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Keshari K, Santra A, Velasco L, Sauvan M, Kaur S, Ugale AD, Munshi S, Marco JF, Moonshiram D, Paria S. Functional Model of Compound II of Cytochrome P450: Spectroscopic Characterization and Reactivity Studies of a Fe IV-OH Complex. JACS Au 2024; 4:1142-1154. [PMID: 38559734 PMCID: PMC10976569 DOI: 10.1021/jacsau.3c00844] [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] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/12/2024] [Accepted: 02/26/2024] [Indexed: 04/04/2024]
Abstract
Herein, we show that the reaction of a mononuclear FeIII(OH) complex (1) with N-tosyliminobenzyliodinane (PhINTs) resulted in the formation of a FeIV(OH) species (3). The obtained complex 3 was characterized by an array of spectroscopic techniques and represented a rare example of a synthetic FeIV(OH) complex. The reaction of 1 with the one-electron oxidizing agent was reported to form a ligand-oxidized FeIII(OH) complex (2). 3 revealed a one-electron reduction potential of -0.22 V vs Fc+/Fc at -15 °C, which was 150 mV anodically shifted than 2 (Ered = -0.37 V vs Fc+/Fc at -15 °C), inferring 3 to be more oxidizing than 2. 3 reacted spontaneously with (4-OMe-C6H4)3C• to form (4-OMe-C6H4)3C(OH) through rebound of the OH group and displayed significantly faster reactivity than 2. Further, activation of the hydrocarbon C-H and the phenolic O-H bond by 2 and 3 was compared and showed that 3 is a stronger oxidant than 2. A detailed kinetic study established the occurrence of a concerted proton-electron transfer/hydrogen atom transfer reaction of 3. Studying one-electron reduction of 2 and 3 using decamethylferrocene (Fc*) revealed a higher ket of 3 than 2. The study established that the primary coordination sphere around Fe and the redox state of the metal center is very crucial in controlling the reactivity of high-valent Fe-OH complexes. Further, a FeIII(OMe) complex (4) was synthesized and thoroughly characterized, including X-ray structure determination. The reaction of 4 with PhINTs resulted in the formation of a FeIV(OMe) species (5), revealing the presence of two FeIV species with isomer shifts of -0.11 mm/s and = 0.17 mm/s in the Mössbauer spectrum and showed FeIV/FeIII potential at -0.36 V vs Fc+/Fc couple in acetonitrile at -15 °C. The reactivity studies of 5 were investigated and compared with the FeIV(OH) complex (3).
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Affiliation(s)
- Kritika Keshari
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
| | - Aakash Santra
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
| | - Lucía Velasco
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Maxime Sauvan
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Simarjeet Kaur
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
| | - Ashok D. Ugale
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sandip Munshi
- School
of Chemical Science, Indian Association
for the Cultivation of Science, Raja S C Mulliick Road, Kolkata 700032, India
| | - J. F. Marco
- Instituto
de Quimica Fisica Blas Cabrera, Consejo
Superior de Investigaciones Científicas, C. de Serrano, 119, Serrano, Madrid 28006, Spain
| | - Dooshaye Moonshiram
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sayantan Paria
- Department
of Chemistry, Indian Institute of Technology
Delhi, Hauz Khas, New Delhi 110016, India
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Ravel-Massol R, Munshi S, Pujol A, Garcia-Serres R, Saffon-Merceron N, Mézailles N, Fustier-Boutignon M. One Ligand to Bind them All: S~C~S 2- Carbon- and Sulfur-Based Gem-Dianion as Structuring Ligand for Iron Polymetallic Assemblies. Chemistry 2023; 29:e202302130. [PMID: 37681691 DOI: 10.1002/chem.202302130] [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] [Received: 07/13/2023] [Indexed: 09/09/2023]
Abstract
Numerous synthetic models of the FeMo-co cluster of nitrogenases have been proposed to find the simplest structure with relevant reactivity. Indeed, such structures are able to perform multi-electrons reduction processes, such as the conversion of N2 to ammonia, and of CO2 into methane and alkenes. The most challenging parameter to imitate is indeed the central carbide ligand, which is believed to maintain the integrity of iron sulfide assembly during the course of catalytic cycles. The study proposes the use of bis(diphenylthiophosphinoyl)methanediide (SCS)2- as an ideal platform for the synthesis of bi- and tetra-metallic iron complexes, in which the iron-carbon interaction is maintained upon structural diversification and redox state changes.
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Affiliation(s)
- Raphaël Ravel-Massol
- Laboratoire Hétérochimie Fondamentale et Appliquée, LHFA UMR CNRS 5069, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Sandip Munshi
- Laboratoire Hétérochimie Fondamentale et Appliquée, LHFA UMR CNRS 5069, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Anthony Pujol
- Laboratoire Hétérochimie Fondamentale et Appliquée, LHFA UMR CNRS 5069, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Ricardo Garcia-Serres
- Université Grenoble Alpes, CNRS, CEA, IRIG Laboratoire de Chimie et Biologie des Métaux, 17 rue des Martyrs, 38000, Grenoble, France
| | - Nathalie Saffon-Merceron
- Institut de Chimie de Toulouse ICT-UAR2599, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Nicolas Mézailles
- Laboratoire Hétérochimie Fondamentale et Appliquée, LHFA UMR CNRS 5069, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
| | - Marie Fustier-Boutignon
- Laboratoire Hétérochimie Fondamentale et Appliquée, LHFA UMR CNRS 5069, Université Paul Sabatier, CNRS, 118 Route de Narbonne, 31062, Toulouse, France
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3
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Kaur S, Bera M, Santra A, Munshi S, Sterbinsky GE, Wu T, Moonshiram D, Paria S. Effect of Redox-Inactive Metal Ion-Nickel(III) Interactions on the Redox Properties and Proton-Coupled Electron Transfer Reactivity. Inorg Chem 2022; 61:14252-14266. [PMID: 36041064 DOI: 10.1021/acs.inorgchem.2c01472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mononuclear nickel(II) and nickel(III) complexes of a bisamidate-bisalkoxide ligand, (NMe4)2[NiII(HMPAB)] (1) and (NMe4)[NiIII(HMPAB)] (2), respectively, have been synthesized and characterized by various spectroscopic techniques including X-ray crystallography. The reaction of redox-inactive metal ions (Mn+ = Ca2+, Mg2+, Zn2+, Y3+, and Sc3+) with 2 resulted in 2-Mn+ adducts, which was assessed by an array of spectroscopic techniques including X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and reactivity studies. The X-ray structure of Ca2+ coordinated to Ni(III) complexes, 2-Ca2+T, was determined and exhibited an average Ni-Ca distance of 3.1253 Å, close to the metal ions' covalent radius. XAS analysis of 2-Ca2+ and 2-Y3+ in solution further revealed an additional coordination to Ca and Y in the 2-Mn+ adducts with shortened Ni-M distances of 2.15 and 2.11 Å, respectively, implying direct bonding interactions between Ni and Lewis acids (LAs). Such a short interatomic distance between Ni(III) and M is unprecedented and was not observed before. EPR analysis of 2 and 2-Mn+ species, moreover, displayed rhombic signals with gav > 2.12 for all complexes, supporting the +III oxidation state of Ni. The NiIII/NiII redox potential of 2 and 2-Mn+ species was determined, and a plot of E1/2 of 2-Mn+ versus pKa of [M(H2O)n]m+ exhibited a linear relationship, implying that the NiIII/NiII potential of 2 can be tuned with different redox-inactive metal ions. Reactivity studies of 2 and 2-Mn+ with different 4-X-2,6-ditert-butylphenol (4-X-DTBP) and other phenol derivatives were performed, and based on kinetic studies, we propose the involvement of a proton-coupled electron transfer (PCET) pathway. Analysis of the reaction products after the reaction of 2 with 4-OMe-DTBP showed the formation of a Ni(II) complex (1a) where one of the alkoxide arms of the ligand is protonated. A pKa value of 24.2 was estimated for 1a. The reaction of 2-Mn+ species was examined with 4-OMe-DTBP, and it was observed that the k2 values of 2-Mn+ species increase by increasing the Lewis acidity of redox-inactive metal ions. However, the obtained k2 values for 2-Mn+ species are much lower compared to the k2 value for 2. Such a variation of PCET reactivity between 2 and 2-Mn+ species may be attributed to the interactions between Ni(III) and LAs. Our findings show the significance of the secondary coordination sphere effect on the PCET reactivity of Ni(III) complexes and furnish important insights into the reaction mechanism involving high-valent nickel species, which are frequently invoked as key intermediates in Ni-mediated enzymatic reactions, solar-fuel catalysis, and biomimetic/synthetic transformation reactions.
