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Chandrappa M, Swathi K, Girish Kumar S, Pullela PK. Nanomaterial assisted bulk scale synthesis of 2-methyl-6-nitroquinoline. Mater Today Proc 2020; 37:1469-1474. [PMID: 32837922 PMCID: PMC7415172 DOI: 10.1016/j.matpr.2020.07.103] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 07/05/2020] [Indexed: 06/11/2023]
Abstract
Quinolines are an interesting class of moieties with various medicinal chemistry uses. The most prominent is their ability to be used as the last line of therapy for bacterial and viral infections including recent COVID-19. The synthesis of quinoline is through a cyclization reaction and overall reaction yields are about 20%. The bulky ring and the associated crowding of functional groups limit the catalyst options. In this publication, the use of Fe3O4@SiO2 for enhancing yield improvements, especially for heterocyclics is reported. The use of the 40 nm sized silica functionalized magnetite nanoparticles seems to help in both condensation and cyclization steps of representative 2-methyl-6-nitroquinoline. Reaction time reduction due to surface enabled catalysis of nanoparticles is 110 min to 80 min. The reaction yield has doubled due to the presence of catalyst and the mechanism suggests this drastic result is due to stabilization of unstable intermediate on the acidic surface of the silica coating. This near homogeneous catalysis of 40 nm sized, silica functionalized, magnetite nanoparticles have far reaching applications in bulk drug industry for drugs like chloroquine & hydroxychloroquine, the two essential drugs for prophylactic use for COVID-1.
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Affiliation(s)
- M Chandrappa
- Department of Chemistry, CMR Institute of Technology, Bengaluru 560037, India
- Department of Chemistry, School of Engineering and Technology, Bengaluru 560043, India
| | - Korrapati Swathi
- Kallam Haranadha Reddy Institute of Technology, NH-5, Chowdavaram, Guntur 522019, India
| | - S Girish Kumar
- Department of Chemistry, School of Engineering and Technology, Bengaluru 560043, India
| | - Phani Kumar Pullela
- Department of Chemistry, CMR Institute of Technology, Bengaluru 560037, India
- Department of Chemistry, School of Engineering and Technology, Bengaluru 560043, India
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Sankari M, Rao PR, Hemachandran H, Pullela PK, Doss C GP, Tayubi IA, Subramanian B, Gothandam KM, Singh P, Ramamoorthy S. Prospects and progress in the production of valuable carotenoids: Insights from metabolic engineering, synthetic biology, and computational approaches. J Biotechnol 2018; 266:89-101. [DOI: 10.1016/j.jbiotec.2017.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 11/09/2017] [Accepted: 12/10/2017] [Indexed: 02/01/2023]
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Korrapati S, Muneppa C, Pullela PK, Shivashankar GK, Vijayalakshmi U. Objective measurement of isoniazid levels: practical approach for monitoring tuberculosis drug treatment adherence. IET Nanobiotechnol 2017. [DOI: 10.1049/iet-nbt.2016.0145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Swathi Korrapati
- Bigtec Pvt Ltd.59th ‘C’ cross, 4th ‘M’ Block, RajajinagarBengaluruKarnataka 560010India
- School of Advanced SciencesVIT UniversityVelloreTamil Nadu 632014India
| | - Chandrappa Muneppa
- Bigtec Pvt Ltd.59th ‘C’ cross, 4th ‘M’ Block, RajajinagarBengaluruKarnataka 560010India
- Department of ChemistrySchool of Engineering and TechnologyCMR UniversityBagaluruBengaluruKarnataka 562149India
| | - Phani Kumar Pullela
- Bigtec Pvt Ltd.59th ‘C’ cross, 4th ‘M’ Block, RajajinagarBengaluruKarnataka 560010India
- School of Advanced SciencesVIT UniversityVelloreTamil Nadu 632014India
- Department of ChemistrySchool of Engineering and TechnologyCMR UniversityBagaluruBengaluruKarnataka 562149India
- CMR Institute of TechnologyITPL Main RoadBengaluruKarnataka 560037India
| | - Girish Kumar Shivashankar
- Department of ChemistrySchool of Engineering and TechnologyCMR UniversityBagaluruBengaluruKarnataka 562149India
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Korrapati S, Pullela PK, Vijayalakshmi U. SPA enhanced FPIA‐based detection of pesticide residue with ppb/ppt level detection limit. IET Nanobiotechnol 2016; 11:24-31. [DOI: 10.1049/iet-nbt.2016.0031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Swathi Korrapati
- Bigtec Pvt. Ltd.59th ‘C’ cross, 4th ‘M’ Block, RajajinagarBangalore 560 010India
| | - Phani Kumar Pullela
- Department of Chemistry CMR Institute of TechnologyITPL Main RoadBangalore 560 037KarnatakaIndia
