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Biomedical subjects

L C Andrews

Publications and source records attributed to L C Andrews.

7 recordsLinked to original sources
PubMed1994

The Fourier-Green's function and the rapid evaluation of molecular potentials.

Two tasks must be accomplished when calculating the binding modalities and binding energies of two molecules in solution: the calculation of the interaction energy and the calculation of the effects of solvation. It is the competition between the energy of binding and the energy of remaining solvation which determines the binding properties. It is necessary to calculate (or at least approximate in some manner) the partition function in order to make a theoretical estimate of these effects. An efficient algorithm for performing the energy evaluations necessary for this calculation is presented in this paper. The fast Fourier transform (FFT) is used in combination with a polar factorization of the potentials to calculate the interaction energy at all relative translations between two molecules of fixed orientation. Thermodynamic quantities, including the partition function, internal and free energies can then be estimated from a set of these calculations covering the orientation space.

Algorithms↗
PubMed1992

Crystal structure at 1.5-A resolution of d(CGCICICG), an octanucleotide containing inosine, and its comparison with d(CGCG) and d(CGCGCG) structures.

The octadeoxyribonucleotide d(CGCICICG) has been crystallized in space group P(6)5(22) with unit cell dimensions of a = b = 31.0 A and c = 43.7 A, and X-ray diffraction data have been collected to 1.5-A resolution. Precession photographs and the self-Patterson function indicate that 12 base pairs of Z-conformation DNA stack along the c-axis, and the double helices pack in a hexagonal array similar to that seen in other crystals of Z-DNA. The structure has been solved by both Patterson deconvolution and molecular replacement methods and refined in space group P(6)5 to an R factor of 0.225 using 2503 unique reflections greater than 3.0 sigma (F). Comparison of the molecules within the hexagonal lattice with highly refined crystal structures of other Z-DNA reveals only minor conformational differences, most notably in the pucker of the deoxyribose of the purine residues. The DNA has multiple occupancy of C:I and C:G base pairs, and C:I base pairs adopt a conformation similar to that of C:G base pairs.

Base Composition↗
PubMed1991

Modeling conformational change in macromolecules as an elastic deformation.

Macromolecules are elastic bodies. Atomic structures are available for nucleic acids and proteins in two or more different conformations. It is a common practice to compare two structures by finding the best rigid body superposition of the molecules. This ignores possible deformations. There is useful information in the deviations from the rigid body superposition. If the deviations are considered to be elastic deformations of a common structure than it is possible to extract this information. Results are shown for comparisons of deoxyhemoglobin versus carbonmonoxyhemoglobin and for two different conformations of catabolite gene activator protein.

Bacterial Proteins↗
PubMed1978

Location of amino acid residues in human deoxy hemoglobin.

A table has been compiled of the spatial disposition of the amino acid residues in the human deoxy hemoglobin tetramer. The table also indicates regions of possible contact between residues in each subunit and possible contacts between subunits.

Amino Acids↗