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Affiliation(s)
- Simarjeet Kaur
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Moumita Bera
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Aakash Santra
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - George E Sterbinsky
- X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Tianpin Wu
- X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Dooshaye Moonshiram
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Sor Juana Inés de la Cruz, 3, Madrid 28049, Spain
| | - Sayantan Paria
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Moore D, Munshi S. P.191 Cerebral venous thrombosis in pregnancy after spinal and epidural blood patch dural puncture. Int J Obstet Anesth 2022. [DOI: 10.1016/j.ijoa.2022.103487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Munshi S, Sinha A, Yiga S, Banerjee S, Singh R, Hossain MK, Haukka M, Valiati AF, Huelsmann RD, Martendal E, Peralta R, Xavier F, Wendt OF, Paine TK, Nordlander E. Hydrogen-atom and oxygen-atom transfer reactivities of iron(IV)-oxo complexes of quinoline-substituted pentadentate ligands. Dalton Trans 2022; 51:870-884. [PMID: 34994361 DOI: 10.1039/d1dt03381f] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A series of iron(II) complexes with the general formula [FeII(L2-Qn)(L)]n+ (n = 1, L = F-, Cl-; n = 2, L = NCMe, H2O) have been isolated and characterized. The X-ray crystallographic data reveals that metal-ligand bond distances vary with varying ligand field strengths of the sixth ligand. While the complexes with fluoride, chloride and water as axial ligand are high spin, the acetonitrile-coordinated complex is in a mixed spin state. The steric bulk of the quinoline moieties forces the axial ligands to deviate from the Fe-Naxial axis. A higher deviation/tilt is noted for the high spin complexes, while the acetonitrile coordinated complex displays least deviation. This deviation from linearity is slightly less in the analogous low-spin iron(II) complex [FeII(L1-Qn)(NCMe)]2+ of the related asymmetric ligand L1-Qn due to the presence of only one sterically demanding quinoline moiety. The two iron(II)-acetonitrile complexes [FeII(L2-Qn)(NCMe)]2+ and [FeII(L1-Qn)(NCMe)]2+ generate the corresponding iron(IV)-oxo species with higher thermal stability of the species supported by the L1-Qn ligand. The crystallographic and spectroscopic data for [FeIV(O)(L1-Qn)](ClO4)2 bear resemblance to other crystallographically characterized S = 1 iron(IV)-oxo complexes. The hydrogen atom transfer (HAT) and oxygen atom transfer (OAT) reactivities of both the iron(IV)-oxo complexes were investigated, and a Box-Behnken multivariate optimization of the parameters for catalytic oxidation of cyclohexane by [FeII(L2-Qn)(NCMe)]2+ using hydrogen peroxide as the terminal oxidant is presented. An increase in the average Fe-N bond length in [FeII(L1-Qn)(NCMe)]2+ is also manifested in higher HAT and OAT rates relative to the other reported complexes of ligands based on the N4Py framework. The results reported here confirm that the steric influence of the ligand environment is of critical importance for the reactivity of iron(IV)-oxo complexes, but additional electronic factors must influence the reactivity of iron-oxo complexes of N4Py derivatives.
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Affiliation(s)
- Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, India.
| | - Arup Sinha
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden. .,Department of Chemistry, School of Advanced Science, Vellore Institute of Technology, Vellore, India
| | - Solomon Yiga
- Center for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden. .,Department of Chemistry, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Sridhar Banerjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, India.
| | - Reena Singh
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
| | - Md Kamal Hossain
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
| | - Matti Haukka
- Department of Chemistry, University of Jyväskylä, Box 35, FI-400 14, Jyväskylä, Finland
| | - Andrei Felipe Valiati
- Department of Chemistry, LABINC, Universidade Federal de Santa Catarina (UFSC), 88040-900 Florianopolis, Santa Catarina, Brazil
| | - Ricardo Dagnoni Huelsmann
- Department of Chemistry, Center for Technological Sciences, Universidade do Estado de Santa Catarina (UDESC), 89219-710 Joinville, Santa Catarina, Brazil
| | - Edmar Martendal
- Department of Chemistry, Center for Technological Sciences, Universidade do Estado de Santa Catarina (UDESC), 89219-710 Joinville, Santa Catarina, Brazil
| | - Rosely Peralta
- Department of Chemistry, LABINC, Universidade Federal de Santa Catarina (UFSC), 88040-900 Florianopolis, Santa Catarina, Brazil
| | - Fernando Xavier
- Department of Chemistry, Center for Technological Sciences, Universidade do Estado de Santa Catarina (UDESC), 89219-710 Joinville, Santa Catarina, Brazil
| | - Ola F Wendt
- Center for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
| | - Tapan K Paine
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Kolkata, India.
| | - Ebbe Nordlander
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00 Lund, Sweden.
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Roach M, Munshi S. P.150 SARS-CoV-2 causing septic shock in pregnancy. Int J Obstet Anesth 2021. [PMCID: PMC8186984 DOI: 10.1016/j.ijoa.2021.103148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Man R, Munshi S. P.86 Feedback of major obstetric haemorrhage simulation training. Int J Obstet Anesth 2021. [DOI: 10.1016/j.ijoa.2021.103084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sarkar S, Sarkar P, Munshi S, Ghosh P. One-Pot Dual C-C Coupling Reaction via Site Selective Cascade Formation by Pd II -Cryptate of an Amino-Ether Heteroditopic Macrobicycle. Chemistry 2021; 27:7307-7314. [PMID: 33439499 DOI: 10.1002/chem.202005397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 12/18/2020] [Indexed: 12/24/2022]
Abstract
Selectivity of aryl iodo over ethynyl iodo toward the Suzuki cross coupling reaction is explored by utilizing a palladium complex of amino-ether heteroditopic macrobicycle. Subsequently, unreacted ethynyl iodide undergoes homocoupling reaction in the same catalytic atmosphere, thereby representing a cascade dual C-C coupling reaction. Furthermore, this approach is extended for novel one-pot synthesis of unsymmetrical 1,3-diynes.
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Affiliation(s)
- Sayan Sarkar
- School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, 700032, West Bengal, India
| | - Piyali Sarkar
- School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, 700032, West Bengal, India
| | - Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, 700032, West Bengal, India
| | - Pradyut Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science (IACS), 2A and 2B Raja S.C. Mullick Road, Jadavpur, Kolkata, 700032, West Bengal, India
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Munshi S, Jana RD, Paine TK. Oxidative degradation of toxic organic pollutants by water soluble nonheme iron(iv)-oxo complexes of polydentate nitrogen donor ligands. Dalton Trans 2021; 50:5590-5597. [PMID: 33908934 DOI: 10.1039/d0dt04421k] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability of four mononuclear nonheme iron(iv)-oxo complexes supported by polydentate nitrogen donor ligands to degrade organic pollutants has been investigated. The water soluble iron(ii) complexes upon treatment with ceric ammonium nitrate (CAN) in aqueous solution are converted into the corresponding iron(iv)-oxo complexes. The hydrogen atom transfer (HAT) ability of iron(iv)-oxo species has been exploited for the oxidation of halogenated phenols and other toxic pollutants with weak X-H (X = C, O, S, etc.) bonds. The iron-oxo oxidants can oxidize chloro- and fluorophenols with moderate to high yields under stoichiometric as well as catalytic conditions. Furthermore, these oxidants perform selective oxidative degradation of several persistent organic pollutants (POPs) such as bisphenol A, nonylphenol, 2,4-D (2,4-dichlorophenoxyacetic acid) and gammaxene. This work demonstrates the utility of water soluble iron(iv)-oxo complexes as potential catalysts for the oxidative degradation of a wide range of toxic pollutants, and these oxidants could be considered as an alternative to conventional oxidation methods.
