed to estimate the equilibrium concentration of bound CD4 mAb-label conjugates to CD4 receptors on PBMC. A set of parameters was obtained from the best fit of the model to the measured MFI data and the known number of CD4 receptors on PBMC surface. Divalent and monovalent binding had to be invoked for the APC and FITC CD4 mAb conjugates, respectively. This suggests that the mAb binding depends on the size of the label, which has significant implications for quantitative flow cytometry. The study supports the National Institute of Standards and Technology program to develop quantitative flow cytometry measurements.
Collapse
Affiliation(s)
- Lili Wang
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | | | - Paul C DeRose
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| |
Collapse
|
24
|
Chen WF, Wei XB, Rety S, Huang LY, Liu NN, Dou SX, Xi XG. Structural analysis reveals a "molecular calipers" mechanism for a LATERAL ORGAN BOUNDARIES DOMAIN transcription factor protein from wheat. J Biol Chem 2018; 294:142-156. [PMID: 30425099 DOI: 10.1074/jbc.ra118.003956] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/10/2018] [Indexed: 01/13/2023] Open
Abstract
LATERAL ORGAN BOUNDARIES DOMAIN (LBD) proteins, a family of plant-specific transcription factors harboring a conserved Lateral Organ Boundaries (LOB) domain, are regulators of plant organ development. Recent studies have unraveled additional pivotal roles of the LBD protein family beyond defining lateral organ boundaries, such as pollen development and nitrogen metabolism. The structural basis for the molecular network of LBD-dependent processes remains to be deciphered. Here, we solved the first structure of the homodimeric LOB domain of Ramosa2 from wheat (TtRa2LD) to 1.9 Å resolution. Our crystal structure reveals structural features shared with other zinc-finger transcriptional factors, as well as some features unique to LBD proteins. Formation of the TtRa2LD homodimer relied on hydrophobic interactions of its coiled-coil motifs. Several specific motifs/domains of the LBD protein were also involved in maintaining its overall conformation. The intricate assembly within and between the monomers determined the precise spatial configuration of the two zinc fingers that recognize palindromic DNA sequences. Biochemical, molecular modeling, and small-angle X-ray scattering experiments indicated that dimerization is important for cooperative DNA binding and discrimination of palindromic DNA through a molecular calipers mechanism. Along with previously published data, this study enables us to establish an atomic-scale mechanistic model for LBD proteins as transcriptional regulators in plants.
Collapse
Affiliation(s)
- Wei-Fei Chen
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiao-Bin Wei
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China; School of Life Science and Engineering, Henan University of Urban Construction, Pingdingshan, Henan, 467044, China
| | - Stephane Rety
- University Lyon, ENS de Lyon, University Claude Bernard, CNRS UMR 5239, INSERM U1210, LBMC, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France.
| | - Ling-Yun Huang
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Na-Nv Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Shuo-Xing Dou
- Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xu-Guang Xi
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China; LBPA, Ecole Normale Supérieure Paris-Saclay, CNRS, Université Paris Saclay, 61 Avenue du Président Wilson, F-94235 Cachan, France.
| |
Collapse
|
25
|
Carreira-Barral I, Fernández-Pérez I, Mato-Iglesias M, de Blas A, Platas-Iglesias C, Esteban-Gómez D. Recognition of AMP, ADP and ATP through Cooperative Binding by Cu(II) and Zn(II) Complexes Containing Urea and/or Phenylboronic-Acid Moieties. Molecules 2018; 23:molecules23020479. [PMID: 29470445 PMCID: PMC6017333 DOI: 10.3390/molecules23020479] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 02/16/2018] [Accepted: 02/20/2018] [Indexed: 12/16/2022] Open
Abstract
We report a series of Cu(II) and Zn(II) complexes with different ligands containing a dipicolyl unit functionalized with urea groups that may contain or not a phenylboronic acid function. These complexes were designed for the recognition of phosphorylated anions through coordination to the metal ion reinforced by hydrogen bonds involving the anion and NH groups of urea. The complexes were isolated and several adducts with pyrophosphate were characterized using X-ray diffraction measurements. Coordination of one of the urea nitrogen atoms to the metal ion promoted the hydrolysis of the ligands containing 1,3-diphenylurea units, while ligands bearing 1-ethyl-3-phenylurea groups did not hydrolyze significantly at room temperature. Spectrophotometric titrations, combined with 1H and 31P NMR studies, were used in investigating the binding of phosphate, pyrophosphate (PPi), and nucleoside 5′-polyphosphates (AMP, ADP, ATP, CMP, and UMP). The association constants determined in aqueous solution (pH 7.0, 0.1 M MOPS) point to a stronger association with PPi, ADP, and ATP as compared with the anions containing a single phosphate unit. The [CuL4]2+ complex shows important selectivity for pyrophosphate (PPi) over ADP and ATP.
