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Peter Comba - One of the best experts on this subject based on the ideXlab platform.

  • synthesis And cuii coordinAtion chemistry of A PAtellAmide derivAtive consequences of the chAnge from the nAturAl thiAzole oxAzoline to the ArtificiAl imidAzole heterocycles
    Inorganic Chemistry, 2011
    Co-Authors: Peter Comba, Nina Dovalil, Graeme R Hanson, Gerald Linti
    Abstract:

    The synthesis And CuII coordinAtion chemistry of the cyclic pseudo-octApeptide H4pAt1, A dimethyl-imidAzole AnAlogue of nAturAlly occurring cyclic peptides (PAtellAmide A–F, AscidiAcyclAmide) is reported. Substitution of the oxAzoline And thiAzole heterocycles by dimethyl-imidAzoles leAds to A slightly different structure of the mAcrocycle in the solid stAte. The CuII coordinAtion chemistry of H4pAt1, monitored with high-resolution electrosprAy mAss spectrometry, spectrophotometric titrAtions, And EPR spectroscopy, reveAled the presence of both mono- And dinucleAr CuII complexes. The dimethyl-imidAzole AnAlogue shows A high cooperAtivity in CuII coordinAtion, thAt is, the preferred formAtion of dinucleAr complexes. The dinucleAr unbridged CuII complexes of H4pAt1 hAve unusuAl EPR feAtures, reminiscent of those of PAtellAmide D: the dipole–dipole interAction of the CuII centers is negligible due to the “mAgic Angle” orientAtion of the two CuII ions. Density functionAl theory cAlculAtions (DFT) Are used to ...

  • synthesis And structurAl properties of PAtellAmide A derivAtives And their copper ii compounds
    Chemistry: A European Journal, 2002
    Co-Authors: Paul V Bernhardt, Peter Comba, Graeme R Hanson, David P Fairlie, Lawrence R Gahan, Lutz Lotzbeyer
    Abstract:

    The synthesis, chArActerizAtion And copper(II) coordinAtion chemistry of three new cyclic peptide ligAnds, PAtJ(1) (cyclo-(Ile-Thr-(Gly)Thz-Ile-Thr-(Gly)Thz)), PAtJ(2) (cyclo-(Ile-Thr-(Gly)Thz-(D)-Ile-Thr-(Gly)Thz)), And PAtL (cyclo-(Ile-Ser-(Gly)Thz-Ile-Ser-(Gly)Thz)) Are reported. All of these cyclic peptides And PAtN (cyclo-(Ile-Ser-(Gly)Thz-Ile-Thr-(Gly)Thz)) Are derivAtives of PAtellAmide A And hAve A [24]AzAcrown-8 mAcrocyclic structure. All four synthetic cyclic peptides hAve two thiAzole rings but, in contrAst to PAtellAmide A, no oxAzoline rings. The moleculAr structure of PAtJ(1), determined by X-rAy crystAllogrAphy, hAs A sAddle conformAtion with two close-to-copArAllel thiAzole rings, very similAr to the geometry of PAtellAmide D. The two coordinAtion sites of PAtJ(1) with thiAzole-N And Amide-N donors Are eAch well preorgAnized for trAnsition metAl ion binding. The coordinAtion of copper(II) wAs monitored by UV/Vis spectroscopy, And this reveAls vArious (metA)stAble mono- And dinucleAr copper(II) complexes whose stoichiometry wAs confirmed by mAss spectrA. Two types of dinucleAr copper(II) complexes, [Cu(2)(H(4)L)(OH(2))(n)](2+) (n=6, 8) And [Cu(2)(H(2)L)(OH(2))(n)] (n=4, 6; L=PAtN, PAtL, PAtJ(1), PAtJ(2)) hAve been identified And AnAlyzed structurAlly by EPR spectroscopy And A combinAtion of spectrA simulAtions And moleculAr mechAnics cAlculAtions (MM-EPR). The four structures Are similAr to eAch other And hAve A sAddle conformAtion, thAt is, derived from the crystAl structure of PAtJ(1) by A twist of the two thiozole rings. The smAll but significAnt structurAl differences Are chArActerized by the EPR simulAtions.

Graeme R Hanson - One of the best experts on this subject based on the ideXlab platform.

  • synthesis And cuii coordinAtion chemistry of A PAtellAmide derivAtive consequences of the chAnge from the nAturAl thiAzole oxAzoline to the ArtificiAl imidAzole heterocycles
    Inorganic Chemistry, 2011
    Co-Authors: Peter Comba, Nina Dovalil, Graeme R Hanson, Gerald Linti
    Abstract:

    The synthesis And CuII coordinAtion chemistry of the cyclic pseudo-octApeptide H4pAt1, A dimethyl-imidAzole AnAlogue of nAturAlly occurring cyclic peptides (PAtellAmide A–F, AscidiAcyclAmide) is reported. Substitution of the oxAzoline And thiAzole heterocycles by dimethyl-imidAzoles leAds to A slightly different structure of the mAcrocycle in the solid stAte. The CuII coordinAtion chemistry of H4pAt1, monitored with high-resolution electrosprAy mAss spectrometry, spectrophotometric titrAtions, And EPR spectroscopy, reveAled the presence of both mono- And dinucleAr CuII complexes. The dimethyl-imidAzole AnAlogue shows A high cooperAtivity in CuII coordinAtion, thAt is, the preferred formAtion of dinucleAr complexes. The dinucleAr unbridged CuII complexes of H4pAt1 hAve unusuAl EPR feAtures, reminiscent of those of PAtellAmide D: the dipole–dipole interAction of the CuII centers is negligible due to the “mAgic Angle” orientAtion of the two CuII ions. Density functionAl theory cAlculAtions (DFT) Are used to ...

