ECEPP/3 program

The Empirical Conformational Energy Program for Peptides, ECEPP [63, 64], is one of the first empirical interatomic potentials whose derivation is based both on gas-phase and X-ray crystal data [65], It was developed in 1975 and updated in 1983 and 1992. The actual distribution (dated May, 2000) can be downloaded without charge for academic use. 

D.R. Ripoll, H.A. Scheraga, ECEPP Empirical Conformational Energy Program for Peptides, in The Encyclopedia of Computational Chemistry, Vol. 2,... 

Empirical conformational energy program for peptides (ECEPP) is the name of both a computer program and the force field implemented in that program. This is one of the earlier peptide force fields that has seen less use with the introduction of improved methods. It uses three valence terms that are fixed, a van der Waals term, and an electrostatic term. 

ECEPP Empirical conformational energy program for peptides... 

Some of the parameters that are used in the computer program ecepp (empirical conformational energy program for peptides) of Momany et al. (J. Phys. Chem. 1975, 79, 2361) are updated. The changes are based on experimental information that has become available since 1975,... 

We extended the use of our program Anneal-Conformer and the Amber force field for conformation searching of peptides [5]. We were also able to efficiently locate several new families of active conformations of Met-enkephalin [6]. Similar studies of Met-enkephalin Kawai [7] on a simplified ECEPP energy surface also demonstrated the efficiency of simulated annealing. 

Figure 5. Most probable conformation of poly[Ala -1-napAla] predicted from the ECEPP energy calculation. NAMOD version 3) program (ref. 16) was used to draw the molecular models.

By the early 1970s, molecular mechanics computer programs such as MMI and MM2 were available, running on the IBM 360. For proteins, ECEPP was developed by Harold A. Scheraga. - Countering the molecular mechanics approach, Michael J. S. Dewar modified John A. Pople s (complete) neglect-of-differential-overlap semiempirical quantum mechanical method (CNDO/2) to calculate quantities such as conformational stability and heats of formation. Such programs (MNDO) were necessarily slower than the empirical force field methods such as MM2 and ECEPP but still had fewer parameters and could account for the effects of polarization in aromatic systems. 

For this reason, the computer program ECEPP most frequently aj lied to the calculations of the conformational energy of peptides follows the ni-empirical approach. 

For a significant portion of this work, the ECEPP/3 (Empirical Conformational Energy Program for Peptides) [38] potential model is utilized. In this force field, it is assumed that the covalent bond lengths and bond angles are fixed at their equilibrium values. Then, the conformation is only a function of... 

The program PACK uses the name.date file and is connected with ECEPP/3 in order to evaluate the potential function, which is minimized by the local optimization solver NPSOL. 

ECEPP/3 Empirical Conformational Energy Program for Peptides... 

Table 3 lists chemists who have been most cited in chapters of prior volumes of our book series. Not surprisingly, all those listed are computational chemists, and many have written a chapter for Reviews in Computational Chemistry. It is interesting to notice how frequently the listed individuals are associated with developing a computer program that is well known in the lexicon of computational chemistry AMBER, CHARMM, Gaussian, UHBD, GROMOS, MM2/MM3, ECEPP, BOSS, DGEOM, MOPAC, DOCK, and so forth. 

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