QUARK is a computer algorithm for ab initio protein folding and protein structure prediction, which aims to construct the correct protein 3D model from amino acid sequence only. QUARK models are built from small fragments (1-20 residues long) by replica-exchange Monte Carlo simulation under the guide of an atomic-level knowledge-based force field. QUARK was ranked as the No 1 server in Free-modeling (FM) in CASP9 and CASP10 experiments. Since no global template information is used in QUARK simulation, the server is suitable for proteins which are considered without homologous templates.

Go to Job Q24927 to view an example of QUARK output. The description of predicted feature files can be seen in readme.txt. Questions about the QUARK server can be posted at the Service System Discussion Board.

Cut and paste your sequence (in FASTA format, less than 200 AA. Please submit bigger proteins to I-TASSER Server):

Or upload the sequence from your local computer:

Email: (mandatory, where results will be sent to. Only academic email accounts are acceptable.)

ID: (optional, your given name of the protein)

Optional: You can assign additional distance restraints for modeling (example is in distrestraint.txt; format is described in readme.txt).

D. Xu, Y. Zhang, Ab initio protein structure assembly using continuous structure fragments and optimized knowledge-based force field. Proteins, 2012, 80, 1715-1735 (download the PDF file and Support Information).


yangzhanglabumich.edu | (734) 647-1549 | 100 Washtenaw Avenue Ann Arbor, MI 48109-2218