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Affiliation(s)
- Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
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Keshari K, Bera M, Velasco L, Munshi S, Gupta G, Moonshiram D, Paria S. Characterization and reactivity study of non-heme high-valent iron-hydroxo complexes. Chem Sci 2021; 12:4418-4424. [PMID: 34163706 PMCID: PMC8179568 DOI: 10.1039/d0sc07054h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A terminal FeIIIOH complex, [FeIII(L)(OH)]2− (1), has been synthesized and structurally characterized (H4L = 1,2-bis(2-hydroxy-2-methylpropanamido)benzene). The oxidation reaction of 1 with one equiv. of tris(4-bromophenyl)ammoniumyl hexachloroantimonate (TBAH) or ceric ammonium nitrate (CAN) in acetonitrile at −45 °C results in the formation of a FeIIIOH ligand radical complex, [FeIII(L˙)(OH)]− (2), which is hereby characterized by UV-visible, 1H nuclear magnetic resonance, electron paramagnetic resonance, and X-ray absorption spectroscopy techniques. The reaction of 2 with a triphenylcarbon radical further gives triphenylmethanol and mimics the so-called oxygen rebound step of Cpd II of cytochrome P450. Furthermore, the reaction of 2 was explored with different 4-substituted-2,6-di-tert-butylphenols. Based on kinetic analysis, a hydrogen atom transfer (HAT) mechanism has been established. A pKa value of 19.3 and a BDFE value of 78.2 kcal/mol have been estimated for complex 2. One-electron oxidation of an FeIII–OH complex (1) results in the formation of a FeIII–OH ligand radical complex (2). Its reaction with (C6H5)3C˙ results in the formation of (C6H5)3COH, which is a functional mimic of compound II of cytochrome P450.![]()
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Affiliation(s)
- Kritika Keshari
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Moumita Bera
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Lucía Velasco
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia Calle Faraday, 9 28049 Madrid Spain
| | - Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata 700032 India
| | - Geetika Gupta
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Dooshaye Moonshiram
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia Calle Faraday, 9 28049 Madrid Spain
| | - Sayantan Paria
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
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Okoli C, Schwenk A, Radford M, Myland M, Taylor S, Darley A, Barnes J, Fox A, Grimson F, Reeves I, Munshi S, Croucher A, Boxall N, Benn P, Paice A, van Wyk J, Khoo S. Polypharmacy and potential drug-drug interactions for people with HIV in the UK from the Climate-HIV database. HIV Med 2020; 21:471-480. [PMID: 32671950 PMCID: PMC7497154 DOI: 10.1111/hiv.12879] [Citation(s) in RCA: 11] [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] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2020] [Indexed: 11/30/2022]
Abstract
Objectives People with HIV (PWHIV) are likely to need therapies for comorbidities as they age. We assessed risk of drug–drug interactions (DDIs) in PWHIV. Methods The Climate‐HIV electronic recording system was used to cross‐sectionally analyse records from PWHIV aged ≥ 18 years attending four UK HIV units with a current antiretroviral (ARV) prescription in February 2018. Antiretroviral and non‐ARV medications were categorized by clinical significance of DDIs (University of Liverpool DDI tool). Potential DDIs were predicted using treatment guidelines for commonly recorded comorbidities. Results Among 4630 PWHIV (44% female), 41% were ≥ 50 years old. The average number of non‐ARV comedications increased from < 1 for patients aged ≤ 24 years to > 5 for patients aged ≥ 75 years; 65% were taking one or more non‐ARV comedications. The median (interquartile range) number of non‐ARVs was 1 (0–2) and 2 (1–5) for those aged < 50 and ≥ 50 years, respectively. Common comorbidities/concurrent health conditions occurred more frequently in patients aged ≥ 50 years vs. < 50 (53% vs. 34%). Boosted protease inhibitors were associated with the highest proportion of contraindicated comedications; dolutegravir and raltegravir had the fewest. For non‐ARVs, sildenafil and quetiapine were most likely to result in DDIs. Guideline‐recommended treatments for hepatitis C, hepatitis B, and tuberculosis had the highest proportions of contraindications when combined with ARV regimens, while treatments for hepatitis C, malignancy, and mental health conditions had the highest proportion of combinations potentially causing DDIs requiring dose monitoring or adjustment. Conclusions Non‐ARV use by PWHIV is high and increases with age. Treatment decisions for ageing PWHIV should consider guideline recommendations for comorbidities.
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Affiliation(s)
- C Okoli
- ViiV Healthcare, Brentford, UK
| | - A Schwenk
- North Middlesex University Hospital NHS Trust, London, UK
| | | | - M Myland
- IQVIA Real World Insights, UK & Ireland, London, UK
| | - S Taylor
- Birmingham Heartlands HIV Service, Department of Infection and Immunology, Birmingham Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - A Darley
- Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - J Barnes
- Birmingham Heartlands HIV Service, Department of Infection and Immunology, Birmingham Heartlands Hospital, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - A Fox
- Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - F Grimson
- IQVIA Real World Insights, UK & Ireland, London, UK
| | - I Reeves
- Homerton University Hospital NHS Foundation Trust, London, UK
| | - S Munshi
- Homerton University Hospital NHS Foundation Trust, London, UK
| | - A Croucher
- Homerton University Hospital NHS Foundation Trust, London, UK
| | - N Boxall
- IQVIA Real World Insights, UK & Ireland, London, UK
| | - P Benn
- ViiV Healthcare, Brentford, UK
| | - A Paice
- ViiV Healthcare, Brentford, UK
| | | | - S Khoo
- University of Liverpool, Liverpool, UK
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Rahaman R, Munshi S, Banerjee S, Chakraborty B, Bhunia S, Paine TK. Dioxygen reactivity of iron( ii)–gentisate/1,4-dihydroxy-2-naphthoate complexes of N4 ligands: oxidative coupling of 1,4-dihydroxy-2-naphthoate. Dalton Trans 2019; 48:16993-17004. [DOI: 10.1039/c9dt03493e] [Citation(s) in RCA: 1] [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] [Indexed: 11/21/2022]
Abstract
Oxidative C–C coupling of iron-coordinated co-ligand: Iron(ii)-1,4-dihydroxy-2-naphthoate complexes of neutral N4 ligands react with dioxygen to display C–C coupling of 1,4-dihydroxy-2-naphthoate.
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Affiliation(s)
- Rubina Rahaman
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Sandip Munshi
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Sridhar Banerjee
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Biswarup Chakraborty
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Sarmistha Bhunia
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
| | - Tapan Kanti Paine
- School of Chemical Sciences
- Indian Association for the Cultivation of Science
- Kolkata-700032
- India
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13
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Rahaman R, Munshi S, Paine TK. Bio-inspired Oxidation of 1-Aminocarboxylic Acids by a Nonheme Iron(II) Complex: Mimicking the Activity of 1-Aminocyclopropane-1-carboxylic Acid Oxidase. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Rubina Rahaman
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A&2B Raja S. C. Mullick Road 700032 Jadavpur, Kolkata India
| | - Sandip Munshi
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A&2B Raja S. C. Mullick Road 700032 Jadavpur, Kolkata India
| | - Tapan Kanti Paine
- Department of Inorganic Chemistry; Indian Association for the Cultivation of Science; 2A&2B Raja S. C. Mullick Road 700032 Jadavpur, Kolkata India
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14
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Goode SD, Altaf N, Munshi S, MacSweeney STR, Auer DP. Impaired Cerebrovascular Reactivity Predicts Recurrent Symptoms in Patients with Carotid Artery Occlusion: A Hypercapnia BOLD fMRI Study. AJNR Am J Neuroradiol 2016; 37:904-9. [PMID: 27012300 DOI: 10.3174/ajnr.a4739] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 09/01/2015] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE A key factor in predicting recurrent ischemic episodes in patients with carotid artery occlusion is the presence of hemodynamic impairment. There is, however, no consensus on how to best assess this risk in terms of imaging modalities or thresholds used. Here we investigated whether a predefined threshold of hemispheric asymmetry in hypercapnia fMRI predicts recurrent symptoms in patients with carotid artery occlusion. MATERIALS AND METHODS We studied 23 patients (2 women) with a mean age of 67.5 ± 9 years. Patients were assessed for recurrent ischemic events until lost to follow-up, study end, death, or recurrent ischemic event. Hypercapnia fMRI was used to assess the cerebrovascular reserve and quantify the percentage signal change in GM in the MCA territory and the hemispheric asymmetry index. Kaplan-Meier survival analysis and log-rank tests were performed to assess differences between patients with normal or abnormal hemispheric indices. RESULTS The median follow-up was 20 months. During this period, 8 patients experienced recurrent events, and 15 did not. The percentage signal change in GM in the MCA territory was significantly decreased in those patients with recurrent events compared with those without (2.39 ± 0.22 versus 2.70 ± 0.42, P = .032). The normal hemispheric index predicted event-free survival during follow-up (median, 20 months) for both the combined outcome (recurrent events and/or death, log-rank, P = .034) and recurrent retinal or ipsilateral ischemic events only (log-rank, P = .012). CONCLUSIONS The hemispheric asymmetry index derived from hypercapnia fMRI showed hemodynamic impairment in more than half of the studied patients with carotid occlusion, and those patients showed a higher risk of recurrent ischemic symptoms.
