Grasp was first developed by Anthony Nicholls and Kim Sharp in Barry Honig's laboratory in 1989, and the present version in 1992. While there were already software programs available, such as insight from Biosym Technologies, that could calculate isopotential contours, these approaches were limited because they could not capture local topology or shape, and the contours often extend significant distances away from the molecule. Therefore, Grasp was created to emphasize surfaces and electrostatics, and provides the best method currently available to visualize molecular surfaces and associated electrostatic potentials.
Atomic coordinates are the fundamental data structure from which everything else is derived.
External files in standard crystallographic format, PDB, are used. Grasp will then ask for the file name, and you can either select it from the list of PDB files in your account or enter the file name your self by typing it in. When PDB data for more than one molecule is read into Grasp the different molecules are assigned a number that correspond to the order in which the data was read. The molecule number is used to identify each molecule during all subsequent processes. For simple processes such as assigning colors and building molecular surfaces there is no need to create formal subsets of molecules.