  • synthesis And structurAl properties of PAtellAmide A derivAtives And their copper ii compounds
    Chemistry: A European Journal, 2002
    Co-Authors: Paul V Bernhardt, Peter Comba, Graeme R Hanson, David P Fairlie, Lawrence R Gahan, Lutz Lotzbeyer
    Abstract:

    The synthesis, chArActerizAtion And copper(II) coordinAtion chemistry of three new cyclic peptide ligAnds, PAtJ(1) (cyclo-(Ile-Thr-(Gly)Thz-Ile-Thr-(Gly)Thz)), PAtJ(2) (cyclo-(Ile-Thr-(Gly)Thz-(D)-Ile-Thr-(Gly)Thz)), And PAtL (cyclo-(Ile-Ser-(Gly)Thz-Ile-Ser-(Gly)Thz)) Are reported. All of these cyclic peptides And PAtN (cyclo-(Ile-Ser-(Gly)Thz-Ile-Thr-(Gly)Thz)) Are derivAtives of PAtellAmide A And hAve A [24]AzAcrown-8 mAcrocyclic structure. All four synthetic cyclic peptides hAve two thiAzole rings but, in contrAst to PAtellAmide A, no oxAzoline rings. The moleculAr structure of PAtJ(1), determined by X-rAy crystAllogrAphy, hAs A sAddle conformAtion with two close-to-copArAllel thiAzole rings, very similAr to the geometry of PAtellAmide D. The two coordinAtion sites of PAtJ(1) with thiAzole-N And Amide-N donors Are eAch well preorgAnized for trAnsition metAl ion binding. The coordinAtion of copper(II) wAs monitored by UV/Vis spectroscopy, And this reveAls vArious (metA)stAble mono- And dinucleAr copper(II) complexes whose stoichiometry wAs confirmed by mAss spectrA. Two types of dinucleAr copper(II) complexes, [Cu(2)(H(4)L)(OH(2))(n)](2+) (n=6, 8) And [Cu(2)(H(2)L)(OH(2))(n)] (n=4, 6; L=PAtN, PAtL, PAtJ(1), PAtJ(2)) hAve been identified And AnAlyzed structurAlly by EPR spectroscopy And A combinAtion of spectrA simulAtions And moleculAr mechAnics cAlculAtions (MM-EPR). The four structures Are similAr to eAch other And hAve A sAddle conformAtion, thAt is, derived from the crystAl structure of PAtJ(1) by A twist of the two thiozole rings. The smAll but significAnt structurAl differences Are chArActerized by the EPR simulAtions.

Lutz Lotzbeyer - One of the best experts on this subject based on the ideXlab platform.

  • synthesis And structurAl properties of PAtellAmide A derivAtives And their copper ii compounds
    Chemistry: A European Journal, 2002
    Co-Authors: Paul V Bernhardt, Peter Comba, Graeme R Hanson, David P Fairlie, Lawrence R Gahan, Lutz Lotzbeyer
    Abstract:

    The synthesis, chArActerizAtion And copper(II) coordinAtion chemistry of three new cyclic peptide ligAnds, PAtJ(1) (cyclo-(Ile-Thr-(Gly)Thz-Ile-Thr-(Gly)Thz)), PAtJ(2) (cyclo-(Ile-Thr-(Gly)Thz-(D)-Ile-Thr-(Gly)Thz)), And PAtL (cyclo-(Ile-Ser-(Gly)Thz-Ile-Ser-(Gly)Thz)) Are reported. All of these cyclic peptides And PAtN (cyclo-(Ile-Ser-(Gly)Thz-Ile-Thr-(Gly)Thz)) Are derivAtives of PAtellAmide A And hAve A [24]AzAcrown-8 mAcrocyclic structure. All four synthetic cyclic peptides hAve two thiAzole rings but, in contrAst to PAtellAmide A, no oxAzoline rings. The moleculAr structure of PAtJ(1), determined by X-rAy crystAllogrAphy, hAs A sAddle conformAtion with two close-to-copArAllel thiAzole rings, very similAr to the geometry of PAtellAmide D. The two coordinAtion sites of PAtJ(1) with thiAzole-N And Amide-N donors Are eAch well preorgAnized for trAnsition metAl ion binding. The coordinAtion of copper(II) wAs monitored by UV/Vis spectroscopy, And this reveAls vArious (metA)stAble mono- And dinucleAr copper(II) complexes whose stoichiometry wAs confirmed by mAss spectrA. Two types of dinucleAr copper(II) complexes, [Cu(2)(H(4)L)(OH(2))(n)](2+) (n=6, 8) And [Cu(2)(H(2)L)(OH(2))(n)] (n=4, 6; L=PAtN, PAtL, PAtJ(1), PAtJ(2)) hAve been identified And AnAlyzed structurAlly by EPR spectroscopy And A combinAtion of spectrA simulAtions And moleculAr mechAnics cAlculAtions (MM-EPR). The four structures Are similAr to eAch other And hAve A sAddle conformAtion, thAt is, derived from the crystAl structure of PAtJ(1) by A twist of the two thiozole rings. The smAll but significAnt structurAl differences Are chArActerized by the EPR simulAtions.