Collapse
Affiliation(s)
- Israel Carreira-Barral
- Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA), 15071 A Coruña, Galicia, Spain.
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, 09001 Burgos, Spain.
| | - Isabel Fernández-Pérez
- Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA), 15071 A Coruña, Galicia, Spain.
| | - Marta Mato-Iglesias
- Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA), 15071 A Coruña, Galicia, Spain.
| | - Andrés de Blas
- Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA), 15071 A Coruña, Galicia, Spain.
| | - Carlos Platas-Iglesias
- Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA), 15071 A Coruña, Galicia, Spain.
| | - David Esteban-Gómez
- Departamento de Química, Facultade de Ciencias, Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA), 15071 A Coruña, Galicia, Spain.
| |
Collapse
|
26
|
Deakyne JS, Malecka KA, Messick TE, Lieberman PM. Structural and Functional Basis for an EBNA1 Hexameric Ring in Epstein-Barr Virus Episome Maintenance. J Virol 2017; 91:e01046-17. [PMID: 28701406 DOI: 10.1128/JVI.01046-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/09/2017] [Indexed: 12/14/2022] Open
Abstract
Epstein-Barr virus (EBV) establishes a stable latent infection that can persist for the life of the host. EBNA1 is required for the replication, maintenance, and segregation of the latent episome, but the structural features of EBNA1 that confer each of these functions are not completely understood. Here, we have solved the X-ray crystal structure of an EBNA1 DNA-binding domain (DBD) and discovered a novel hexameric ring oligomeric form. The oligomeric interface pivoted around residue T585 as a joint that links and stabilizes higher-order EBNA1 complexes. Substitution mutations around the interface destabilized higher-order complex formation and altered the cooperative DNA-binding properties of EBNA1. Mutations had both positive and negative effects on EBNA1-dependent DNA replication and episome maintenance with OriP. We found that one naturally occurring polymorphism in the oligomer interface (T585P) had greater cooperative DNA binding in vitro, minor defects in DNA replication, and pronounced defects in episome maintenance. The T585P mutant was compromised for binding to OriP in vivo as well as for assembling the origin recognition complex subunit 2 (ORC2) and trimethylated histone 3 lysine 4 (H3K4me3) at OriP. The T585P mutant was also compromised for forming stable subnuclear foci in living cells. These findings reveal a novel oligomeric structure of EBNA1 with an interface subject to naturally occurring polymorphisms that modulate EBNA1 functional properties. We propose that EBNA1 dimers can assemble into higher-order oligomeric structures important for diverse functions of EBNA1.IMPORTANCE Epstein-Barr virus is a human gammaherpesvirus that is causally associated with various cancers. Carcinogenic properties are linked to the ability of the virus to persist in the latent form for the lifetime of the host. EBNA1 is a sequence-specific DNA-binding protein that is consistently expressed in EBV tumors and is the only viral protein required to maintain the viral episome during latency. The structural and biochemical mechanisms by which EBNA1 allows the long-term persistence of the EBV genome are currently unclear. Here, we have solved the crystal structure of an EBNA1 hexameric ring and characterized key residues in the interface required for higher-order complex formation and long-term plasmid maintenance.
