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Evaluation and Validation of Protein Structures (Single or Multiple)

Single (or Multiple) Model Protein Structure Analysis

VADAR molecules image 

VADAR (Volume, Area, Dihedral Angle Reporter) is a compilation of more than 15 different algorithms and programs for analyzing and assessing peptide and protein structures from their PDB coordinate data. The results have been validated through extensive comparison to published data and careful visual inspection.  The VADAR web server supports the submission of either PDB formatted files or PDB accession numbers.  VADAR produces extensive tables and high quality graphs for quantitatively and qualitatively assessing protein structures determined by X-ray crystallography, NMR spectroscopy, 3D-threading or homology modelling.  

resprox molecules image 

ResProx (Resolution-by-proxy or Res(p)) is a web server that predicts the atomic resolution of NMR protein structures using only PDB coordinate data as input. More specfically, ResProx uses machine learning techniques to accurately estimate (with a correlation coefficient of 0.92 between observed and calculated) the atomic resolution of a protein structure from 25 measurable features that can be derived from its atomic coordinates. Because atomic resolution is a simple and near-universal measure of structure quality (i.e. < 2.0 Å is good, > 4.0 Å is bad), ResProx offers X-ray crystallographers and NMR spectroscopists the opportunity to easily assess the accuracy and quality of their 3D protein structures. It also allows them to assess whether their refinement methods have made their structures better (or worse) than what the experimental data suggests. Furthermore, since coordinate data is common to both X-ray and NMR, ResProx should allow structural biologists to use a single, easily understood number to compare the structures determined by NMR with those determined by X-ray crystallography.

GeNMR 

GeNMR (GEnerate NMR structure) is a web server for generating 3D protein structures using NOE-derived distance restraints and NMR chemical shifts. The web server produces an ensemble of PDB coordinates within a period ranging from 20 minutes to 4 hours, depending on protein size, server load, quality and type of experimental information, and selected protocol options.

 http://shiftx.wishartlab.com/ 

With this form you can predict 1H, 13C and 15N chemical shifts for your favorite protein using only its PDB file as input. ShiftX uses a unique semi-empirical approach to calculate protein chemical shifts. Tests conducted on 47 different proteins indicate that program is able to achieve correlation coefficients between observed and calculated shifts of 0.911 (HA), 0.980 (CA), 0.996 (CB), 0.863 (CO), 0.909 (N), 0.741 (HN) and 0.907 (side H) with an RMS error of 0.23, 0.98, 1.10, 1.16, 2.43, 0.49, 0.30 ppm respectively. 

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for main-chain chemical shifts

RCI webserver predicts protein flexibility by calculating the Random Coil Index from backbone chemical shifts (Cα, CO, Cβ, N, Hα, NH) and estimating values of model-free order parameters as well as per-residue RMSF of NMR and MD ensembles from the Random Coil Index.  

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PREDITOR is a program for PREDIcting φ, ψ, χ1, and ω TORsion angles in proteins  from 13C, 15N and 1H chemical shifts and sequential homology. PREDITOR's accuracy in predicting φ and ψ is close to 90%. The average χ1 accuracy is 84% while the ω accuracy is 99.98% for trans peptide bond identification and 93% for cis peptide bond identification. Overall, the program is 35X faster and its predictions are approximately 20% better than existing methods.

MolProbity logo 

XPLOR-NIH

  http://homcos.pdbj.org/ 

HOMCOS : Searching and Modeling of 3D Structures of Complexes

HOMCOS(HOMology modeling of COmplex Structure) is a server for modeling complex 3D structures using 3D molecular similarities based on template complex 3D structures in PDB. For a given amino acid sequence or a chemical strucvure, the server provides list of contacting molecules in PDB, predicted complex 3D structure based on the template PDB structures.


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Build Homology model : Follow the link below
How to use MODELLER to build DIMER homology model with ligand?

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