Computer Modeling System Research Articles

Evidence for a multiple random coupling mechanism in the alpha-ketoglutarate dehydrogenase multienzyme complex of Escherichia coli: a computer model analysis.

A computer modeling system was used to analyze experimental data for inactivation of the Escherichia coli alpha-ketoglutarate dehydrogenase complex accompanying release of lipoic acid residues by lipoamidase and by trypsin [Stepp, L. R., Bleile, D. M., McRorie, D. K., Pettit, F. H. & Reed, L. J. (1981) Biochemistry 20, 4555-4560]. The results provide insight into the active-site coupling mechanism in the alpha-ketoglutarate dehydrogenase complex. The model studies indicate that the overall activity of the alpha-ketoglutarate dehydrogenase complex is influenced by redundancies and random processes that we describe as a multiple random coupling mechanism. More than one lipoyl moiety services each E1 subunit (alpha-ketoglutarate dehydrogenase, EC 1.2.4.2), and an extensive lipoyl-lipoyl interaction network for exchange of electrons and possibly acyl groups must also be present. The best fit between computed and experimental data was obtained with a model that has two lipoyl moieties servicing each E1 subunit and a lipoyl-lipoyl interaction network that links all lipoyl moieties on the E2 cube (dihydrolipoamide succinyltransferase, EC 2.3.1.61). The single lipoyl moiety on an E2 subunit is assumed to service the coenzyme A-dependent succinyltransferase site of that E2 subunit as well as an E3 subunit (dihydrolipoamide dehydrogenase, EC 1.6.4.3) if the latter is bound to that particular E2 subunit.

A modelling framework for comparative testing of energy forecasts

A project is described in which a methodology was developed for the comparative testing of medium-term national energy forecasts. The basis of the approach is a computer modelling system which can be used flexibly to investigate the dynamics of alternative assumptions about energy futures. The application of the methodology to the forecasts produced by a particular research group is discussed and the educative value of a modelling approach for the users in this case is explained. The study is intended as a contribution to the U.K. national debate on energy policy.

Ames interactive molecular model building system: A 3-D computer modelling system applied to the study of the origin of life

The investigation of specific interactions among biological molecules must take into consideration the stereochemistry of the structures. Thus, models of the molecules are essential for describing the spatial organization of potentially interacting groups, and estimations of conformation are required for a description of spatial organization. Both the function of visualizing molecules, and that of estimating conformation through calculations of energy, are part of the molecular modeling system described in the present paper. The potential uses of the system in investigating some aspects of the origin of life rest on the assumption that translation of conformation from genetic elements to catalytic elements would have been required for the development of the first replicating systems subject to the process of biological evolution.

A Computer Aided Function Allocation and Evaluation System (CAFES)

The Computer Aided Function Allocation and Evaluation System (CAFES) is a crew systems design support tool based on human engineering methodology, computer aids, human performance data and a data management system. It is intended to support crew systems engineers in man-machine research, requirements analysis, design, test, training and maintenance systems development. The system of computer models comprising the CAFES system parallels the system development cycle and provides the required level of detail consistent with a given stage of system development. The principle objectives of the present development program are to facilitate timely application of all essential elements of human factors technology in systems development, using automatic data processing techniques for rapid analysis and evaluation of crew subsystem performance as it effects total systems effectiveness.

Practical developments in diabetes research.

A brief survey of current activities in diabetes research suggests that it is feasible in the near future to develop control systems that will closely mimic the normal glucoseinsulin system. A literature survey and preliminary experience in the use of on-line glucose sensing are described, as well as a computer model system applicable to both physiological and pathological studies of fuel homeostasis and to the practical development of an on-line glucose-insulin feedback system (an artificial beta cell).