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Nair CB, Manjula J, Subramani PA, Nagendrappa PB, Manoj MN, Malpani S, Pullela PK, Subbarao PV, Ramamoorthy S, Ghosh SK. Differential Diagnosis of Malaria on Truelab Uno®, a Portable, Real-Time, MicroPCR Device for Point-Of-Care Applications. PLoS One 2016; 11:e0146961. [PMID: 26784111 PMCID: PMC4718663 DOI: 10.1371/journal.pone.0146961] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 12/23/2015] [Indexed: 11/27/2022] Open
Abstract
Background Sensitive and specific detection of malarial parasites is crucial in controlling the significant malaria burden in the developing world. Also important is being able to identify life threatening Plasmodium falciparum malaria quickly and accurately to reduce malaria related mortality. Existing methods such as microscopy and rapid diagnostic tests (RDTs) have major shortcomings. Here, we describe a new real-time PCR-based diagnostic test device at point-of-care service for resource-limited settings. Methods Truenat® Malaria, a chip-based microPCR test, was developed by bigtec Labs, Bangalore, India, for differential identification of Plasmodium falciparum and Plasmodium vivax parasites. The Truenat Malaria tests runs on bigtec’s Truelab Uno® microPCR device, a handheld, battery operated, and easy-to-use real-time microPCR device. The performance of Truenat® Malaria was evaluated versus the WHO nested PCR protocol. The Truenat® Malaria was further evaluated in a triple-blinded study design using a sample panel of 281 specimens created from the clinical samples characterized by expert microscopy and a rapid diagnostic test kit by the National Institute of Malaria Research (NIMR). A comparative evaluation was done on the Truelab Uno® and a commercial real-time PCR system. Results The limit of detection of the Truenat Malaria assay was found to be <5 parasites/μl for both P. falciparum and P. vivax. The Truenat® Malaria test was found to have sensitivity and specificity of 100% each, compared to the WHO nested PCR protocol based on the evaluation of 100 samples. The sensitivity using expert microscopy as the reference standard was determined to be around 99.3% (95% CI: 95.5–99.9) at the species level. Mixed infections were identified more accurately by Truenat Malaria (32 samples identified as mixed) versus expert microscopy and RDTs which detected 4 and 5 mixed samples, respectively. Conclusion The Truenat® Malaria microPCR test is a valuable diagnostic tool and implementation should be considered not only for malaria diagnosis but also for active surveillance and epidemiological intervention.
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Affiliation(s)
- Chandrasekhar Bhaskaran Nair
- bigtec Private Limited, 2nd Floor, Golden Heights, 59th C Cross, 4th M Block, Rajajinagar, Bangalore, 560 010, Karnataka, India
- School of Bio Sciences and Technology, School of Advanced Sciences VIT University, Vellore, Tamil Nadu, 632014, India
| | - Jagannath Manjula
- bigtec Private Limited, 2nd Floor, Golden Heights, 59th C Cross, 4th M Block, Rajajinagar, Bangalore, 560 010, Karnataka, India
| | - Pradeep Annamalai Subramani
- National Institute of Malaria Research, ICMR Complex, Poojanahalli, Kannamangala Post, Devanahalli, Bangalore, 562 110, Karnataka, India
| | - Prakash B. Nagendrappa
- Institute of Trans-disciplinary Health Sciences and Technology (IHST), FRLHT, 74/2, Jarakabande Kaval, Attur post, Via Yelahanka, Bangalore, 560 106, Karnataka, India
| | - Mulakkapurath Narayanan Manoj
- bigtec Private Limited, 2nd Floor, Golden Heights, 59th C Cross, 4th M Block, Rajajinagar, Bangalore, 560 010, Karnataka, India
| | - Sukriti Malpani
- bigtec Private Limited, 2nd Floor, Golden Heights, 59th C Cross, 4th M Block, Rajajinagar, Bangalore, 560 010, Karnataka, India
| | - Phani Kumar Pullela
- bigtec Private Limited, 2nd Floor, Golden Heights, 59th C Cross, 4th M Block, Rajajinagar, Bangalore, 560 010, Karnataka, India
| | - Pillarisetti Venkata Subbarao
- bigtec Private Limited, 2nd Floor, Golden Heights, 59th C Cross, 4th M Block, Rajajinagar, Bangalore, 560 010, Karnataka, India
| | - Siva Ramamoorthy
- School of Bio Sciences and Technology, School of Advanced Sciences VIT University, Vellore, Tamil Nadu, 632014, India
| | - Susanta K. Ghosh
- National Institute of Malaria Research, ICMR Complex, Poojanahalli, Kannamangala Post, Devanahalli, Bangalore, 562 110, Karnataka, India
- * E-mail:
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Sanjeeva SK, Korrapati S, Nair CB, Rao PVS, Pullela PK, Vijayalakshmi U, Siva R. Hydrophobic interactions in donor-disulphide-acceptor (DSSA) probes looking beyond fluorescence resonance energy transfer theory. J Fluoresc 2014; 24:1297-306. [PMID: 24912449 DOI: 10.1007/s10895-014-1414-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 05/27/2014] [Indexed: 11/30/2022]