Collapse
|
27
|
Piechowicz M, Abney CW, Thacker NC, Gilhula JC, Wang Y, Veroneau SS, Hu A, Lin W. Successful Coupling of a Bis-Amidoxime Uranophile with a Hydrophilic Backbone for Selective Uranium Sequestration. ACS Appl Mater Interfaces 2017; 9:27894-27904. [PMID: 28752756 DOI: 10.1021/acsami.7b04656] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The amidoxime group (-RNH2NOH) has long been used to extract uranium from seawater on account of its high affinity toward uranium. The development of tunable sorbent materials for uranium sequestration remains a research priority as well as a significant challenge. Herein, we report the design, synthesis, and uranium sorption properties of bis-amidoxime-functionalized polymeric materials (BAP 1-3). Bifunctional amidoxime monomers were copolymerized with an acrylamide cross-linker to obtain bis-amidoxime incorporation as high as 2 mmol g-1 after five synthetic steps. The resulting sorbents were able to uptake nearly 600 mg of uranium per gram of polymer after 37 days of contact with a seawater simulant containing 8 ppm uranium. Moreover, the polymeric materials exhibited low vanadium uptake with a maximum capacity of 128 mg of vanadium per gram of polymer. This computationally predicted and experimentally realized selectivity of uranium over vanadium, nearly 5 to 1 w/w, is one of the highest reported to date and represents an advancement in the rational design of sorbent materials with high uptake capacity and selectivity.
Collapse
Affiliation(s)
- Marek Piechowicz
- Department of Chemistry, University of Chicago , 929 E. 57th Street, Chicago, Illinois 60637, United States
| | - Carter W Abney
- Oak Ridge National Laboratory , P.O. Box 2008, MS-6201, Oak Ridge, Tennessee 37831-6181, United States
| | - Nathan C Thacker
- Department of Chemistry, University of Chicago , 929 E. 57th Street, Chicago, Illinois 60637, United States
| | - James C Gilhula
- Department of Chemistry, University of Chicago , 929 E. 57th Street, Chicago, Illinois 60637, United States
| | - Youfu Wang
- Department of Chemistry, University of Chicago , 929 E. 57th Street, Chicago, Illinois 60637, United States
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology , Shanghai 200237, China
| | - Samuel S Veroneau
- Department of Chemistry, University of Chicago , 929 E. 57th Street, Chicago, Illinois 60637, United States
| | - Aiguo Hu
- Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology , Shanghai 200237, China
| | - Wenbin Lin
- Department of Chemistry, University of Chicago , 929 E. 57th Street, Chicago, Illinois 60637, United States
| |
Collapse
|
28
|
Mallagaray A, Rademacher C, Parra F, Hansman G, Peters T. Saturation transfer difference nuclear magnetic resonance titrations reveal complex multistep-binding of l-fucose to norovirus particles. Glycobiology 2016; 27:80-86. [PMID: 27496762 DOI: 10.1093/glycob/cww070] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/24/2016] [Accepted: 06/25/2016] [Indexed: 01/20/2023] Open
Abstract
Recently, combined nuclear magnetic resonance (NMR), native mass spectrometry (MS) and X-ray crystallographic studies have demonstrated that binding of histo-blood group antigens (HBGAs) to norovirus capsid protein (P-dimers) is a cooperative process involving four binding pockets. Here, we show that binding to norovirus virus-like particles (VLPs) is even more complex. We performed saturation transfer difference (STD) NMR titration experiments with two representative genotypes of norovirus VLPs using l-fucose as a minimal HBGA. Compared to titrations with P-dimers, the corresponding binding isotherms reflect at least six distinct binding events.
Collapse
Affiliation(s)
- Alvaro Mallagaray
- Center of Structural and Cell Biology in Medicine, Institute of Chemistry, University of Luebeck, Ratzeburger Allee 160, 23562 Luebeck, Germany
| | - Christoph Rademacher
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Francisco Parra
- Universidad de Oviedo, Instituto Universitario de Biotecnología de Asturias, 33006 Oviedo Spain
| | - Grant Hansman
- Schaller Research Group at the University of Heidelberg and the DKFZ, 69120 Heidelberg, Germany.,Department of Infectious Diseases and Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Thomas Peters
- Center of Structural and Cell Biology in Medicine, Institute of Chemistry, University of Luebeck, Ratzeburger Allee 160, 23562 Luebeck, Germany
| |
Collapse
|
29
|
Zha D, You L. Multiresponsive Dynamic Covalent Assemblies for the Selective Sensing of Both Cu(2+) and CN(-) in Water. ACS Appl Mater Interfaces 2016; 8:2399-2405. [PMID: 26720908 DOI: 10.1021/acsami.5b11552] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The use of dynamic assembly for molecular sensing is an intensive area of research in supramolecular chemistry. However, the development of self-assembly architectures for the detection of multiple signals remains challenging. Here, we present dynamic covalent assemblies with multiresponsive properties that also show unique selectivity profiles in water. The receptors were generated in a single step with modularly designed building blocks through acylhydrazone linkages, and their orthogonal assembly with a series of external stimuli was investigated. Notably, the system exhibits responses toward cations, anions, solvents, pH, and amphiphilicity. The discrimination of Cu(2+) from other divalent metal ions was achieved by simply changing the solvent and was evidenced by a Cu(2+)-induced pKa shift. The selective recognition of CN(-) in pure aqueous media was also accomplished through a cooperative effect in conjunction with Zn(2+). Furthermore, the assembly and its responsiveness are functional both in solution and the solid state. The aggregation ability of these dynamic covalent systems supports their binding and sensing properties.
