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Larsoliver Essen - One of the best experts on this subject based on the ideXlab platform.
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struCtural and funCtional insights into a peptide bond forming bidomain from a nonribosomal peptide synthetase
Structure, 2007Co-Authors: Stefan A Samel, Georg Schoenafinger, Thomas A Knappe, Moharned A. Marahiel, Larsoliver EssenAbstract:Summary The Crystal struCture of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyroCidine synthetase TyCC was determined at 1.8 A resolution. The bidomain struCture reveals a V-shaped Condensation domain, the Canyon-like aCtive site groove of whiCh is assoCiated with the preCeding peptidyl Carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming Condensation (C) domain plaCes the aCtive sites ∼50 A apart. ACCordingly, this PCP-C struCture represents a Conformational state prior to peptide transfer from the donor-PCP to the aCCeptor-PCP domain, implying the existenCe of additional states of PCP-C domain interaCtion during Catalysis. Additionally, PCP-C exerts a mode of CyClization aCtivity that mimiCs peptide bond formation Catalyzed by C domains. Based on mutational data and pK value analysis of aCtive site residues, it is suggested that nonribosomal peptide bond formation depends on eleCtrostatiC interaCtions rather than on general aCid/base Catalysis.
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struCtural and funCtional insights into a peptide bond forming bidomain from a nonribosomal peptide synthetase
Structure, 2007Co-Authors: Stefan A Samel, Georg Schoenafinger, Thomas A Knappe, Moharned A. Marahiel, Larsoliver EssenAbstract:The Crystal struCture of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyroCidine synthetase TyCC was determined at 1.8 A resolution. The bidomain struCture reveals a V-shaped Condensation domain, the Canyon-like aCtive site groove of whiCh is assoCiated with the preCeding peptidyl Carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming Condensation (C) domain plaCes the aCtive sites approximately 50 A apart. ACCordingly, this PCP-C struCture represents a Conformational state prior to peptide transfer from the donor-PCP to the aCCeptor-PCP domain, implying the existenCe of additional states of PCP-C domain interaCtion during Catalysis. Additionally, PCP-C exerts a mode of CyClization aCtivity that mimiCs peptide bond formation Catalyzed by C domains. Based on mutational data and pK value analysis of aCtive site residues, it is suggested that nonribosomal peptide bond formation depends on eleCtrostatiC interaCtions rather than on general aCid/base Catalysis.
James E Thomson - One of the best experts on this subject based on the ideXlab platform.
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asymmetriC synthesis of n o diaCetyl 3 epi xestoaminol C struCture and absolute Configuration Confirmation of 3 epi xestoaminol C
Tetrahedron Letters, 2016Co-Authors: Susanna G Archer, Kristina Csatayova, Stephen G Davies, Ai M Fletcher, Paul M Roberts, James E ThomsonAbstract:The asymmetriC synthesis of N , O -diaCetyl-3- epi -xestoaminol C is reported. The synthesis employs diastereoseleCtive aminohydroxylation of tert -butyl Crotonate [Conjugate addition of lithium ( S )- N -benzyl- N -(α-methylbenzyl)amide, then in situ enolate oxidation with (+)-Camphorsulfonyloxaziridine (CSO)] and a diastereoseleCtive reduCtion protoCol as the key stereodefining steps. The synthetiC sample of the natural produCt was isolated as its N , O -diaCetyl derivative for ease of purifiCation; this material was prepared in ten steps and 17% overall yield from CommerCially available tert -butyl Crotonate. This synthesis Confirms unambiguously both the assigned struCture and absolute ( S , S )-Configuration of the natural produCt.
Stefan A Samel - One of the best experts on this subject based on the ideXlab platform.
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struCtural and funCtional insights into a peptide bond forming bidomain from a nonribosomal peptide synthetase
Structure, 2007Co-Authors: Stefan A Samel, Georg Schoenafinger, Thomas A Knappe, Moharned A. Marahiel, Larsoliver EssenAbstract:Summary The Crystal struCture of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyroCidine synthetase TyCC was determined at 1.8 A resolution. The bidomain struCture reveals a V-shaped Condensation domain, the Canyon-like aCtive site groove of whiCh is assoCiated with the preCeding peptidyl Carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming Condensation (C) domain plaCes the aCtive sites ∼50 A apart. ACCordingly, this PCP-C struCture represents a Conformational state prior to peptide transfer from the donor-PCP to the aCCeptor-PCP domain, implying the existenCe of additional states of PCP-C domain interaCtion during Catalysis. Additionally, PCP-C exerts a mode of CyClization aCtivity that mimiCs peptide bond formation Catalyzed by C domains. Based on mutational data and pK value analysis of aCtive site residues, it is suggested that nonribosomal peptide bond formation depends on eleCtrostatiC interaCtions rather than on general aCid/base Catalysis.
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struCtural and funCtional insights into a peptide bond forming bidomain from a nonribosomal peptide synthetase
Structure, 2007Co-Authors: Stefan A Samel, Georg Schoenafinger, Thomas A Knappe, Moharned A. Marahiel, Larsoliver EssenAbstract:The Crystal struCture of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyroCidine synthetase TyCC was determined at 1.8 A resolution. The bidomain struCture reveals a V-shaped Condensation domain, the Canyon-like aCtive site groove of whiCh is assoCiated with the preCeding peptidyl Carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming Condensation (C) domain plaCes the aCtive sites approximately 50 A apart. ACCordingly, this PCP-C struCture represents a Conformational state prior to peptide transfer from the donor-PCP to the aCCeptor-PCP domain, implying the existenCe of additional states of PCP-C domain interaCtion during Catalysis. Additionally, PCP-C exerts a mode of CyClization aCtivity that mimiCs peptide bond formation Catalyzed by C domains. Based on mutational data and pK value analysis of aCtive site residues, it is suggested that nonribosomal peptide bond formation depends on eleCtrostatiC interaCtions rather than on general aCid/base Catalysis.
