Instructions to use GRASP
Color a molecular surface by electrostatic potential
Follow these instructions, (page 66 of manual)
Assign charges, "Read: Radius/Charge File (+Assing):full.crg"
Calculate the potential map, "Calculate: New Potential Map"
Constuct molecular surface, "Build: Molecular Surface:All atoms"
After the white molecular surface appears, change the display mode, "Display:
Alter: Molecular Surface: (Color Surface by): (Surface Display Mode)"
Use right mouse button to select command options
From menu, select "Read:PDB File:Enter File Name:"
The text window will pop forward, type .pdb file name, with full directory
You should then see a stick drawing of your molecule, with the unit cell
Calculate potential values of all atoms, "Calculate: Pot. via Map at
Surfaces/Atoms:All Atoms:All Surfaces"
Options in "()" mean accept the default. Click the mouse off the menu.
You shouldn't see a change in the display yet.
Colors will probably be faint.
Toggle the ">-<" part of the color scale bar to decrease the right and
left numbers until the desired contrast level is obtained (usually between
`0 and 20 in absolute values).
Display surface potential and curvature side by sided
Calculate the surface potentail map and displayed as described above
Calculate the curvature, "Calculate: Surface Curvature (+Display): All
Surfaces: All Atoms"
This takes awhile, wait until the displayed map turns green and grey
Change to split screen mode, "Display: Stereo/Split ON: Dials to Both"
You should see two green/grey images.
With the bottom right dial, move the two surfaces apart, if necessary.
Scale with the right dial button above the separation dial.
Change the left surface to potential, "Display: Alter: Molecular Surface:
Potential: (Surface Display Mode):Left"