Collapse
Affiliation(s)
- Daijun Zha
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 35002, P. R. China
| | - Lei You
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 35002, P. R. China
| |
Collapse
|
30
|
Abstract
We have investigated the interaction between the native neutral β-cyclodextrin (CD) and the DNA molecule by performing single-molecule stretching experiments with optical tweezers. In particular, we have monitored the changes of the mechanical properties of the CD-DNA complexes as a function of the CD concentration in the sample. By using a quenched disorder statistical model, we were also capable to extract important physicochemical information (equilibrium binding constants, cooperativity degree) of such interaction from the mechanical data. In addition, we have found that the interaction occurs by two different mechanisms, first with the formation of relatively large CD clusters along the double helix, which thereafter can locally denature the DNA molecule by forming hydrogen bonds with the base pairs that eventually flip out. A prediction of our quenched disorder model was that cooperativity could be controlled by adjusting the surface charge of β-CD molecules. This prediction is confirmed in the present work.
Collapse
Affiliation(s)
- P S Alves
- Departamento de Física, Universidade Federal de Minas Gerais , Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - O N Mesquita
- Departamento de Física, Universidade Federal de Minas Gerais , Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - M S Rocha
- Departamento de Física, Universidade Federal de Viçosa , Av. P. H. Rolfs s/n, Viçosa, Minas Gerais 36570-900, Brazil
| |
Collapse
|
31
|
Mallagaray A, Lockhauserbäumer J, Hansman G, Uetrecht C, Peters T. Attachment of norovirus to histo blood group antigens: a cooperative multistep process. Angew Chem Int Ed Engl 2015; 54:12014-9. [PMID: 26329854 DOI: 10.1002/anie.201505672] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Indexed: 11/11/2022]
Abstract
Human noroviruses recognize histo blood group antigens (HBGAs) as cellular attachment factors. Recently, it has been discovered that norovirus infection can be significantly enhanced by HBGA binding. Yet the attachment process and how it promotes host-cell entry is only poorly understood. The binding of a norovirus protruding (P) domain of a predominant GII.4 Saga strain to HBGAs at atomic resolution was studied. So far, independent and equivalent multiple binding sites were held responsible for attachment. Using NMR experiments we show that norovirus-HBGA binding is a cooperative multi-step process, and native mass spectrometry reveals four instead of two HBGA binding sites per P-dimer. An accompanying crystallographic study has disclosed four instead of two L-fucose binding sites per P-dimer of a related GII.10 strain1 further supporting our findings. We have uncovered a novel paradigm for norovirus-HBGA recognition that will inspire further studies into norovirus-host interactions.
Collapse
Affiliation(s)
- Alvaro Mallagaray
- Center of Structural and Cell Biology in Medicine, Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck (Germany)
| | - Julia Lockhauserbäumer
- Dynamics of Viral Structures, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistrasse 52, 20251 Hamburg (Germany).,Sample Environment Group, European XFEL GmbH, Notkestrasse 85, 22607 Hamburg (Germany)
| | - Grant Hansman
- Schaller Research Group at the University of Heidelberg and the DKFZ, 69120 Heidelberg (Germany).,Department of Infectious Diseases and Virology, University of Heidelberg, 69120 Heidelberg (Germany)
| | - Charlotte Uetrecht
- Dynamics of Viral Structures, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistrasse 52, 20251 Hamburg (Germany).,Sample Environment Group, European XFEL GmbH, Notkestrasse 85, 22607 Hamburg (Germany)
| | - Thomas Peters
- Center of Structural and Cell Biology in Medicine, Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck (Germany).
| |
Collapse
|
32
|
Abstract
Both RNA-binding proteins (RBP) and miRNA play important roles in the regulation of mRNA expression, often acting together to regulate a target mRNA. In some cases the RBP and miRNA have been reported to act competitively, but in other instances they function cooperatively. Here, we investigated HuR function as an enhancer of let-7-mediated translational repression of c-Myc despite the separation of their binding sites. Using an in vitro system, we determined that a let-7 mimic, consisting of single-stranded (ss)DNA complementary to the let-7 binding site, enhanced the affinity of HuR for a 122-nt MYC RNA encompassing both binding sites. This finding supports the biophysical principle of cooperative binding by an RBP and miRNA purely through interactions at distal mRNA binding sites.
