CAMSEQ Conformational Analysis

N. Conformational Analysis of Molecules in Solution (CAMSEQ). A problem of long standing in chemistry has been to estimate the relationship between the conformation of a molecule in the crystal, as measured by X-ray methods, with that in solution where barriers to rotation are greatly reduced. A sophisticated program set for Conformational Analysis of Molecules in Solution by Empirical and Quantum-mechanical methods (CAMSEQ) has been developed for this purpose by Hopfinger and co-workers [l2] at Case Western Reserve University. 

CAMSEQ/M A Microprocessor-Based Conformational Analysis System... 

Conformational analysis is becoming a widely utilized tool in drug design, molecular modeling, and the determination of structure-activity relationships. Of the many techniques presently available for conformational studies, classical, empirical potential energy functions hold great promise in providing relatively inexpensive explorations of conformational hyperspace in various simulated solvent environments. An excellent example of the application of these classical techniques is embodied in the CAMSEQ Software System (1,2.,3.). 

A total of 50 options are available. The advantage of having total compatibility with the batch CAMSEQ is that CAMSEQ/M may be used either as a "stand-alone" conformational analysis device, or it may be used as an interactive, conversational, off-line input device for batch CAMSEQ. Since an available host computer would probably perform the calculations more rapidly than the Tektronix microcomputer, this provides an easy to use batch program interface when results are needed "immediately". 

Based on the options specified, CAMSEQ/M may request additional information regarding the energy parameters to use, the solvent environments to be simulated, and other pertinent information regarding the conformational analysis to be performed. The user is then given the opportunity to assemble a batch CAMSEQ data set to be sent to an alternate computer. This feature assembles all data accumulated into the form of a CAMSEQ run deck and saves the information on a disk file. Alternatively, CAMSEQ/M begins the conformational analysis task, saving rotational and energy information on a disk file. 

Current efforts in the development of the CAMSEQ/M system include the interfacing of a low-cost microcomputer to the 4051 to handle the actual conformational search and energy calculation. This would free the graphics terminal for other general purpose computing tasks including the set-up of additional molecules for conformational study. Conceptually, banks of these low-cost microcomputers could be linked to a single 4051 to provide a very efficient conformational analysis device. 

Hopfinger and Battershell developed a semiempirical program, CAMSEQ, with the aim of attempting to make a solvent-dependent conformational analysis and calculating logP values on a whole-molecule basis. For simplicity of calculation, methanol was chosen as a model solvent, and it... 

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