Abstract
Donor-linker-acceptor (DSSA) is a concept in fluorescence chemistry with acceptor being a fluorescent compound (FRET) or quencher. The DSSA probes used to measure thiol levels in vitro and in vivo. The reduction potential of these dyes are in the range of -0.60 V, much lower than the best thiol reductant reported in literature, the DTT (-0.33 V). DSSA disulphide having an unusually low reduction potential compared to the typical thiol reductants is a puzzle. Secondly, DSSA probes have a cyclized rhodamine ring as acceptor which does not have any spectral overlap with fluorescein, but quenches its absorbance and fluorescence. To understand the structural features of DSSA probes, we have synthesized DSSANa and DSSAOr. The calculated reduction potential of these dyes suggest that DSSA probes have an alternate mechanism from the FRET based quenching, namely hydrophobic interaction or dye to dye quenching. The standard reduction potential change with increasing complexity and steric hindrance of the molecule is small, suggesting that ultra- low Eo' has no contribution from the disulphide linker and is based on structural interactions between fluorescein and cyclized rhodamine. Our results help to understand the DSSA probe quenching mechanism and provide ways to design fluorescent probes.
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McCullough C, Pullela PK, Im SC, Waskell L, Sem D. The synthesis, characterization, and application of ¹³C-methyl isocyanide as an NMR probe of heme protein active sites. Methods Mol Biol 2013; 987:51-59. [PMID: 23475666 PMCID: PMC4057429 DOI: 10.1007/978-1-62703-321-3_4] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The cytochromes P450 (CYPs) play a central role in a variety of important biological oxidations, such as steroid synthesis and the metabolism of xenobiotic compounds, including most drugs. Because CYPs are frequently assayed as drug targets or as anti-targets, tools that provide confirmation of active-site binding and information on binding orientation would be of great utility. Of greatest value are assays that are reasonably high throughput. Other heme proteins, too-such as the nitric oxide synthases (NOSs), with their importance in signaling, regulation of blood pressure, and involvement in the immune response-often display critical roles in the complex functions of many higher organisms, and also require improved assay methods. To this end, we have developed an analog of cyanide, with a (13)CH3-reporter group attached to make methyl isocyanide. We describe the synthesis and use of (13)C-methyl isocyanide as a probe of both bacterial (P450cam) and membrane-bound mammalian (CYP2B4) CYPs. The (13)C-methyl isocyanide probe can be used in a relatively high-throughput 1-D experiment to identify binders, but it can also be used to detect structural changes in the active site based on chemical shift changes, and potentially nuclear Overhauser effects between probe and inhibitor.
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Jonhera T, Pullela PK, Bassam WT, Carvan MJ, Sem DS. Dabcyl/Fluorescein‐based Probes for Detection of Thiols and Disulfides: Proteomic Application to Discovery of Reactive Disulfides in Live Cells. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.525.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Timothy Jonhera
- Chemical Proteomics Facility at MarquetteDepartment of ChemistryMarquette UniversityMilwaukeeWI
| | | | | | | | - Daniel S Sem
- Chemical Proteomics Facility at MarquetteDepartment of ChemistryMarquette UniversityMilwaukeeWI
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McCullough CR, Pullela PK, Im SC, Waskell L, Sem DS. 13C-Methyl isocyanide as an NMR probe for cytochrome P450 active sites. J Biomol NMR 2009; 43:171-178. [PMID: 19199046 PMCID: PMC3870883 DOI: 10.1007/s10858-009-9300-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 01/08/2009] [Indexed: 05/27/2023]
Abstract
The cytochromes P450 (CYPs) play a central role in many biologically important oxidation reactions, including the metabolism of drugs and other xenobiotic compounds. Because they are often assayed as both drug targets and anti-targets, any tools that provide: (a) confirmation of active site binding and (b) structural data, would be of great utility, especially if data could be obtained in reasonably high throughput. To this end, we have developed an analog of the promiscuous heme ligand, cyanide, with a (13)CH(3)-reporter attached. This (13)C-methyl isocyanide ligand binds to bacterial (P450cam) and membrane-bound mammalian (CYP2B4) CYPs. It can be used in a rapid 1D experiment to identify binders, and provides a qualitative measure of structural changes in the active site.