Collapse
Affiliation(s)
- Menachem J Gunzburg
- a Biochemistry and Molecular Biology; Monash University ; Melbourne , VIC Australia
| | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Interactions mediated by short linear motifs in proteins play major roles in regulation of cellular homeostasis since their transient nature allows for easy modulation. We are still far from a full understanding and appreciation of the complex regulation patterns that can be, and are, achieved by this type of interaction. The fact that many linear-motif-binding domains occur in tandem repeats in proteins indicates that their mutual communication is used extensively to obtain complex integration of information toward regulatory decisions. This review is an attempt to overview, and classify, different ways by which two and more tandem repeats cooperate in binding to their targets, in the well-characterized family of WW domains and their corresponding polyproline ligands.
Collapse
Affiliation(s)
- Emma Joy Dodson
- Department of Microbiology and Molecular Genetics, Institute of Biomedical Research Israel-Canada IMRIC, Faculty of Medicine, Ein Kerem Campus, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| | - Vered Fishbain-Yoskovitz
- Department of Microbiology and Molecular Genetics, Institute of Biomedical Research Israel-Canada IMRIC, Faculty of Medicine, Ein Kerem Campus, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| | - Shahar Rotem-Bamberger
- Department of Microbiology and Molecular Genetics, Institute of Biomedical Research Israel-Canada IMRIC, Faculty of Medicine, Ein Kerem Campus, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| | - Ora Schueler-Furman
- Department of Microbiology and Molecular Genetics, Institute of Biomedical Research Israel-Canada IMRIC, Faculty of Medicine, Ein Kerem Campus, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
| |
Collapse
|
34
|
Abstract
The distributions of many proteins in rod-shaped bacteria are far from homogeneous. Often they accumulate at the cell poles or in the cell centre. At the same time, the copy number of proteins in a single cell is relatively small making the patterns noisy. To explore limits to protein patterns due to molecular noise, we studied a generic mechanism for spontaneous polar protein assemblies in rod-shaped bacteria, which are based on cooperative binding of proteins to the cytoplasmic membrane. For mono-polar assemblies, we find that the switching time between the two poles increases exponentially with the cell length and with the protein number. This feature could be beneficial to organelle maintenance in ageing bacteria.
Collapse
Affiliation(s)
- L Wettmann
- Theoretische Physik , Universität des Saarlandes , Postfach 151150, 66041 Saarbrücken , Germany
| | - M Bonny
- Theoretische Physik , Universität des Saarlandes , Postfach 151150, 66041 Saarbrücken , Germany
| | - K Kruse
- Theoretische Physik , Universität des Saarlandes , Postfach 151150, 66041 Saarbrücken , Germany
| |
Collapse
|
35
|
Guturu H, Doxey AC, Wenger AM, Bejerano G. Structure-aided prediction of mammalian transcription factor complexes in conserved non-coding elements. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130029. [PMID: 24218641 DOI: 10.1098/rstb.2013.0029] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mapping the DNA-binding preferences of transcription factor (TF) complexes is critical for deciphering the functions of cis-regulatory elements. Here, we developed a computational method that compares co-occurring motif spacings in conserved versus unconserved regions of the human genome to detect evolutionarily constrained binding sites of rigid TF complexes. Structural data were used to estimate TF complex physical plausibility, explore overlapping motif arrangements seldom tackled by non-structure-aware methods, and generate and analyse three-dimensional models of the predicted complexes bound to DNA. Using this approach, we predicted 422 physically realistic TF complex motifs at 18% false discovery rate, the majority of which (326, 77%) contain some sequence overlap between binding sites. The set of mostly novel complexes is enriched in known composite motifs, predictive of binding site configurations in TF-TF-DNA crystal structures, and supported by ChIP-seq datasets. Structural modelling revealed three cooperativity mechanisms: direct protein-protein interactions, potentially indirect interactions and 'through-DNA' interactions. Indeed, 38% of the predicted complexes were found to contain four or more bases in which TF pairs appear to synergize through overlapping binding to the same DNA base pairs in opposite grooves or strands. Our TF complex and associated binding site predictions are available as a web resource at http://bejerano.stanford.edu/complex.