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Affiliation(s)
- S D Goode
- From the Sheffield Vascular Institute (S.D.G.), Northern General Hospital, Sheffield, UK Department of Vascular Surgery (S.D.G., N.A., S.T.R.M.), Queens Medical Centre, Nottingham, UK Department of Radiological Sciences (S.D.G., N.A., D.P.A.), Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK.
| | - N Altaf
- Department of Vascular Surgery (S.D.G., N.A., S.T.R.M.), Queens Medical Centre, Nottingham, UK Department of Radiological Sciences (S.D.G., N.A., D.P.A.), Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - S Munshi
- Department of Stroke Medicine (S.M.), Nottingham City Hospital, Nottingham, UK
| | - S T R MacSweeney
- Department of Vascular Surgery (S.D.G., N.A., S.T.R.M.), Queens Medical Centre, Nottingham, UK
| | - D P Auer
- Department of Radiological Sciences (S.D.G., N.A., D.P.A.), Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK.
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15
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Zhou W, Bibila T, Glazomitsky K, Montalyo J, Chan C, Distefano D, Munshi S, Robinson D, Buckland B, Aunins J. Large scale production of recombinant mouse and rat growth hormone by fed-batch GS-NSO cell cultures. Cytotechnology 2012; 22:239-50. [PMID: 22358934 DOI: 10.1007/bf00353944] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Investigations of biological effects of prolonged elevation of growth hormone in animals such as mice and rats require large amounts of mouse and rat growth hormone (GH) materials. As an alternative to scarce and expensive pituitary derived materials, both mouse and rat GH were expressed in NSO murine myeloma cells transfected with a vector containing the glutamine synthetase (GS) gene and two copies of mouse or rat GH cDNA. For optimal expression, the mouse GH vector also contained sequences for targeting integration by homologous recombination. Fed-batch culture processes for such clones were developed using a serum-free, glutamine-free medium and scaled up to 250 L production scale reactors. Concentrated solutions of proteins, amino acids and glucose were fed periodically to extend cell growth and culture lifetime, which led to an increase in the maximum viable cell concentration to 3.5×10(9) cells/L and an up to 10 fold increase in final mouse and rat rGH titers in comparison with batch cultures. For successful scale up, similar culture environmental conditions were maintained at different scales, and specific issues in large scale reactors such as balancing oxygen supply and carbon dioxide removal, were addressed. Very similar cell growth and protein productivity were obtained in the fed-batch cultures at different scales and in different production runs. The final mouse and rat rGH titers were approximately 580 and 240 mg/L, respectively. During fed-batch cultures, the cell growth stage transition was accompanied by a change in cellular metabolism. The specific glucose consumption rate decreased significantly after the transition from the growth to stationary stage, while lactate was produced in the exponential growth stage and became consumed in the stationary stage. This was roughly coincident with the beginning of ammonia and glutamate accumulation at the entry of cells into the stationary stage as the result of a reduced glutamine consumption and periodic nutrient additions.
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Affiliation(s)
- W Zhou
- Merck Research Laboratories, P.O. Box 2000, 07065, Rahway, NJ, USA
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16
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Abstract
The present paper is a venture into the domain of proportional-integral-derivative (PID) -type adaptive fuzzy logic controllers (FLC's) and proposes a new algorithm which is realized by a self-tuned PI-type FLC (in velocity form) in parallel with a self-tuned PD-type FLC (in position form). Each of these PI/PD controllers implements a supervisory static FLC for adaptive online modification of the output scaling factor (SF) of a static PI/PD FLC. The proposed scheme is developed with a view to having a PID-type FLC with an architecture, simple enough for practical implementation, which at the same time has substantially satisfactory performance for a wide class of processes. Simulation studies on a range of processes reveal that the proposed controller has better performance compared to many of its existing counterparts.
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Affiliation(s)
- S Bhattacharya
- Electrical Eng. Dept., Jadavpur University, Calcutta, West Bengal, PIN-700 032, India
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17
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Yan Y, Munshi S, Leiting B, Anderson MS, Chrzas J, Chen Z. Crystal structure of Escherichia coli UDPMurNAc-tripeptide d-alanyl-d-alanine-adding enzyme (MurF) at 2.3 A resolution. J Mol Biol 2000; 304:435-45. [PMID: 11090285 DOI: 10.1006/jmbi.2000.4215] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
MurF is required to catalyze the final step in the synthesis of the cytoplasmic precursor of the bacterial cell wall peptidoglycan, rendering it an attractive target for antibacterial drug development. The crystal structure of the MurF apo-enzyme has been determined using the multiwavelength anomalous dispersion method and refined to 2.3 A resolution. It contains three consecutive open alpha/beta-sheet domains. In comparison with the complex crystal structures of MurD and its substrates, The topology of the N-terminal domain of MurF is unique, while its central and C-terminal domains exhibit similar mononucleotide and dinucleotide-binding folds, respectively. The apo-enzyme of MurF crystal structure reveals an open conformation with the three domains juxtaposed in a crescent-like arrangement creating a wide-open space where substrates are expected to bind. As such, catalysis is not feasible and significant domain closure is expected upon substrate binding.
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Affiliation(s)
- Y Yan
- Department of Structural Biology, West Point, PA, 19486, USA.
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18
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Munshi S, Chen Z, Yan Y, Li Y, Olsen DB, Schock HB, Galvin BB, Dorsey B, Kuo LC. An alternate binding site for the P1-P3 group of a class of potent HIV-1 protease inhibitors as a result of concerted structural change in the 80s loop of the protease. Acta Crystallogr D Biol Crystallogr 2000; 56:381-8. [PMID: 10739910 DOI: 10.1107/s0907444900000469] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Structures of the complexes of HIV protease inhibitor L--756,423 with the HIV-1 wild-type protease and of the inhibitors Indinavir, L-739,622 and Saquinavir with the mutant protease (9X) containing nine point mutations (Leu10Val, Lys20Met, Leu24Ile, Ser37Asp, Met46Ile, Ile54Val, Leu63Pro, Ala71Val, Val82Thr) have been determined. Comparative analysis of these structures reveals an alternate binding pocket for the P1-P3 group of Indinavir and L--756, 423. The alternate binding pocket is a result of concerted structural change in the 80s loop (residues 79-82) of the protease. The 80s loop is pulled away from the active site in order to accommodate the P1-P3 group, which is sandwiched between the flap and the 80s loop. This structural change is observed for the complexes of the wild type as well as the 9X mutant protease. The study reveals that the 80s loop is an intrinsically flexible loop in the wild-type HIV-1 protease and that mutations in this loop are not necessary to result in conformational changes. Conformation of this loop in the complex depends primarily upon the nature of the bound inhibitor and may be influenced by mutations in the protease. The results underscore the need to understand the intrinsic structural plasticity of the protease for the design of effective inhibitors against the wild-type and drug-resistant enzyme forms. In addition, the alternate binding pocket for the P1-P3 group of Indinavir and L--756,423 may be exploited for the design of potent inhibitors.