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Affiliation(s)
- Christopher R McCullough
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA
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Yao H, McCullough CR, Costache AD, Pullela PK, Sem DS. Structural evidence for a functionally relevant second camphor binding site in P450cam: model for substrate entry into a P450 active site. Proteins 2007; 69:125-38. [PMID: 17598143 DOI: 10.1002/prot.21508] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
P450cam has long served as a prototype for the cytochrome P450 (CYP) gene family. But, little is known about how substrate enters its active site pocket, and how access is achieved in a way that minimizes exposure of the reactive heme. We hypothesize that P450cam may first bind substrate transiently near the mobile F-G helix that covers the active site pocket. Such a two-step binding process is kinetically required if P450cam rarely populates an open conformation-as suggested by previous literature and the inability to obtain a crystal structure of P450cam in an open conformation. Such a mechanism would minimize exposure of the heme by allowing P450cam to stay in a closed conformation as long as possible, since only brief flexing into an open conformation would be required to allow substrate entry. To test this model, we have attempted to dock a second camphor molecule into the crystal structure of camphor-bound P450cam. The docking identified only one potential entry site pocket, a well-defined cavity on the F-helix side of the F-G flap, 16 A from the heme iron. Location of this entry site pocket is consistent with our NMR T1 relaxation-based measurements of distances for a camphor that binds in fast exchange (active site camphor is known to bind in slow exchange). Presence of a second camphor binding site is also confirmed with [(1)H-(13)C] HSQC titrations of (13)CH3-threonine labeled P450cam. To confirm that camphor can bind outside of the active site pocket, (13)CH3-S-pyridine was bound to the heme iron to physically block the active site, and to serve as an NMR chemical shift probe. Titration of this P450cam-pyridine complex confirms that camphor can bind to a site outside the active site pocket, with an estimated Kd of 43 microM. The two-site binding model that is proposed based on these data is analogous to that recently proposed for CYP3A4, and is consistent with recent crystal structures of P450cam bound to tethered-substrates, which force a partially opened conformation.
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Affiliation(s)
- Huili Yao
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, USA
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Chiku T, Pullela PK, Sem DS. Thiol reactive dyes as probes for kinase assays. FASEB J 2007. [DOI: 10.1096/fasebj.21.5.a263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Taurai Chiku
- Department of ChemistryMarquette UniversityMilwaukeeWI53233
| | | | - Daniel S. Sem
- Department of ChemistryMarquette UniversityMilwaukeeWI53233
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Abstract
Kinases and ATPases produce adenosine diphosphate (ADP) as a common product, so an assay that detects ADP would provide a universal means for activity-based screening of enzymes in these families. Because it is known that most kinases accept ATPbetaS (sulfur on the beta-phosphorous) as a substrate in place of adenosine triphosphate (ATP), the authors have developed a continuous assay using this substrate, with detection of the ADPbetaS product using dithio reagents. Such an assay is possible because dithio groups react selectively with ADPbetaS and not with ATPbetaS. Thiol detection was done using both Ellman's reagent (DTNB) and a recently developed fluorescent dithio reagent, DSSA. Therefore, the assay can be run in both absorbance and fluorescence detection modes. The assay was used to perform steady-state kinetic analyses of both hexokinase and myosin ATPase. It was also used to demonstrate the diastereoselectivity of hexokinase (R) and myosin ATPase (S) for the isomers of ATPbetaS, consistent with previous results. When run in fluorescence mode using a plate reader, an average Z' value of 0.54 was obtained, suggesting the assay is appropriate for high-throughput screening.
