Re: CCL:G:Parametrization for Zinc / charges & vdW radius

 Viswanadhan wrote:
 :
 :
 : I would like to use CHELPG charges which necessitates the use of right
 : vdW radii. For neutral Zinc, the Bondi radius (J. Phys. Chem. 68. 441)
 : is 1.39 A, which is clearly not appropriate. Can any one point to recent
 : references or suggest a method? I will be happy to summarize the
 : responses (with regard to vdW radii & modeling the charge in the active
 : site of an enzyme for the Zinc ion).
 :
 : Vellarkad N. Viswanadhan
 :
 	Yes, what does constitute "good" vdW radii. In our work on Fe-S
 	centers in proteins we've noticed that the actual charges calculated
 	by CHELPG vary significantly depending on whether
 	you use Breneman&Wiberg radii or Gavizotti&Spackman radii.
 	Generally, Breneman & Wiberg based charges seem "better behaved"
 in
 	our systems.
 	Also, we've noticed that many groups use radii designed for other
 	purposes and "plug" these into the CHELPG algorithm.
 	What are the rationals people use in choosing their radii?
 	-Brian
 --
 =============================================================================
 |   .---------.| Brian W. Beck      |    E-mail Addresses:                  |
 |/\ |         ||--------------------|        brian()at()bert.chem.wsu.edu
 |
 || \\     WSU || Biochem/Biophysics |   brian_beck()at()wsu.edu
 |
 |\  -        *|| WSU ,  206 Fulmer  |  URL  http://elmo.chem.wsu.edu/~brian |
 | |           || Pullman, WA        |    VOICE    (509) 335-4083            |
 | \___________||       99164-4660   |      FAX    (509) 335-9688            |
 =============================================================================