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Affiliation(s)
- S Munshi
- Department of Antiviral Research, Merck Research Laboratories, West Point, PA 19486, USA.
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19
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Chen Z, Yan Y, Munshi S, Li Y, Zugay-Murphy J, Xu B, Witmer M, Felock P, Wolfe A, Sardana V, Emini EA, Hazuda D, Kuo LC. X-ray structure of simian immunodeficiency virus integrase containing the core and C-terminal domain (residues 50-293)--an initial glance of the viral DNA binding platform. J Mol Biol 2000; 296:521-33. [PMID: 10669606 DOI: 10.1006/jmbi.1999.3451] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The crystal structure of simian immunodeficiency virus (SIV) integrase that contains in a single polypeptide the core and the C-terminal deoxyoligonucleotide binding domain has been determined at 3 A resolution with an R-value of 0.203 in the space group P2(1)2(1)2(1). Four integrase core domains and one C-terminal domain are found to be well defined in the asymmetric unit. The segment extending from residues 114 to 121 assumes the same position as seen in the integrase core domain of avian sarcoma virus as well as human immunodeficiency virus type-1 (HIV-1) crystallized in the absence of sodium cacodylate. The flexible loop in the active site, composed of residues 141-151, remains incompletely defined, but the location of the essential Glu152 residue is unambiguous. The residues from 210-218 that link the core and C-terminal domains can be traced as an extension from the core with a short gap at residues 214-215. The C(alpha) folding of the C-terminal domain is similar to the solution structure of this domain from HIV-1 integrase. However, the dimeric form seen in the NMR structure cannot exist as related by the non-crystallographic symmetry in the SIV integrase crystal. The two flexible loops of the C-terminal domain, residues 228-236 and residues 244-249, are much better fixed in the crystal structure than in the NMR structure with the former in the immediate vicinity of the flexible loop of the core domain. The interface between the two domains encompasses a solvent-exclusion area of 1500 A(2). Residues from both domains purportedly involved in DNA binding are narrowly distributed on the same face of the molecule. They include Asp64, Asp116, Glu152 and Lys159 from the core and Arg231, Leu234, Arg262, Arg263 and Lys264 from the C-terminal domain. A model for DNA binding is proposed to bridge the two domains by tethering the 228-236 loop of the C-terminal domain and the flexible loop of the core.
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Affiliation(s)
- Z Chen
- Department of Antiviral Research, Merck Research Laboratories, West Point, PA, 19486-0004, USA
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20
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Yan Y, Munshi S, Li Y, Pryor KA, Marsilio F, Leiting B. Crystallization and preliminary X-ray analysis of the Escherichia coli UDP-MurNAc-tripeptide D-alanyl-D-alanine-adding enzyme (MurF). Acta Crystallogr D Biol Crystallogr 1999; 55:2033-4. [PMID: 10666581 DOI: 10.1107/s0907444999011786] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Crystals of the Escherichia coli UDP-MurNAc-tripeptide D-Ala-D-Ala-adding protein (MurF), which catalyzes the formation of the last metabolite of the bacterial cell-wall building block, have been grown in hanging-drop vapor-diffusion trials using PEG 8K as a precipitating agent. The crystals belong to hexagonal space group P6(1) or P6(5), with unit-cell dimensions a = b = 74, c = 425 A. The asymmetric unit contains two molecules, with a crystal volume per protein mass (V(m)) of 3.4 A(3) Da(-1) and a solvent content of about 64% by volume. A native data set to 2.8 A resolution has been obtained from a frozen crystal using a synchrotron X-ray source.
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Affiliation(s)
- Y Yan
- Department of Antiviral Research, Merck Research Laboratories, West Point, PA 19486, USA
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21
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Liang X, Munshi S, Shendure J, Mark G, Davies ME, Freed DC, Montefiori DC, Shiver JW. Epitope insertion into variable loops of HIV-1 gp120 as a potential means to improve immunogenicity of viral envelope protein. Vaccine 1999; 17:2862-72. [PMID: 10438057 DOI: 10.1016/s0264-410x(99)00125-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report on the properties of a set of HIV-1 IIIB Env mutants carrying a linear gp41 epitope insertion (LLELDKWASL) in the V1, V2, V3 or V4 variable loop. Insertion of the epitope, which is defined by the HIV-1 neutralizing MAb 2F5, was well tolerated in the V1, V2 and V4 loops, as these mutants were properly expressed, retained reactivity to conformation-dependent monoclonal antibodies and exhibited patterns similar to the parental Env molecule. However, insertion of this epitope in the V3 loop was associated with drastically reduced protein expression. Relative to parental Env molecule, the V1, V2 and V4 insertion mutants demonstrated significantly increased binding to mAb 2F5 in vitro. To evaluate immunogenicity, mice and guinea pigs were immunized with plasmid expression vectors for the mutant proteins. For both mice and guinea pigs, all four mutants elicited anti-gp120 antibody responses. In mice the V1 and V3 insertion mutants, but neither the V2 or V4 insertion mutant nor the parental env, elicited significant titers against the epitope peptide, whereas in guinea pigs, V2 insertion mutant was most effective in eliciting anti-2F5 peptide antibody responses. While original V2 2F5 insertion mutant failed to elicit anti-2F5 peptide responses in mice, studies with 14 additional V2 insertion mutants revealed several insertion sites at which the epitope was able to induce epitope-specific antibody responses. This indicates that the precise position at which the epitope insertion takes place dictates the ability of the mutant to induce the epitope-specific antibody responses. When tested for virus neutralization activity, the guinea pig sera that contain high titers of anti-2F5 peptide antibody failed to enhance the virus neutralizing activity, suggesting that the configuration of 2F5 epitope plays a critical role in inducing neutralizing antibody responses. The results from this study may have potential implications with respect to modification of the HIV-1 Env molecule for the purpose of improving HIV-1 Env immunogenicity.
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Affiliation(s)
- X Liang
- Department of Virus and Cell Biology, Merck Research Laboratories, Westpoint, PA 19486, USA.
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22
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Abstract
The structure of Nudaurelia capensis omega virus (NomegaV), a single-stranded RNA virus, was determined to 2.8 A resolution. Triclinic crystals (a = 413.6, b = 410.2, c = 419.7 A, alpha = 59.13, beta = 58.9, gamma = 64.0 degrees ) diffracted X-rays beyond 2.7 A resolution. The unit cell contained one icosahedral virus particle, providing 60-fold non-crystallographic symmetry (n.c.s.) and structural redundancy. The particle orientation in the unit cell was determined by self-rotation function analyses. Initial phases to 18 A resolution were derived from a hollow spherical model of 192 A outer radius and 139 A inner radius, filled with uniform electron density. Radii of the model were determined by maximizing the correlation of the model-based calculated data with the low-resolution X-ray diffraction and solution-scattering data. Phases were refined by 60-fold non-crystallographic electron-density averaging and extended in small steps to a resolution of 5 A. The phases obtained represented a mixture of four different phase sets, each consistent with the icosahedral symmetry constraints. The resulting electron density was not interpretable. A difference Fourier map computed with the native and an isomorphous heavy-atom derivative data sets and phases refined by real-space averaging was interpretable only if data within the 10 A resolution shell were used. Maps calculated with data significantly higher than 10 A resolution failed to display a constellation of heavy-atom sites consistent with the T = 4 icosahedral symmetry. Attempts to extend the phases beyond 10 A resolution, starting with either phases based on a model or single isomorphous replacement, were unsuccessful. Successful phase extension was achieved by computing the phases for the higher resolution reflections from a partial atomic model (poly gly) built into the averaged 10 A electron-density map. Phases from this model served as the starting point for n.c.s. phase refinement and extension to slightly higher resolution. The atomic model was improved at each extension interval and these phases were used for the subsequent phase calculation and extension. The entire polypeptide backbone corresponding to the NomegaV structure was built into the map at 4 A. The same procedure for phase refinement was used to extend the phases to 2.8 A in small increments of resolution. The overall molecular averaging R factor and correlation coefficient at 2.8 A resolution were 18.4% and 0.87, respectively.