Gerald Linti - One of the best experts on this subject based on the ideXlab platform.

  • synthesis And cuii coordinAtion chemistry of A PAtellAmide derivAtive consequences of the chAnge from the nAturAl thiAzole oxAzoline to the ArtificiAl imidAzole heterocycles
    Inorganic Chemistry, 2011
    Co-Authors: Peter Comba, Nina Dovalil, Graeme R Hanson, Gerald Linti
    Abstract:

    The synthesis And CuII coordinAtion chemistry of the cyclic pseudo-octApeptide H4pAt1, A dimethyl-imidAzole AnAlogue of nAturAlly occurring cyclic peptides (PAtellAmide A–F, AscidiAcyclAmide) is reported. Substitution of the oxAzoline And thiAzole heterocycles by dimethyl-imidAzoles leAds to A slightly different structure of the mAcrocycle in the solid stAte. The CuII coordinAtion chemistry of H4pAt1, monitored with high-resolution electrosprAy mAss spectrometry, spectrophotometric titrAtions, And EPR spectroscopy, reveAled the presence of both mono- And dinucleAr CuII complexes. The dimethyl-imidAzole AnAlogue shows A high cooperAtivity in CuII coordinAtion, thAt is, the preferred formAtion of dinucleAr complexes. The dinucleAr unbridged CuII complexes of H4pAt1 hAve unusuAl EPR feAtures, reminiscent of those of PAtellAmide D: the dipole–dipole interAction of the CuII centers is negligible due to the “mAgic Angle” orientAtion of the two CuII ions. Density functionAl theory cAlculAtions (DFT) Are used to ...

Paul V Bernhardt - One of the best experts on this subject based on the ideXlab platform.

  • synthesis And structurAl properties of PAtellAmide A derivAtives And their copper ii compounds
    Chemistry: A European Journal, 2002
    Co-Authors: Paul V Bernhardt, Peter Comba, Graeme R Hanson, David P Fairlie, Lawrence R Gahan, Lutz Lotzbeyer
    Abstract:

    The synthesis, chArActerizAtion And copper(II) coordinAtion chemistry of three new cyclic peptide ligAnds, PAtJ(1) (cyclo-(Ile-Thr-(Gly)Thz-Ile-Thr-(Gly)Thz)), PAtJ(2) (cyclo-(Ile-Thr-(Gly)Thz-(D)-Ile-Thr-(Gly)Thz)), And PAtL (cyclo-(Ile-Ser-(Gly)Thz-Ile-Ser-(Gly)Thz)) Are reported. All of these cyclic peptides And PAtN (cyclo-(Ile-Ser-(Gly)Thz-Ile-Thr-(Gly)Thz)) Are derivAtives of PAtellAmide A And hAve A [24]AzAcrown-8 mAcrocyclic structure. All four synthetic cyclic peptides hAve two thiAzole rings but, in contrAst to PAtellAmide A, no oxAzoline rings. The moleculAr structure of PAtJ(1), determined by X-rAy crystAllogrAphy, hAs A sAddle conformAtion with two close-to-copArAllel thiAzole rings, very similAr to the geometry of PAtellAmide D. The two coordinAtion sites of PAtJ(1) with thiAzole-N And Amide-N donors Are eAch well preorgAnized for trAnsition metAl ion binding. The coordinAtion of copper(II) wAs monitored by UV/Vis spectroscopy, And this reveAls vArious (metA)stAble mono- And dinucleAr copper(II) complexes whose stoichiometry wAs confirmed by mAss spectrA. Two types of dinucleAr copper(II) complexes, [Cu(2)(H(4)L)(OH(2))(n)](2+) (n=6, 8) And [Cu(2)(H(2)L)(OH(2))(n)] (n=4, 6; L=PAtN, PAtL, PAtJ(1), PAtJ(2)) hAve been identified And AnAlyzed structurAlly by EPR spectroscopy And A combinAtion of spectrA simulAtions And moleculAr mechAnics cAlculAtions (MM-EPR). The four structures Are similAr to eAch other And hAve A sAddle conformAtion, thAt is, derived from the crystAl structure of PAtJ(1) by A twist of the two thiozole rings. The smAll but significAnt structurAl differences Are chArActerized by the EPR simulAtions.