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I-TASSER I-TASSER-MTD C-I-TASSER CR-I-TASSER QUARK C-QUARK LOMETS MUSTER CEthreader SEGMER DeepFold DeepFoldRNA FoldDesign COFACTOR COACH MetaGO TripletGO IonCom FG-MD ModRefiner REMO DEMO DEMO-EM DMFold SPRING COTH Threpp PEPPI BSpred ANGLOR EDock BSP-SLIM SAXSTER FUpred ThreaDom ThreaDomEx EvoDesign BindProf BindProfX SSIPe GPCR-I-TASSER MAGELLAN ResQ STRUM DAMpred

TM-score TM-align US-align MM-align RNA-align NW-align LS-align EDTSurf MVP MVP-Fit SPICKER HAAD PSSpred 3DRobot MR-REX I-TASSER-MR SVMSEQ NeBcon ResPRE TripletRes DeepPotential WDL-RF ATPbind DockRMSD DeepMSA FASPR EM-Refiner GPU-I-TASSER

BioLiP E. coli GLASS GPCR-HGmod GPCR-RD GPCR-EXP Tara-3D TM-fold DECOYS POTENTIAL RW/RWplus EvoEF HPSF THE-DB ADDRESS Alpaca-Antibody CASP7 CASP8 CASP9 CASP10 CASP11 CASP12 CASP13 CASP14

QUARK is a computer algorithm for ab initio protein structure prediction and protein peptide folding, 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 that do not have homologous templates in the PDB library. Go to example to view an example of QUARK output. The server is only for non-commercial use. 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. Example input

Or upload sequence from your computer:

Email: (mandatory, where results will be sent to.)

Password: (mandatory, click here if you do not have a QUARK password)

ID: (optional, name of the protein)


Advanced options [?]


QUARK Resource:

Reference:

  • D Xu and Y Zhang. Ab initio protein structure assembly using continuous structure fragments and optimized knowledge-based force field. Proteins, 2012, 80, 1715-1735 (2012). [PDF] [Support Information].
  • SM Mortuz, W Zheng, C Zhang, Y Li, R Pearce, Y Zhang. Improving fragment-based ab initio protein structure assembly using low-accuracy contact-map predictions. Nature Communications, 12: 5011 (2021). [PDF] [Support Information].

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