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Affiliation(s)
- S Munshi
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, LaJolla, California 92037, USA
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23
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Munshi S, Chen Z, Li Y, Olsen DB, Fraley ME, Hungate RW, Kuo LC. Rapid X-ray diffraction analysis of HIV-1 protease-inhibitor complexes: inhibitor exchange in single crystals of the bound enzyme. Acta Crystallogr D Biol Crystallogr 1998; 54:1053-60. [PMID: 9757136 DOI: 10.1107/s0907444998003588] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ability to replace an inhibitor bound to the HIV-1 protease in single crystals with other potent inhibitors offers the possibility of investigating a series of protease inhibitors rapidly and conveniently with the use of X-ray crystallography. This approach affords a fast turnaround of structural information for iterative rational drug designs and obviates the need for studying the complex structures by co-crystallization. The replacement approach has been successfully used with single crystals of the HIV-1 protease complexed with a weak inhibitor. The structures of the complexes obtained by the replacement method are similar to those determined by co-crystallization.
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Affiliation(s)
- S Munshi
- Department of Antiviral Research, Merck Research Laboratories, West Point, PA 19486, USA
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24
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Martin SF, Dorsey GO, Gane T, Hillier MC, Kessler H, Baur M, Mathä B, Erickson JW, Bhat TN, Munshi S, Gulnik SV, Topol IA. Cyclopropane-derived peptidomimetics. Design, synthesis, evaluation, and structure of novel HIV-1 protease inhibitors. J Med Chem 1998; 41:1581-97. [PMID: 9572884 DOI: 10.1021/jm980033d] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Toward establishing the general efficacy of using trisubstituted cyclopropanes as peptide mimics to stabilize extended peptide structures, the cyclopropanes 20a-d were incorporated as replacements into 9-13, which are analogues of the known HIV-1 protease inhibitors 14 and 15. The syntheses of 20a-d commenced with the Rh2[5(S)-MEPY]4-catalyzed cyclization of the allylic diazoesters 16a-d to give the cyclopropyl lactones 17a-d in high enantiomeric excess. Opening of the lactone moiety using the Weinreb protocol and straightforward refunctionalization of the intermediate amides 18a-d gave 20a-d. A similar sequence of reactions was used to prepare the N-methyl-2-pyridyl analogue 28. Coupling of 20a-d and 28 with the known diamino diol 22 delivered 9-13. Pseudopeptides 9-12 were found to be competitive inhibitors of wild-type HIV-1 protease in biological assays having Kis of 0.31-0.35 nM for 9, 0.16-0.21 nM for 10, 0.47 nM for 11, and 0.17 nM for 12; these inhibitors were thus approximately equipotent to the known inhibitor 14(IC50 = 0.22 nM) from which they were derived. On the other hand 13 (Ki = 80 nM) was a weaker inhibitor than its analogue 15 (Ki = 0.11 nM). The solution structures of 9 and 10 were analyzed by NMR spectroscopy and simulated annealing procedures that included restraints derived from homo- and heteronuclear coupling constants and NOEs; because of the molecular symmetry of9 and 10, a special protocol to treat the NOE data was used. The final structure was checked by restrained and free molecular dynamic calculations using an explicit DMSO solvent box. The preferred solution conformations of 9 and 10 are extended structures that closely resemble the three-dimensional structure of 10 bound to HIV-1 protease as determined by X-ray crystallographic analysis of the complex. This work convincingly demonstrates that extended structures of peptides may be stabilized by the presence of substituted cyclopropanes that serve as peptide replacements. Moreover, the linear structure enforced in solution by the two cyclopropane rings in the pseudopeptides 9-12 appears to correspond closely to the biologically active conformation of the more flexible inhibitors 14 and 15. The present work, which is a combination of medicinal, structural, and quantum chemistry, thus clearly establishes that cyclopropanes may be used as structural constraints to reduce the flexibility of linear pseudopeptides and to help enforce the biologically active conformation of such ligands in solution.
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Affiliation(s)
- S F Martin
- Structural Biochemistry Program, Frederick Biomedical Supercomputing Center, NCI-FCRDC, Frederick, Maryland 21702, USA
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25
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Yan Y, Li Y, Munshi S, Sardana V, Cole JL, Sardana M, Steinkuehler C, Tomei L, De Francesco R, Kuo LC, Chen Z. Complex of NS3 protease and NS4A peptide of BK strain hepatitis C virus: a 2.2 A resolution structure in a hexagonal crystal form. Protein Sci 1998; 7:837-47. [PMID: 9568891 PMCID: PMC2143993 DOI: 10.1002/pro.5560070402] [Citation(s) in RCA: 216] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The crystal structure of the NS3 protease of the hepatitis C virus (BK strain) has been determined in the space group P6(3)22 to a resolution of 2.2 A. This protease is bound with a 14-mer peptide representing the central region of the NS4A protein. There are two molecules of the NS3(1-180)-NS4A(21'-34') complex per asymmetric unit. Each displays a familiar chymotrypsin-like fold that includes two beta-barrel domains and four short alpha-helices. The catalytic triad (Ser-139, His-57, and Asp-81) is located in the crevice between the beta-barrel domains. The NS4A peptide forms an almost completely enclosed peptide surface association with the protease. In contrast to the reported H strain complex of NS3 protease-NS4A peptide in a trigonal crystal form (Kim JL et al., 1996, Cell 87:343-355), the N-terminus of the NS3 protease is well-ordered in both molecules in the asymmetric unit of our hexagonal crystal form. The folding of the N-terminal region of the NS3 protease is due to the formation of a three-helix bundle as a result of crystal packing. When compared with the unbound structure (Love RA et al., 1996, Cell 87:331-342), the binding of the NS4A peptide leads to the ordering of the N-terminal 28 residues of the NS3 protease into a beta-strand and an alpha-helix and also causes local rearrangements important for a catalytically favorable conformation at the active site. Our analysis provides experimental support for the proposal that binding of an NS4A-mimicking peptide, which increases catalytic rates, is necessary but not sufficient for formation of a well-ordered, compact and, hence, highly active protease molecule.
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Affiliation(s)
- Y Yan
- Department of Antiviral Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA
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26
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Zlotnick A, Natarajan P, Munshi S, Johnson JE. Resolution of Space-Group Ambiguity and Structure Determination of Nodamura Virus to 3.3 Å resolution from Pseudo-R32 (Monoclinic) Crystals. Acta Crystallogr D Biol Crystallogr 1997; 53:738-46. [PMID: 15299863 DOI: 10.1107/s0907444997007427] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Monoclinic crystals of nodamura virus (NOV) have two virus molecules per asymmetric unit. Packing analysis reveals a pseudo-rhombohedral (pseudo-C2 monoclinic) arrangement of particles in the actual P2(1) space group (a = 562.1, b = 354.1, c = 612.8 A, beta = 110.9 degrees ). The R32 symmetry is broken rotationally and translationally. The pseudo-symmetry of the unit cell results in three possible monoclinic origins and also restrains the four particles in the unit cell to similar orientations. NOV particles deviate by less than 3 degrees from the ideal orientations, causing overlap of peaks in the rotation function and the generation of peaks that were not interpretable as particle symmetry elements. The space-group ambiguity was resolved by analysing the relationship between the particle orientations determined by high-resolution rotation functions and the attenuation of peak heights in native Patterson maps. Particles were centered less than 1 A from the R32 special positions. Three different approaches were required to identify the correct particle center. Following the solutions of the rotation and translation problems, phases were computed using the coordinates of flock house virus (FHV), another member of this virus family. The phases were improved by real-space molecular averaging with a 120-fold non-crystallographic symmetry and by solvent flattening with a spherical mask. The final model for the NOV structure was built using the 3.3 A averaged map. While the overall subunit structure was very similar to that of other nodaviruses, FHV and black beetle virus, NOV showed distinct structural features near particle threefold and quasi-threefold axes and at the protein-RNA interfaces that are consistent with phenotype differences among the related viruses.