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Affiliation(s)
- Taurai Chiku
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, Milwaukee, WI 53201-1881, USA
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McCullough CR, Pullela PK, Sem DS. An NMR‐Based Binding Assay Used To Screen For Compounds That Bind To Cytochrome P450 Enzymes. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a939-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Daniel S. Sem
- CPFMMarquette University535 N. 14th St.MilwaukeeWI53233
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Pullela PK, Alby K, Varela H, Sem DS. Effect of thiol reductants on estrogen and estrogen receptor: revisiting previous assays. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kevin Alby
- CPFMMarquette University535 N.14th streetMilwaukeeWI53233
| | - Hector Varela
- CPFMMarquette University535 N.14th streetMilwaukeeWI53233
| | - Daniel S Sem
- CPFMMarquette University535 N.14th streetMilwaukeeWI53233
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Pullela PK, Chiku T, Carvan MJ, Sem DS. Fluorescent probes for in vivo redox potential measurement and thiol rich protein function. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a74-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Taurai Chiku
- CPFMMarquette University535 N.14th streetMilwaukeeWI53233
| | - Michael J Carvan
- Marine & Freshwater Biomedical Sciences Center600 E. Greenfield Ave.MilwaukeeWI53204
| | - Daniel S Sem
- Marine & Freshwater Biomedical Sciences Center600 E. Greenfield Ave.MilwaukeeWI53204
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Pullela PK, Chiku T, Carvan MJ, Sem DS. Fluorescence-based detection of thiols in vitro and in vivo using dithiol probes. Anal Biochem 2006; 352:265-73. [PMID: 16527239 DOI: 10.1016/j.ab.2006.01.047] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 01/24/2006] [Accepted: 01/27/2006] [Indexed: 10/25/2022]
Abstract
Thiols play a central role in maintaining biological homeostasis. Their levels can change dramatically in response to oxidative stress associated with toxic insults, bacterial infection, and disease. Therefore, a reagent that can monitor thiol levels both in vitro and in vivo would be useful for assays and as a biomarker. Such a reagent should (i) be selective for thiols, (ii) be able to penetrate cell walls, and (iii) have a low reduction potential so as not to create oxidative stress in a cell. We have developed such a fluorescent reagent (DSSA) based on a dithiol linker: (i) the use of a dithiol linker makes it selective for thiols; (ii) the use of fluorophores that populate neutral states at physiological pH improves cell wall penetration; and (iii) because of the reagent's low reduction potential (-0.60 V), it will not stress cells oxidatively. For example, 5 microM of reagent is responsive to changes in glutathione levels in the physiologically relevant range of 1 to 10mM, yet this would oxidize less than 1% of cellular glutathione. In Escherichia coli, decreased thiol levels were detected in cells deficient in glutathione synthesis. In zebrafish embryos, the DSSA reagent permitted detection of unusually high thiol levels in the zebrafish chorion.
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Affiliation(s)
- Phani Kumar Pullela
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, Milwaukee, WI 53201, USA
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Costache AD, Pullela PK, Kasha P, Tomasiewicz H, Sem DS. Homology-modeled ligand-binding domains of zebrafish estrogen receptors alpha, beta1, and beta2: from in silico to in vivo studies of estrogen interactions in Danio rerio as a model system. Mol Endocrinol 2005; 19:2979-90. [PMID: 16081519 DOI: 10.1210/me.2004-0435] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Homology models were constructed for the ligand-binding domains of zebrafish estrogen receptors (zfERs) alpha, beta(1), and beta(2). Estradiol-binding sites are nearly identical in zfERs and their human homologs, suggesting that zebrafish will serve as a good model system for studying human ER-binding drugs. Conversely, studies of endocrine disruptor effects on zebrafish will benefit from the wealth of data available on xenoestrogen interactions with human ERs. Compounds flagged by the Interagency Coordinating Committee on the Validation of Alternative Methods for endocrine disruptor screening were docked into our zfER homology models. Ideally, these in silico docking studies would be complemented with in vivo binding studies. To this end, fluorescently tagged estradiol was docked into zfERalpha and found to bind in the same manner as in human ERalpha, with fluorescein preferentially occupying a region between helices 11 and 12. Fluorescently tagged estradiol was synthesized and was found to localize along the path of primordial germ cell migration in the developing zebrafish embryo 3 d after fertilization, consistent with previous reports of 1) a role for estradiol in sex determination, and 2) the first appearance of ERs 2 d after fertilization. These data provide a foundation for future in silico and in vivo binding studies of estrogen agonists and antagonists with zebrafish ERs.
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Affiliation(s)
- Aurora D Costache
- Chemical Proteomics Facility at Marquette, Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201, USA
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