Collapse
Affiliation(s)
- Harendra Guturu
- Department of Electrical Engineering, Stanford University, , Stanford, CA 94305, USA
| | | | | | | |
Collapse
|
36
|
Szent-Gyorgyi C, Stanfield RL, Andreko S, Dempsey A, Ahmed M, Capek S, Waggoner AS, Wilson IA, Bruchez MP. Malachite green mediates homodimerization of antibody VL domains to form a fluorescent ternary complex with singular symmetric interfaces. J Mol Biol 2013; 425:4595-613. [PMID: 23978698 DOI: 10.1016/j.jmb.2013.08.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/15/2013] [Accepted: 08/16/2013] [Indexed: 01/19/2023]
Abstract
We report that a symmetric small-molecule ligand mediates the assembly of antibody light chain variable domains (VLs) into a correspondent symmetric ternary complex with novel interfaces. The L5* fluorogen activating protein is a VL domain that binds malachite green (MG) dye to activate intense fluorescence. Crystallography of liganded L5* reveals a 2:1 protein:ligand complex with inclusive C2 symmetry, where MG is almost entirely encapsulated between an antiparallel arrangement of the two VL domains. Unliganded L5* VL domains crystallize as a similar antiparallel VL/VL homodimer. The complementarity-determining regions are spatially oriented to form novel VL/VL and VL/ligand interfaces that tightly constrain a propeller conformer of MG. Binding equilibrium analysis suggests highly cooperative assembly to form a very stable VL/MG/VL complex, such that MG behaves as a strong chemical inducer of dimerization. Fusion of two VL domains into a single protein tightens MG binding over 1000-fold to low picomolar affinity without altering the large binding enthalpy, suggesting that bonding interactions with ligand and restriction of domain movements make independent contributions to binding. Fluorescence activation of a symmetrical fluorogen provides a selection mechanism for the isolation and directed evolution of ternary complexes where unnatural symmetric binding interfaces are favored over canonical antibody interfaces. As exemplified by L5*, these self-reporting complexes may be useful as modulators of protein association or as high-affinity protein tags and capture reagents.
Collapse
Affiliation(s)
- Chris Szent-Gyorgyi
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Winssinger N. DNA display of PNA-tagged ligands: a versatile strategy to screen libraries and control geometry of multidentate ligands. Artif DNA PNA XNA 2012; 3:105-8. [PMID: 22871882 PMCID: PMC3581508 DOI: 10.4161/adna.21108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Over the past decade, several technologies have emerged to access nucleic acid-tagged libraries and select the fittest compound within such libraries. This perspective focuses on recent development with PNA-tagged small molecules displayed on DNA templates for screening purposes and to probe the optimal geometry in multivalent interactions.
Collapse
Affiliation(s)
- Nicolas Winssinger
- Institut de Science et Ingénierie Supramoléculaires, Université de Strasbourg, CNRS, Strasbourg, France.
| |
Collapse
|
38
|
Zuniga JE, Ilangovan U, Mahlawat P, Hinck CS, Huang T, Groppe JC, McEwen DG, Hinck AP. The TβR-I pre-helix extension is structurally ordered in the unbound form and its flanking prolines are essential for binding. J Mol Biol 2011; 412:601-18. [PMID: 21821041 PMCID: PMC3576881 DOI: 10.1016/j.jmb.2011.07.046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 07/21/2011] [Accepted: 07/21/2011] [Indexed: 11/21/2022]
Abstract
Transforming growth factor β isoforms (TGF-β) are among the most recently evolved members of a signaling superfamily with more than 30 members. TGF-β play vital roles in regulating cellular growth and differentiation, and they signal through a highly restricted subset of receptors known as TGF-β type I receptor (TβR-I) and TGF-β type II receptor (TβR-II). TGF-β's specificity for TβR-I has been proposed to arise from its pre-helix extension, a five-residue loop that binds in the cleft between TGF-β and TβR-II. The structure and backbone dynamics of the unbound form of the TβR-I extracellular domain were determined using NMR to investigate the extension's role in binding. This showed that the unbound form is highly similar to the bound form in terms of both the β-strand framework that defines the three-finger toxin fold and the extension and its characteristic cis-Ile54-Pro55 peptide bond. The NMR data further showed that the extension and two flanking 3(10) helices are rigid on the nanosecond-to-picosecond timescale. The functional significance of several residues within the extension was investigated by binding studies and reporter gene assays in cultured epithelial cells. These demonstrated that the pre-helix extension is essential for binding, with Pro55 and Pro59 each playing a major role. These findings suggest that the pre-helix extension and its flanking prolines evolved to endow the TGF-β signaling complex with its unique specificity, departing from the ancestral promiscuity of the bone morphogenetic protein subfamily, where the binding interface of the type I receptor is highly flexible.
