1,2-Dithia-5,8,11,14-tetraoxacyclohexadecane and 1,2-dithia-5,8,11,17-pentaoxacyclononadecane: ‘switched-on’ crown ethers

Raban, Morton; Greenblatt, Jeremy; Kandil, Farouk

doi:10.1039/c39830001409

Cited by 21 publications

(4 citation statements)

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“…The cubic term of eq. [2] represents an anharmonic modification of the Hooke's law function. As suggested by Allinger, the value of Ki has been set at 2.0mdyn/A (5).…”

Section: Atom Types Of Mmpepmentioning

confidence: 99%

“…This correction may be approximated with the cubic term of a truncated Taylor series expansion (eq. [2]), in which lo is an ideal bond length, 1 is the bond length of interest, and K I and KI are stretching force constants.…”

Section: Atom Types Of Mmpepmentioning

confidence: 99%

“…In eqs. [2]- [6], E l represents bond length energies, E2 bond angle energies, Eg dihedral angle energies, E4 van der Waals interactions, and E5, electrostatic interactions. All variables and constants are defined in subsequent discussions.…”

Section: The Mmpep Force Fieldmentioning

confidence: 99%

“…In the course of an investigation into the interaction of the anticonvulsant drug 53-diphenylhydantoin (DPH) with its receptor (I), it became necessary to study some properties of a hexapeptide containing two terminal cysteines (2). The four internal amino acids of this peptide had to be selected in such a manner that, in its oxidized cyclic form (I), the compound…”

Section: Introductionmentioning

confidence: 99%

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MMPEP: Development and evaluation of peptide parameters for Allinger's MMP2(85) programme, including calculations on crambin and insulin

Wolfe¹,

Weaver²,

Yang³

1988

Can. J. Chem.

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SAUL WOLFE, DONALD FREDRIC WEAVER, and KIYULL YANG. Can. J. Chem. 66, 2687Chem. 66, (1988. Allinger's MMP2(85) program has been converted to an IBM environment, and the dimensions expanded to a current maximum of 999 atoms. Substantial additional expansion will be possible. An all-atom set of parameters, which permit Allinger's comprehensive force field to be applied to the molecular mechanics treatment of peptides, has been determined. These parameters, termed MMPEP, contain 21 atom types: 5 for carbon, 6 for hydrogen, 5 for nitrogen, 4 for oxygen, and 1 for sulfur, and are based on crystallographic heavy atom bond lengths and bond angles, vibrational and microwave spectra, and ab initio calculations. To minimize the conformational energy of a peptide from an initial starting geometry, all internally stored parameters are released, and replaced by PEPCON, a 360-line external file containing the MMPEP parameters.The ability of the MMPEP parameterization of MM85 to reproduce experimental crystal structures has been tested on several peptides and polypeptides, and the use of a dielectric constant E = 78.5 D leads to the following results: Ala-Ala-Gly (rms = 0.261); Gly-Gly-Val (rms = 0.349); glutathione (rms = 0.417); crambin (327 heavy atoms; rms = 0.310 for all heavy atoms); insulin (389 heavy atoms; rms = 0.646 for all heavy atoms); the origins of deviations can be interpreted. No problems have been encountered in the application of the Newton-Raphson minimization procedure to such large molecules as crambin and insulin, even though all possible nonbonded interactions have been retained. On the IBM 3081 computer, real time minimization of tripeptides requires 1-2 min, crambin requires 250 min, and insulin 200 min. Since hydrogen bonding in Allinger's force field is a natural result of electrostatic and van der Waals interactions, in MMPEP hydrogen bonding is taken into account through the large number of hydrogen atom types and their different bond moments and van der Waals radii. Afin de vkrifier les possibilites du programme MM85 incorporant les paramttres MMPEP de reproduire les structures cristallines expkrimentales, on a utilisk plusieurs peptides et polypeptides; utilisant une constante diklectrique E = 78,5 D, on obtient les rksultats suivants : Ala-Ala-Gly (rms = 0,261); Gly-Gly-Val (rms = 0,349); glutathion (rms = 0,417); crambine (327 atomes lourds; rms = 0,3 10 pour tous les atomes lourds); insuline (389 atomes lourds; rms = 0,646 pour les atomes lourds); on peut interpriter les causes des dbviations. On n'a pas rencontrC de problemes dans I'application de la mkthode de minimisation de Newton-Raphson a des molkcules de la taille de la crambine et l'insuline, m&me si toutes les interactions non-likes ont kt6 conservkes. Sur un ordinateur IBM 3081, le temps rkel de minimisation des tripeptides est de 1 a 2 min; celui de la crambine est de 250 min et celui de l'insuline est de 200 min. Dans le champ de force d'Allinger, les liaisons hydrogtnes sont un rksultat nature1 des interactions klectrostatiques...

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“…The cubic term of eq. [2] represents an anharmonic modification of the Hooke's law function. As suggested by Allinger, the value of Ki has been set at 2.0mdyn/A (5).…”

Section: Atom Types Of Mmpepmentioning

confidence: 99%

Section: Atom Types Of Mmpepmentioning

confidence: 99%

Section: The Mmpep Force Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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MMPEP: Development and evaluation of peptide parameters for Allinger's MMP2(85) programme, including calculations on crambin and insulin

Wolfe¹,

Weaver²,

Yang³

1988

Can. J. Chem.

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Alkali Metal Cation Selectivity of an Oligo-Ether Substituted Norbornadiene and Quadricyclane Isomer

Herges

Winkler

2001

Eur. J. Org. Chem.

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We present investigations aimed at using the norbornadiene/ quadricyclane system as a framework for a switchable cation carrier. According to molecular modelling studies a suitably substituted system should perform a pincer-like motion upon isomerisation and reisomerisation, while complexing and decomplexing a host molecule. To this end, we investigated the complexing abilities of a 1,5,6,7-tetrasubstituted quadricyclane polyether and its corresponding norbornadiene isomer. The picrate extraction method was applied to determine the extraction constants K ex and the association constants K ass of these polyethers with alkali metal cations in chloro- [a]

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ChemInform Abstract: 1,2‐DITHIA‐5,8,11,14‐TETRAOXACYCLOHEXADECANE AND 1,2‐DITHIA‐5,8,11,14,17‐PENTAOXACYCLONONADECANE: SWITCHED‐ON CROWN ETHERS

Raban¹,

Greenblatt²,

Kandil³

1984

Chemischer Informationsdienst

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1,2-Dithia-5,8,11,14-tetraoxacyclohexadecane and 1,2-dithia-5,8,11,17-pentaoxacyclononadecane: ‘switched-on’ crown ethers

Cited by 21 publications

References 0 publications

MMPEP: Development and evaluation of peptide parameters for Allinger's MMP2(85) programme, including calculations on crambin and insulin

MMPEP: Development and evaluation of peptide parameters for Allinger's MMP2(85) programme, including calculations on crambin and insulin

Alkali Metal Cation Selectivity of an Oligo-Ether Substituted Norbornadiene and Quadricyclane Isomer

ChemInform Abstract: 1,2‐DITHIA‐5,8,11,14‐TETRAOXACYCLOHEXADECANE AND 1,2‐DITHIA‐5,8,11,14,17‐PENTAOXACYCLONONADECANE: SWITCHED‐ON CROWN ETHERS

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