Subject: QUAC PAC 1.1 - quality charge states and charges of small molecules and proteins

From: George Vacek <vacek!at!eyesopen.com>
Date: Thu, 30 Sep 2004 11:37:02 -0600

OpenEye announces the release of QUAC PAC 1.1, a suite of programs that 
generates high-quality charge states and charges for both small 
molecules and proteins. QUAC PAC offers everything necessary to do 
charges right. It includes pKa state and tautomer enumeration in order 
to get correct protonation states, partial charges using multiple models 
that cover a range of speed and quality, and electrostatic potential map 
construction and storage.

QUAC PAC's highest quality partial charges are obtained for ligand 
molecules using the AM1-BCC model, designed to reproduce HF/6-31G* 
quality charges at about 1 molecule per second for drug-sized molecules. 
  For screening purposes, QUAC PAC also offers the VC2003 and MMFF 
partial charges models, which can process about 400 and 1000 molecules 
per second, respectively. QUAC PAC's enumerates all reasonable pKa and 
tautomeric states, ensuring that they will be in the ensemble for 
subsequent screens. For proteins, QUAC PAC determines pKa via 
Poisson-Boltzmann (PB) electrostatics.

One of the most novel components of QUAC PAC is the ability to handle 
PREPS (Polynomial Representation of Electrostatic Potential Surfaces). 
PREPS is a compact method of storing through-space potential 
distributions, in a 184-character string, so that they may be attached 
to any molecule's structure file so that it can be quickly used on the 
fly, rather than having to be recalculated.

For further information, please visit www.eyesopen.com or contact 
business!at!eyesopen.com.

Regards,
George Vacek
VP, Business Development
OpenEye Scientific Software