Help for using MPRDOCK server

1. How to provide input for docked molecules

The MPRDOCK server is to predict the complex structure between proteins and nucleic acids through ensemble docking of multiple protein structures that are built based by homology modeling. Users need to provide input for the two molecule to be docked. The MPRDOCK server can accept four types of input for proteins:

• Upload your pdb file in PDB format.
• Provide your pdb file in PDB ID:ChainID (e.g. 2XNR:A).
• Copy and paste your protein sequence in FASTA format.
• Upload your protein sequence file in FASTA format

Only ONE type of input is needed for each molecule.

If more than one types of input are provided, the first one will be used. For the "PDB ID:ChainID" input, the user can provide one single chain ID or multiple chain IDs. For example, "2XNR:A" stands for the chain A of the pdb file of 2XNR; "1AHW:AB" stands for the chains A and B of the pdb file of 1AHW. If only a sequence is provided, the server will automatically constuct a model structure from a homologous template in the Protein Data Bank using a in-house modeling pipeline of HH Suite , Clustaw2, and MODELLER. Currently, the sequence input is only supported for proteins. For DNA/RNA, users need to submit their own structures for docking. In addition, users are also recommended to submit their own pdb file if the protein contains multiple chains, as our pipeline is currently designed to model single-chain proteins.

2.How to specify the binding site [optional]

The MPRDOCK performs global docking to predict the binding complexes between two molecules. Therefore, no information about the binding site is necessary for the docking job. However, the server also gives users the option to specify the binding site residues if such information is available, such that the predicted models will have a higher accuracy. Two types of binding site information can be provided.

• Binding site resdiues on the receptor or ligand.
The binding site residues are provided like this in the text box

	195:A, 203-206:A, 108:B

which stand for residues 195, 203-206 of chain A, and 108 of chain B. Note that the residues in a line must be separated by comma.

The binding site residues may also be submitted as a file that will look like this

	195:A
	203-206:A
	108:B

The residues are put on different lines in the file.


• Distance restraints between interacting residues
The users may directly provied such information on one line in the text box like

	195:A 236:B 8, 215-218:A 306:B 6

where the distance of residue 195 of chain A on the receptor and residue 236 of chain B on the ligand will be within 8 A; The distance of residues 215-218 of chain A on the receptor and residue 306 of chain B on the ligand will be within 6 A. Likewise, the above distance restraints can also be provided as a file that looks like this

	195:A 236:B 8 
	215-218:A 306:B 6