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Affiliation(s)
- A Zlotnick
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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Chandrasekar V, Munshi S, Johnson JE. Crystallization and preliminary X-ray analysis of tobacco ringspot virus. Acta Crystallogr D Biol Crystallogr 1997; 53:125-8. [PMID: 15299983 DOI: 10.1107/s0907444996011547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Tobacco ringspot virus, a plant virus that is believed to fill an apparent niche in the evolution of picornavirus-like capsids, has been crystallized by vapor diffusion with potassium phosphate and polyethylene glycol buffered at pH 6.5 in a new crystal form. The monoclinic crystals belong to the space group C2 with unit-cell dimensions of a = 407.1, b = 399.7, c = 285.9 A and beta = 129.1 degrees and diffract synchrotron radiation to 3.3 A. One half of a virus particle constitutes the crystallographic asymmetric unit. The orientation of the virus particle in the unit cell was determined by the rotation function analysis of a partial data set that has been collected at CHESS using image plates. Development of a suitable phasing model for the high-resolution structure determination of TRSV with the real-space molecular replacement technique is now under way.
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Affiliation(s)
- V Chandrasekar
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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Munshi S, Liljas L, Cavarelli J, Bomu W, McKinney B, Reddy V, Johnson JE. The 2.8 A structure of a T = 4 animal virus and its implications for membrane translocation of RNA. J Mol Biol 1996; 261:1-10. [PMID: 8760498 DOI: 10.1006/jmbi.1996.0437] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.2] [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: 02/02/2023]
Abstract
Simple RNA animal viruses generally enter cells through receptor-mediated endocytosis followed by acid pH dependent release and translocation of RNA across the endosomal membrane. The T = 3 nodaviruses contain prefabricated pentameric helical bundles that are cleaved from the remainder of the subunits by an assembly-dependent auto-proteolysis and they are positioned for release through 5-fold axes of the particle. We previously proposed that these bundles may serve as conduits for RNA membrane translocation. Additional support for this hypothesis is now provided by the first atomic resolution structure of a T = 4 RNA virus, where we find cleavage sites and helical bundles nearly identical with those observed in T = 3 nodaviruses. The helices are of sufficient length to span a membrane bilayer and the internal diameter of the coiled bundle could accommodate ssRNA. The T = 4 particle has a mean outer diameter of 410 A and is formed by 240 copies of a single subunit type. The subunit is composed of a helical inner domain (where the cleavage occurs) containing residues preceding and following a canonical, viral, eight-stranded beta-sandwich that forms the contiguous shell. Inserted between two strands of the shell domain are 133 residues with an immunoglobulin c-type fold. The initial gene product consists of 644 amino acid residues and is cleaved between residues Asn570 and Phe571 in the mature particle determined in this analysis.
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Affiliation(s)
- S Munshi
- Department of Biological Sciences, Purdue University West Lafayette, Indiana 47907-1392, USA
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Li Y, Yan Y, Munshi S, Hall D, Waxman L, Darke P, Kuo L, Chen Z. Preliminary crystallographic studies of the human cytomegalovirus protease. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396089519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Bhat TN, Randad RS, Lee AY, Lubkowska L, Munshi S, Yu B, Gulnik S, Collins PJ, Erickson JW. Structural studies of inhibitor complexes of HIV-1 protease and of its drug resistance mutants. Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396091283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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31
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Chapman M, Tsao J, Rossmann M, Munshi S, Johnson J. Ab initiophase determination for viruses: the use of non-crystallographic symmetry for phase refinement. Acta Crystallogr A 1996. [DOI: 10.1107/s010876739609650x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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32
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DiStefano DJ, Gould SL, Munshi S, Robinson DK. Titration of human-bovine rotavirus reassortants using a tetrazolium-based colorimetric end-point dilution assay. J Virol Methods 1995; 55:199-208. [PMID: 8537458 DOI: 10.1016/0166-0934(95)00057-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A colorimetric end-point dilution assay was developed for the titration of rotavirus-containing samples that uses commercially available tetrazolium dyes as an indicator of virus infection. This assay offers several advantages over both plaque assays and traditional end-point dilution methods. The latter assays require manual counting of plaques or the scoring of wells for the presence of virus based on observed cytopathic effects. The colorimetric end-point dilution assay enables the scoring of wells based upon absorbance readings alone, thereby eliminating time-consuming and subjective manual screenings. This method also has the potential for automating the analysis of large numbers of samples. Virus titers of human-bovine rotavirus reassortants obtained using this method are comparable to those determined by plaque assay. The scoring of wells based on absorbance readings was also found to agree with manual scoring of cytopathic effects and with the production of viral antigen.
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Affiliation(s)
- D J DiStefano
- Department of Cellular and Molecular Biology, Merck Research Laboratories, Rahway, NJ 07065, USA
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Cornea-Hasegan MA, Zhang Z, Lynch RE, Marinescu DC, Hadfield A, Muckelbauer JK, Munshi S, Tong L, Rossmann MG. Phase refinement and extension by means of non-crystallographic symmetry averaging using parallel computers. Acta Crystallogr D Biol Crystallogr 1995; 51:749-59. [PMID: 15299805 DOI: 10.1107/s0907444995001399] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Electron-density averaging, fast Fourier synthesis and fast Fourier analysis programs have been adapted for parallel-computing systems. These have been linked to perform iterative phase improvement and extension utilizing non-crystallographic symmetry and solvent flattening. Various strategies for parallel algorithms have been tested on a variety of computers as a function of the number of computer nodes. Some experimental timing results are discussed.
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Affiliation(s)
- M A Cornea-Hasegan
- Department of Computer Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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Kiyatkin AB, Natarajan P, Munshi S, Minor W, Johnson JE, Low PS. Crystallization and preliminary X-ray analysis of the cytoplasmic domain of human erythrocyte band 3. Proteins 1995; 22:293-7. [PMID: 7479704 DOI: 10.1002/prot.340220312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 01/25/2023]
Abstract
A cytoplasmic domain of the human erythrocyte membrane protein band 3 (M(r) = 42,500), residues 1-379, expressed in and purified from E. coli, has been crystallized by the method of vapor diffusion in sitting drops with subsequent streak-seeding at room temperature. Initial crystals were grown from solutions containing 65-68% saturated ammonium sulfate at pH 4.9 and 2 mg/ml protein. Subsequent streak-seeding into solutions of 50-53% ammonium sulfate at pH 4.9 and 7 mg/ml protein produced single crystals suitable for X-ray analysis, which contained pure protein as revealed by gel electrophoresis. The crystals belong to the monoclinic space group C2 with cell dimensions of a = 178.8 A, b = 90.5 A, c = 122.1 A, and beta = 131.3 degrees and diffract at least to 2.7 A resolution (at 100 K). A self-rotation function shows the presence of approximate 222 local symmetry.
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Affiliation(s)
- A B Kiyatkin
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA
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Speir JA, Munshi S, Wang G, Baker TS, Johnson JE. Structures of the native and swollen forms of cowpea chlorotic mottle virus determined by X-ray crystallography and cryo-electron microscopy. Structure 1995; 3:63-78. [PMID: 7743132 PMCID: PMC4191737 DOI: 10.1016/s0969-2126(01)00135-6] [Citation(s) in RCA: 517] [Impact Index Per Article: 17.8] [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: 01/26/2023]
Abstract
BACKGROUND RNA-protein interactions stabilize many viruses and also the nucleoprotein cores of enveloped animal viruses (e.g. retroviruses). The nucleoprotein particles are frequently pleomorphic and generally unstable due to the lack of strong protein-protein interactions in their capsids. Principles governing their structures are unknown because crystals of such nucleoprotein particles that diffract to high resolution have not previously been produced. Cowpea chlorotic mottle virions (CCMV) are typical of particles stabilized by RNA-protein interactions and it has been found that crystals that diffract beyond 4.5 A resolution are difficult to grow. However, we report here the purification of CCMV with an exceptionally mild procedure and the growth of crystals that diffract X-rays to 3.2 A resolution. RESULTS The 3.2 A X-ray structure of native CCMV, an icosahedral (T = 3) RNA plant virus, shows novel quaternary structure interactions based on interwoven carboxyterminal polypeptides that extend from canonical capsid beta-barrel subunits. Additional particle stability is provided by intercapsomere contacts between metal ion mediated carboxyl cages and by protein interactions with regions of ordered RNA. The structure of a metal-free, swollen form of the virus was determined by cryo-electron microscopy and image reconstruction. Modeling of this structure with the X-ray coordinates of the native subunits shows that the 29 A radial expansion is due to electrostatic repulsion at the carboxyl cages and is stopped short of complete disassembly by preservation of interwoven carboxyl termini and protein-RNA contacts. CONCLUSIONS The CCMV capsid displays quaternary structural interactions that are unique compared with previously determined RNA virus structures. The loosely coupled hexamer and pentamer morphological units readily explain their versatile reassembly properties and the pH and metal ion dependent polymorphism observed in the virions. Association of capsomeres through inter-penetrating carboxy-terminal portions of the subunit polypeptides has been previously described only for the DNA tumor viruses, SV40 and polyoma.
