H++ (web-based computational prediction of protonation states and pK of ionizable groups in macromolecules)

H++ is an automated system that computes pK values of ionizable groups in macromolecules and adds missing hydrogen atoms according to the specified pH of the environment. Given a (PDB) structure file on input, H++ outputs the completed structure in several common formats (PDB, PQR, AMBER inpcrd/prmtop) and provides a set of tools useful for analysis of electrostatic-related molecular properties. Why H++

If this is your first time using H++, please read the FAQ carefully.

H++ in more detail. Citations

Please report problems to the H++ team: ramu@vt.edu

NEWS:

4/2012 - You can cap protein termini using the procedure described here in the FAQ.
You can include specific buried water molecules using the procedure described here in the FAQ.

2/2012 - To improve efficiency, the titration curve is now only calculated in the experimentally accessible pH range from 0 to 12.
H++ now uses the latest AMBER force fields (ff10) for adding missing atoms and pK calculations.

8/2011 - New capability to build Amber explicit solvent topology and coordinate files, with ions

5/2011 - H++ now runs on a faster machine which increases the processing speed by a factor of 3, on average.
The less accurate GB option for electrostatic calculations has been removed.

6/2010 - Click the image below for a free, open-source utility (GEM) that allows coloring the surface of the H++ generated structures with the electrostatic potential.

NOTE: Current AMBER force fields in use: ff10 which includes ff99SB and ff99bsc0.