Distance Comparisons

Martin YC. Distance comparison (DISCO) A new strategy for examining 3D structure-activity relationships. In Hansch C, Fujita T, editors, Classical and 3D QSAR in agrochemistry. Washington, DC American Chemical Society, 1995. p.318-29. 

The inverted region in electron transfer reactions is studied for the reaction of electronically-excited ruthenium(II) tris-bipyridyl ions with various metal(III) tris-bipyridyl complexes. Numerical calculations for the diffusion-reaction equation are summarized for the case where electron transfer occurs over a range of distances. Comparison is made with the experimental data and with a simple approximation. The analysis reveals some of the factors which can cause a flattening of the In k versus AG curve in the inverted... 

Tripos. DISCO (Distance Comparisons), available as DISCOtech from Tripos, Inc., St. Louis, MO, with additional implemented functionalities www.tripos.-com. 

Partitioning. In contrast to clustering techniques, partitioning algorithms do not rely on pair-wise molecular and distance comparison and can therefore be applied to very large compound source databases. Rather than comparing molecular positions,... 

Gemperline, P.J. and Boyer, N.R., Classification of near-infrared spectra using wavelength distances comparison to the Mahalanobis distance and residual variance methods, Anal. Chem., 67, 160-166, 1995. 

Cremer and colleagues also calculated the H and C NMR chemical shifts as a function of the C(l)-C(7) distance Comparison of these calculated and observed shift values of the homotropenylium ion confirmed a C(l)-C(7) distance of 2 A. At this distance the chemical shift difference between the exo and endo C(8) protons became a maximum. In addition the calculated magnetic susceptibility adopted a maximum value, i.e., a distinct susceptibility exaltation was found for the C(l)-C(7) equilibrium distance of 2 A" ... 

Carugo O, Pongor S. Protein fold similarity estimated hy a probabilistic approach based on C(alpha)-C(alpha) distance comparison. J. Mol. Biol.. 2002 315 887-898. 

Impact power of cartridges of various m.ikes can be Jiandily tested by the simple method sliown here. A block of hard wood is placed on the edge of a box and bullets discharged into it from a uniform distance. Comparison is nlTord-cd by the varying distances the block will be thrown when clifTcrcnt shells are used. 

Distance Comparison for multiple pharmacophores generations, Based on clique detection. The conformational search is separated. 

Martin YC. Distance comparisons a new strategy for examining three-dimensional structure-activity relationships. ACS Symp Ser 1995 606 318-329. 

DISCO (Distance Comparison) was developed by Dr. Yvonne Martin and coworkers at Abbott Laboratories and distributed by Tripos Associates, St. Louis, MO. 2000. 

Gemperline, P.J. Boyer, N.R. (1995). Classification of near-infrared spectra using wavelength distances Comparisons to the Mahalanobis distance and Residual Variance methods. Analytical Chemistry. Vol.67, pp. 160-166. ISSN 0003-2700 Gonzalez, A.G. (2007). Use and misuse of supervised pattern recognition methods for interpreting compositional data. Journal of Chromatograpy A. Vol. 1158, pp. 215-225. ISSN 0021-9673... 

Finally, the geometric constraints that must be met are specified. The constraints are the acceptable ranges of distances, angles, torsional angles, and plane angles. Distance constraints may be specified between points, between a point and a line, or between a point and a plane. Also, at one point in the distance comparison, one may specify any atom of the molecule to allow for primitive bump checking. Thus, the geometric search is deliberately flexible. 

Finally, the discussion of 3D MCS algorithms is closely related to the emerging technique of pharmacophore mapping, which seeks to provide automated tools for the identification and subsequent representation of pharmacophore models for sets of biologically related compounds, that is, the 3D chemical and spatial requirements for bioactivity (as reviewed by Bures et al.). 2 An example of work in this area is the DISCO (Distance Comparisons) program that has been developed by Martin et al.203 DISCO identifies the maximum overlap (to within allowed interatomic distance tolerances) between a set of structures, which can be either a set of different molecules or a set different... 

Grindley, H.M. 3-D Distance Comparisons in Protein Secondary Structure Motifs For Substructure Search Refinement . M.Sc. dissertation. University of Sheffield, 1988. 

Proximity between Pairs of Objects. A number of tasks involve finding a pair of items that are close together - but location in the workspace is not important - such as locating a 3-star hotel that is close to a railway station. To complete this task, the user must locate all pairs of items in the workspace, perform distance comparisons to determine which candidate pair are closest together (or below some close enough threshold), and remember the best pair. 

Figure 3 Structural alignments with discrete properties. Methods are based on discrete properties using the DG algorithm (1) or clique-detection (11) as implemented in distance comparisons (DISCO), and Apex-3D. The structure representation, based on discrete properties, resorts to one atomic descriptor (I), usually the atom type, or multiple atomic or site descriptors (II). In the first method (I), the conformational analysis is restricted to the generation of molecular geometries which allow a common arrangement of selected phaimacophoric moieties present in a rigid compound used as template. In the second method (II), the conformational analysis procedure may involve a systematic enumeration of all the possible conformadons for each ligand. The search similarity is directed towards the confirmation of a predefined pharmacophore postulated by the modeler or from some classical SAR in the case of the active analog approach (1), or the automated identification of pharmacophores and bioacdve conformations (II)...

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