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Affiliation(s)
- J A Speir
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA
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Robinson DK, Seamans TC, Gould SL, DiStefano DJ, Chan CP, Lee DK, Bibila T, Glazomitsky K, Munshi S, Daugherty B. Optimization of a fed-batch process for production of a recombinant antibody. Ann N Y Acad Sci 1994; 745:285-96. [PMID: 7832519 DOI: 10.1111/j.1749-6632.1994.tb44383.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- D K Robinson
- Merck Research Laboratories, Rahway, New Jersey 07065
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Johnson JE, Munshi S, Liljas L, Agrawal D, Olson NH, Reddy V, Fisher A, McKinney B, Schmidt T, Baker TS. Comparative studies of T = 3 and T = 4 icosahedral RNA insect viruses. Arch Virol Suppl 1994; 9:497-512. [PMID: 8032278 PMCID: PMC4167711 DOI: 10.1007/978-3-7091-9326-6_48] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Crystallographic and molecular biological studies of T = 3 nodaviruses (180 identical subunits in the particle) and T = 4 tetraviruses (240 identical subunits in the particle) have revealed similarity in both the architecture of the particles and the strategy for maturation. The comparative studies provide a novel opportunity to examine an apparent evolution of particle size, from smaller (T = 3) to larger (T = 4), with both particles based on similar subunits. The BBV and FHV nodavirus structures are refined at 2.8 A and 3 A respectively, while the N omega V structure is at 6 A resolution. Nevertheless, the detailed comparisons of the noda and tetravirus X-ray electron density maps show that the same type of switching in subunit twofold contacts is used in the T = 3 and T = 4 capsids, although differences must exist between quasi and icosahedral threefold contacts in the T = 4 particle that have not yet been detected. The analyses of primary and tertiary structures of noda and tetraviruses show that N omega V subunits undergo a post assembly cleavage like that observed in nodaviruses and that the cleaved 76 C-terminal residues remain associated with the particle.
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Affiliation(s)
- J E Johnson
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana
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Zlotnick A, McKinney BR, Munshi S, Bibler J, Rossmann MG, Johnson JE. A monoclinic crystal with R32 pseudo-symmetry: a preliminary report of Nodamura virus structure determination. Acta Crystallogr D Biol Crystallogr 1993; 49:580-7. [PMID: 15299495 DOI: 10.1107/s0907444993007498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have crystallized Nodamura virus, a T = 3 icosahedral virus that can infect both mammalian and insect hosts. Crystals are monoclinic, with two crystallographically independent virus molecules per asymmetric unit. Packing analysis reveals a pseudo-rhombohedral (pseudo-C2 in the monoclinic setting) arrangement of virus particles in the crystal lattice. Crystals differ from the R32 symmetry by rotational and translational deviations. The rhombohedral packing arrangement and its failure to describe the exact virus packing is analyzed in detail. The icosahedral threefold axis is rotated from the body diagonal of the pseudo-rhombohedral cell, breaking the rhombohedral symmetry. The C2 pseudo-symmetry breaks down rotationally and/or translationally.
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Affiliation(s)
- A Zlotnick
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
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Abstract
Crystals of cowpea chlorotic mottle virus (CCMV) that diffract X-rays to 3.1 A resolution were grown in a succinate-PEG solution buffered at pH 3.3. The crystals are in space group P2(1)2(1)2(1) with unit cell dimensions of a = 381.26 A, b = 381.26 A, and c = 408.59 A. Four particles occupy the unit cell, placing a single virion in the crystallographic asymmetric unit. Diffraction intensities measured from 196 films collected at the Cornell High Energy Synchrotron Source accounted for 55% of the theoretically possible data to 3.2 A. Unit cell dimensions and rotation function analyses of the X-ray data revealed that the particles were organized in a pseudo-tetragonal relationship with the pseudo-fourfold axis along the crystal c axis. Analysis of electron micrographs of two-dimensional crystals of CCMV revealed a remarkable similarity between these and planes of particles perpendicular to the crystallographic c axis in the three-dimensional crystal.
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Affiliation(s)
- J A Speir
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
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Cavarelli J, Bomu W, Liljas L, Kim S, Minor W, Munshi S, Muchmore S, Schmidt T, Johnson J, Hendry DA. Crystallization and preliminary structure analysis of an insect virus with T=4 quasi-symmetry: Nudaurelia capensis ω virus. Acta Crystallogr B Struct Sci 1991. [DOI: 10.1107/s0108768190009326] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
The prevalence of peptic ulcer disease in the general population of Kashmir, India, was determined by endoscopy in a randomly selected sample population of 2763 adults aged 15 years and above who were interviewed using a questionnaire. Of 239 persons with ulcer symptoms, 193 (80.7%) had an oesophagogastroduodenoscopy. A randomly selected 177 individuals from among the remaining population without ulcer symptoms, were also endoscoped. The point prevalence of peptic ulcer was 4.72% and the lifetime prevalence was 11.22%. The duodenal to gastric ulcer ratio was 17.1:1. Duodenal and gastric ulcer were common in men. The prevalence of peptic ulcer increased with age, with a peak prevalence of 28.8% in the 5th decade of life. Peptic ulcer was not related to socio-economic status. The prevalence of complications, such as bleeding, stenosis, or perforation were similar to those reported in the West.
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Affiliation(s)
- M S Khuroo
- Department of Gastroenterology, Sher-i-Kashmir, Institute of Medical Sciences, India
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Whang Y, Silberklang M, Morgan A, Munshi S, Lenny AB, Ellis RW, Kieff E. Expression of the Epstein-Barr virus gp350/220 gene in rodent and primate cells. J Virol 1987; 61:1796-807. [PMID: 3033311 PMCID: PMC254182 DOI: 10.1128/jvi.61.6.1796-1807.1987] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The gene encoding the Epstein-Barr virus envelope glycoproteins gp350 and gp220 was inserted downstream of the cytomegalovirus immediate-early, Moloney murine leukemia virus, mouse mammary tumor virus, or varicella-zoster virus gpI promoters in vectors containing selectable markers. Host cell and recombinant vector systems were defined which enabled the isolation of rodent or primate cell clones which expressed gp350/220 in substantial quantities. Continued expression of gp350/220 required maintenance of cells under positive selection for linked markers and periodic cloning. gp350/220 expressed in various host cells varied slightly in electrophoretic mobility, probably reflecting differences in glycosylation. Insertion of a stop codon into the gp350/220 open reading frame, upstream of the putative membrane anchor sequence, resulted in efficient secretion of truncated gp350 and gp220 from rat pituitary (GH3) cells. gp350/220 expressed in mammalian cells is highly immunogenic and elicits virus-neutralizing antibodies when administered to mice.
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Webb DR, Munshi S, Banerjee AK. Replication of vesicular stomatitis virus in murine spleen cells: enrichment of the virus-replicating lymphocytes and analysis of replication restriction. Infect Immun 1981; 32:169-72. [PMID: 6260680 PMCID: PMC350602 DOI: 10.1128/iai.32.1.169-172.1981] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Vesicular stomatitis virus (Indiana strain) will only grow in T lymphocytes which have been stimulated to undergo cell division. Evidence is presented that a considerable enrichment of the vesicular stomatitis virus-replicating T cells may be accomplished in the mouse spleen by passing the spleen cells over glass wool columns. By using this procedure experiments were performed to study the nature of the block in vesicular stomatitis virus replication in unstimulated (nonpermissive) versus mitogen-stimulated (permissive) splenic T cells. The results show that, as is the case in permissive T-cell lines, stimulated normal T cells allow the synthesis of the 42S virion ribonucleic acid.
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