PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 1255498

A simple jig for building complex molecular models.

S P Heathman·J D Nicholas·P A Timmins·J L Finney
View original source ↗Export metadata ↓

Abstract

The source did not provide an abstract. Follow the original record for more information.

Explore related subjects

Models, MolecularModels, StructuralJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S P Heathman, J D Nicholas, P A Timmins, J L Finney. 1976. A simple jig for building complex molecular models.. https://doi.org/10.1088/0022-3735%2F9%2F2%2F025

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1992

Structure of bis(4-chlorophenolato)[hydrotris(3,5-dimethyl-1- pyrazolyl)borato]oxomolybdenum(V).

[Mo(C15H22BN6)(C6H4ClO)2O], M(r) = 664.24, triclinic, P1, a = 10.585 (2), b = 12.068 (3), c = 13.728 (3) A, alpha = 88.01, beta = 69.94, gamma = 65.78 degrees, V = 1490.8 A3, Z = 2, Dx = 1.48 g cm-3, Mo K alpha, lambda = 0.71073 A, mu = 6.5 cm-1, F(000) = 678, T = 296 (1) K, R = 0.034, wR = 0.049 for 4634 observed independent reflections with F2 greater than 3 sigma (F2). This is the second structurally characterized mononuclear monooxo transition-metal complex containing the phenolato ligand. The molecule exhibits a distorted octahedral coordination geometry, and the Mo atom is ligated by a terminal O atom, two p-chloro-substituted phenolato groups, and a tridentate facially coordinated hydrotris(3,5-dimethylpyrazolyl)borate ligand (L).

Models, Molecular↗
PubMed1992

Characterization at atomic resolution of peptide helical structures.

A survey of literature for the various types of helices experimentally observed in high-resolution single crystal x-ray diffraction analyses of peptides has allowed to determine accurate conformational and helical parameters for the various secondary structures such as the alpha-helix, the 3(10)-helix, the fully extended conformation (2(5)-helix) and the beta-bend ribbon spiral. For each of these structures the characteristic phi, psi conformational parameters, n, the number of residues per turn, h, the height per residues and p, the pitch of the helix are described.

Models, Molecular↗
PubMed1992

Variable ranges of interactions in polypeptide conformations with a method to complement molecular modeling.

Formulations of conformational weights for helix-coil transitions can be extended to substantially more complex situations than are usually pursued. General rules for matrix multiplication that depend parametrically on the interaction ranges and numbers of rotamers of residues are presented. The orders of the matrices of statistical weights can be increased with chain length, so that an individual matrix element can represent any specified single conformation, as needed. By the appropriate choice of interaction ranges and numbers of available conformers, approximations can be introduced in which: (1) an average of the conformations of any chain segment is obtained, (2) specific residue-residue interactions are excluded, or (3) the conformation of a part of the chain is restricted or fixed. The method is appropriate for treating specific interactions in peptides and could be used together with available experimental information to develop models of conformational transitions. As such, the methods represent a class of calculations aimed at more rigorous calculations built around known features of a molecule. The aim is to facilitate calculations that bridge the gap between nonquantitative molecular model building and more rigorous but less directed molecular mechanics calculations. The method can directly include any desired longer range of interactions, if the interaction range is not too long to make impossible the manipulation of the requisite matrices. An outline is presented of an application to treat salt bridges in the C peptide of ribonuclease A.

Models, Molecular↗