<i>Conformational Properties of Macromolecules</i>

Hopfinger, A. J.; Bovey, F. A.

doi:10.1063/1.3128549

Cited by 58 publications

(85 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Buckingham's pairwise atom-atom interaction functions have been used: (Hopfinger, 1973). where Ui, corresponds to the energy barrier in the eclipsed conformation during the rotation of the angle, and qiS is the torsional angle.…”

Section: Introductionmentioning

confidence: 99%

Conformation and mode of organization of amphiphilic membrane components: a conformational analysis

Brasseur¹,

Ruysschaert²

1986

Biochemical Journal

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Conformation and mode of organization of amphiphilic membrane components: a conformational analysis

Brasseur¹,

Ruysschaert²

1986

Biochemical Journal

View full text Add to dashboard Cite

“…For this purpose we have calculated the entropy energy term relative to the two energy minima for the 2,2'-dichloro derivative according to ref. 16. The value 0.42 kcal/niol at 25 OC obtained for TAS gives AG = 1.53 kcal/mol which does not cause appreciable changes in thc equilibrium position already evaluated from the AH value.…”

Section: Di-s~ibs~it~ited Beilzol~hetzotzesmentioning

confidence: 67%

Molecular conformations of ortho-substituted benzophenones

Zuccarello¹,

Millefiori²,

Trovato³

1976

Can. J. Chem.

View full text Add to dashboard Cite

The minimum energy conformations of some mono- and di-substituted benzophenones were determined from contour maps of potential energy calculated by a semiempirical approach. The electrostatic interactions play a relevant role in the relative stabilities when different minima are possible. Comparison with the available experimental data reveals a good agreement with geometrical data, and a poorer agreement with energies in highly strained conformations.

show abstract

“…The conformations yielding the lowest internal energy were eventually submitted to the energy function minimization procedure (22) in a medium of low dielectric constant representative of the hydrophobic part of the membrane or at the simulated lipid-water interface (20)(21). The values used for the valence angles, boundary lengths, atomic charges, torsional potentials, and energy values for the estimation of Van der Waals interactions are those currently used in conformational analysis (21,(23)(24)(25)(26). Calculations were made on a CDC-Cyber 170 coupled to a Calcomp 1051 drawing table using the PLUTO drawing program (27).…”

Section: Methodsmentioning

confidence: 99%

Conformational analysis of 6-cis- and 6-trans-leukotriene B4-calcium complexes.

Brasseur¹,

Deleers²

1984

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

We present a computational description of the conformation of a pair of two isomeric molecules (6-cisand 6-trans-leukotriene B4) forming a complex with one calcium ion. Our theoretical prediction of the membrane-water interface conformation and of the bulk lipid phase conformation of the two different isomeric complexes are in excellent agreement with experimental data on the leukotriene-mediated calcium lonophoresis in liposomes. The two isomers lead to vastly different conformations in the presence of Ca2 , and the most probable conformation of the permeant species shows a globular conformation able to cross a lipid membrane.A number of membrane lipids contain in position 2 esterified arachidonic acid, which when released is the precursor of important signal molecules including, among others, leukotrienes. After stimulation of secretory cells, the turnover of membrane phospholipids and the breakdown of phosphatidyl inositol lead to the formation of phosphatidic acid and the release and oxygenation of arachidonic acid. The socalled "phosphatidyl inositol" response is accompanied by an enhancement of calcium flux (1-5). The ionophoretic capacity of phosphatidic acid and other anionic phospholipids (6) and of prostaglandins (7,8) has already been tested in Pressman cells (9, 10). It was suggested that they act as calcium ionophores in membranes. The calcium ionophoresis by lipid soluble plasma membrane extracts of secretory cells has also been described in both the Pressman cell (11) and in liposomes (12). Recently, several cyclooxygenase and lipoxygenase products have been examined for their calcium ionophoretic properties in liposome membranes (13)(14)(15). It has been clearly demonstrated that 6-cis-leukotriene B4, unlike 6-trans-leukotriene B4 and cyclooxygenase products, is able to act as a calcium ionophore (14-15).To obtain information on the ionophoretic behavior of these agents at the model membrane level, we have studied the conformation of two molecules of (5S,12R)-dihydroxy-6-cis,8,10-trans,14-cis-icosatetraenoic acid bound to one calcium [(6-cisLTB4)2-Ca] and of two molecules of (5S,12R)-dihydroxy-6,8,1O-trans,14-cis-icosatetraenoic acid (16) bound to one calcium ion [(6-trans-LTB4)2-Ca] at a simulated lipidwater interface and in hydrophobic medium. We have analyzed complexes with a 2:1 stoichiometry, because monocarboxylic ionophores such as A23187 have this stoichiometry (10,17). METHODSThe method used for the theoretical conformational analysis of the two different Ca complexes is based on a semi-empirical method described elsewhere (18)(19)(20)(21). Briefly, the total conformational energy that represents the sum of the contributions resulting from the Van der Waals interactions, the torsional potential, and the electrostatic interactions is calculated for a large number of conformations in a systematic analysis bearing on all angles. The conformations yielding the lowest internal energy were eventually submitted to the energy function minimization procedure (22) in a medium of low dielec...

show abstract

Conformational Properties of Macromolecules

Cited by 58 publications

References 0 publications

Conformation and mode of organization of amphiphilic membrane components: a conformational analysis

Conformation and mode of organization of amphiphilic membrane components: a conformational analysis

Molecular conformations of ortho-substituted benzophenones

Conformational analysis of 6-cis- and 6-trans-leukotriene B4-calcium complexes.

Contact Info

Product

Resources

About