Systematic Methods for Exploring Conformational Space

As the name suggests, a systematic search explores the conformational space by making regular and predictable changes to the conformation. The simplest type of systematic search 

2 Ramachandran map for the alanine dipeptide (a) and glycine drpeptide 0), calculated using the AMBER force field [Weiner et al 1984]. In both cases contours are drawn at 1 0, 2 0 and 3 Okcal/mol above the lowest-energy conformation found 

A major drawback of the grid search is that the number of structures to be generated and mini-imsed increases in an exceptional fashion with the number of rotatable bonds, a phenomenon known as the combinatorial explosion. The number of structures generated is given by  

The efficiency of a depth-first search can be enhanced by discarding structures that violate some energetic or geometric criterion. Structures with high-energy steric interactions are 

Fig 9 8 The intramolecular parameters that may be checked when exploring the conformational space of a ring system 

---