1,328
edits
Servers for ligand topologies/parameters: Difference between revisions
Jump to navigation
Jump to search
→How to generate topology/parameter files for unknown ligand
(New page: == How to generate topology/parameter files for unknown ligand == What is meant here by unknown ligand is that it is not found in the standard monomer library in CCP4 or on the [http://x...) |
|||
| (4 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
== How to generate topology/parameter files for unknown ligand == | |||
CCP4 AceDRG ([http://www.ccp4.ac.uk/dist/checkout/acedrg/doc/Manual.pdf]) needs to be fed the SMILES string of your compound, and it returns the CIF file. | |||
Many compounds are actually already in the CCP4 dictionary. Finding out whether a compound is, is a two-step procedure: | |||
# Go to http://ligand-expo.rcsb.org/ and use the search option to find out whether the compound is already in the PDB | |||
# If it is, you now have a residue name. To check whether the compound is also in the CCP4 dictionary, just use the 'Get monomer' option in [[Coot]]. | |||
Within coot, you can | |||
* use Lidia to make a chemical diagram, press "Apply" to run Acedrg | |||
* or use Lidia to determine the SMILES string and use the "Make a Ligand" task in CCP4i2 | |||
You also might want to check the [http://xray.bmc.uu.se/hicup/ HIC-Up] website, and the NCBI Pubchem database at http://pubchem.ncbi.nlm.nih.gov/. The sdf file can be downloaded and converted to PDB format. | |||
Another solution to this problem is the [http://davapc1.bioch.dundee.ac.uk/programs/prodrg/ Dundee PRODRG server]. It is self-explanatory (you define the ligand structure by providing coordinates in PDB format, drawing molecule using [http://www.molinspiration.com/jme/ JME editor], etc.) and produces coordinates and topology/parameter descriptions in the following formats: | |||
- [http://www.rcsb.org/ PDB] | - [http://www.rcsb.org/ PDB] | ||
| Line 31: | Line 40: | ||
One inconvenience is that PRODRG server always names your new residue DRG and gives atoms some funny names (CAA, CAX, etc.). If you prefer to control the naming system, take the PDB output, rename residue/atoms to your liking and rerun it. | One inconvenience is that PRODRG server always names your new residue DRG and gives atoms some funny names (CAA, CAX, etc.). If you prefer to control the naming system, take the PDB output, rename residue/atoms to your liking and rerun it. | ||
== base pairing and base stacking == | |||
- [http://rna.ucsc.edu/pdbrestraints/ PDB coordinates to Restraints] - This Web-server generates custom RNA/DNA base stacking and base pairing restraints for crystallographic refinement. Input is in PDB format. Output is Pymol , CNS and PHENIX formatted. | |||