How to calculate lipophilic surface and momentum?

[Andrew Orry]

Q. How to calculate lipophilic surface and momentum?

A. 

# First calculate Lipophilic surface area:

show area surface a_//c*,s*,f*,Cl*,Br*,i*  a_//!h*

#then calculate the momentum.

make  grob surface a_//!h* a_//!h* name="full_surf"
make  grob surface a_//c*,s*,f*,Cl*,Br*,i*  a_//!h* name="lipo_surf"
lipoMom =  Mean(Xyz( lipo_surf  ) )- Mean(Xyz( full_surf  ) )
Length(lipoMom )

[Andrew Orry]

More details:

Hydrophobic momentum is in Angstroms (displacement of the center of mass of lipophilic surface w.r.t to center of mass of the entire surface).

To draw a vector: 

Arrow ‘grob':

g_lipoMom = Grob( "ARROW20" (Mean(Xyz(a_//!h*,vt*))-0.5*lipoMom )//(Mean(Xyz(a_//!h*,vt*))+0.5*lipoMom ))

display g_lipoMom yellow

For electrostatic surface:

dipole = Charge( a_//* )* Xyz( a_//* ) - Sum(Charge(a_//*)  )*Mean( Xyz(a_//* ) )

Arrow ‘grob':

g_electroMom = Grob( "ARROW20" (Mean(Xyz(a_//!h*,vt*))-0.5*dipole )//(Mean(Xyz(a_//!h*,vt*))+0.5*dipole ))

display g_electroMom magenta