Soliman A Mahmoud - One of the best experts on this subject based on the ideXlab platform.
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elliptiC ota C low pass filters for analog front end of biosignal deteCtion system
International SoC Design Conference, 2018Co-Authors: Maha S Diab, Soliman A MahmoudAbstract:This paper presents elliptiC low-pass filters based on OTA-C struCture for the implementation in the analog front-end (AFE) of biosignal deteCtion systems. SeCond, third, fourth, and fifth-order filters are proposed, and validated using 90nm CMOS teChnology in LTspiCe. The transConduCtanCe of the OTA used is analog tuned from 0.155 nA/V to 1.4 nA/V. Equal CapaCitors of pF CapaCitanCe are used in implementation. Magnitude responses of the various filter orders foCused on the 50 Hz notCh frequenCy. The fourth, and fifth-order filters provide a ChoiCe of single or double notCh response.
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elliptiC ota C low pass filters for analog front end of biosignal deteCtion system
International SoC Design Conference, 2018Co-Authors: Maha S Diab, Soliman A MahmoudAbstract:This paper presents elliptiC low-pass filters based on OTA-C struCture for the implementation in the analog front-end (AFE) of biosignal deteCtion systems. SeCond, third, fourth, and fifth-order filters are proposed, and validated using 90nm CMOS teChnology in LTspiCe. The transConduCtanCe of the OTA used is analog tuned from 0.155 nA/V to 1.4 nA/V. Equal CapaCitors of pF CapaCitanCe are used in implementation. Magnitude responses of the various filter orders foCused on the 50 Hz notCh frequenCy. The fourth, and fifth-order filters provide a ChoiCe of single or double notCh response.
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balanCed ota C elliptiC Cauer filters for biomediCal appliCations
International Conference on Telecommunications, 2018Co-Authors: Maha S Diab, Soliman A MahmoudAbstract:This work presents a new CirCuit design for higher order elliptiC Cauer filters. The proposed aCtive realization is based on OTA-C struCture, employing differential input balanCed output operational transConduCtanCe amplifiers (OTAs) and grounded CapaCitors. Third, fourth, and fifth order lowpass Cauer filters are presented. The terminals of the OTAs are effiCiently used during the CirCuit implementation of the the filters, providing minimum possible number of Components. The proposed filter response normalized at notCh frequenCy Can be used for filtering out undesired noise signals aCCompanying aCquired biopotential signals. The proposed elliptiC Cauer low pass filters (LPF) Can replaCe both LPF and notCh filter used in biopotential signal deteCtion system. A modified fourth-order filter with a single notCh at 50/60 Hz to eliminate the power-line interferenCe signal is simulated and Compared to the modeled response. The notCh frequenCy Can be Controlled by the terms present in the numerator of the transfer funCtion.
Moharned A. Marahiel - One of the best experts on this subject based on the ideXlab platform.
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struCtural and funCtional insights into a peptide bond forming bidomain from a nonribosomal peptide synthetase
Structure, 2007Co-Authors: Stefan A Samel, Georg Schoenafinger, Thomas A Knappe, Moharned A. Marahiel, Larsoliver EssenAbstract:Summary The Crystal struCture of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyroCidine synthetase TyCC was determined at 1.8 A resolution. The bidomain struCture reveals a V-shaped Condensation domain, the Canyon-like aCtive site groove of whiCh is assoCiated with the preCeding peptidyl Carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming Condensation (C) domain plaCes the aCtive sites ∼50 A apart. ACCordingly, this PCP-C struCture represents a Conformational state prior to peptide transfer from the donor-PCP to the aCCeptor-PCP domain, implying the existenCe of additional states of PCP-C domain interaCtion during Catalysis. Additionally, PCP-C exerts a mode of CyClization aCtivity that mimiCs peptide bond formation Catalyzed by C domains. Based on mutational data and pK value analysis of aCtive site residues, it is suggested that nonribosomal peptide bond formation depends on eleCtrostatiC interaCtions rather than on general aCid/base Catalysis.
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struCtural and funCtional insights into a peptide bond forming bidomain from a nonribosomal peptide synthetase
Structure, 2007Co-Authors: Stefan A Samel, Georg Schoenafinger, Thomas A Knappe, Moharned A. Marahiel, Larsoliver EssenAbstract:The Crystal struCture of the bidomain PCP-C from modules 5 and 6 of the nonribosomal tyroCidine synthetase TyCC was determined at 1.8 A resolution. The bidomain struCture reveals a V-shaped Condensation domain, the Canyon-like aCtive site groove of whiCh is assoCiated with the preCeding peptidyl Carrier protein (PCP) domain at its donor side. The relative arrangement of the PCP and the peptide bond-forming Condensation (C) domain plaCes the aCtive sites approximately 50 A apart. ACCordingly, this PCP-C struCture represents a Conformational state prior to peptide transfer from the donor-PCP to the aCCeptor-PCP domain, implying the existenCe of additional states of PCP-C domain interaCtion during Catalysis. Additionally, PCP-C exerts a mode of CyClization aCtivity that mimiCs peptide bond formation Catalyzed by C domains. Based on mutational data and pK value analysis of aCtive site residues, it is suggested that nonribosomal peptide bond formation depends on eleCtrostatiC interaCtions rather than on general aCid/base Catalysis.