Collapse
Affiliation(s)
- Jorge E. Zuniga
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Departments of Molecular and Cellular Physiology, Neurology and Neurological Science, Structural Biology, and Photon Science, Stanford University, Stanford, CA 94305, USA
| | - Udayar Ilangovan
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Pardeep Mahlawat
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Cynthia S. Hinck
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Tao Huang
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Jay C. Groppe
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Biomedical Sciences, Texas A&M Health Science Center, Dallas, TX 75246, USA
| | - Donald G. McEwen
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Andrew P. Hinck
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| |
Collapse
|
39
|
Lo PK, Wong MS. Extended Calix[4]arene-Based Receptors for Molecular Recognition and Sensing. Sensors (Basel) 2008; 8:5313-5335. [PMID: 27873816 PMCID: PMC3705506 DOI: 10.3390/s8095313] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 08/28/2008] [Accepted: 08/29/2008] [Indexed: 11/16/2022]
Abstract
Recent advances in the area of recognition and sensing have shown that artificial receptors derived from extended calix[4]arenes bearing multiple π-conjugated fluorophoric or chromophoric systems have found useful to enhance binding affinity, selectivity and sensitivity for recognition and sensing of a targeted ion or molecule. A comprehensive review of various π-conjugation-extended calyx[4]arene-based receptors with the highlight on the design and binding characterization for recognition and sensing is presented.
Collapse
Affiliation(s)
- Pik Kwan Lo
- Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Man Shing Wong
- Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, P.R. China.
| |
Collapse
|
40
|
Shanblatt SH, Revzin A. Two catabolite activator protein molecules bind to the galactose promoter region of Escherichia coli in the presence of RNA polymerase. Proc Natl Acad Sci U S A 1983; 80:1594-8. [PMID: 6300859 PMCID: PMC393648 DOI: 10.1073/pnas.80.6.1594] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The catabolite activator protein (CAP) of Escherichia coli, complexed with cAMP, is required for efficient initiation of transcription from the galactose P1 promoter (start site at +1) but not from the overlapping P2 promoter (start site at -5) [Musso, R. E., DiLauro, R., Adhya, S. & deCrombrugghe, B. (1977) Cell 12, 847-854]. We investigated the interactions between CAP/cAMP and the gal promoter region in the presence of RNA polymerase. DNase I protection experiments of gal promoter restriction fragments revealed that CAP/cAMP protects the DNA from digestion between positions -50 and -25 and that RNA polymerase protects it from -35 to +10; however, gal DNA in the presence of both CAP/cAMP and RNA polymerase is protected from DNase I digestion between positions -68 and +15. Results of exonuclease III protection experiments show that RNA polymerase alone protects the gal DNA from -30 to +15; when both CAP/cAMP and RNA polymerase are present in the reaction, protection is afforded from -65 to +20. We directly quantified the amount of cAMP and CAP bound to gal promoter DNA in the presence of RNA polymerase by selectively pelleting the ternary complexes (CAP/cAMP-RNA polymerase-gal promoter DNA) in a Beckman Airfuge. We found two CAP molecules specifically bound to the gal promoter, although only one cAMP molecule was found in the complex at low cAMP concentrations (but sufficient to support P1 transcription). Thus, both the DNA protection experiments and the centrifugation results indicate that RNA polymerase induces the binding of a second CAP molecule to the gal promoter in forming stable initiation complexes. It appears that the second CAP molecule is needed to stimulate initiation from the P1 promoter; this may be involved in regulating the relative rates at which transcription begins from the two gal start sites.
Collapse
|