The SHIFTASA web server is designed to accurately estimate residue-level fractional accessible surface area (fASA) from backbone and side-chain chemical shifts for water-soluble proteins. SHIFTASA accepts either a BMRB (BioMagResBank) formatted (NMR-STAR 2.1 or NMR-STAR 3.1) or a SHIFTY formatted file with at least 70-80% backbone and side-chain atoms having chemical-shifts assigned. The server generates predicted per-residue fASA values and a corresponding graphics plot in ~90-120 seconds (if the evolutionary profile-based prediction option is not used) or >300 seconds (if the evolutionary profile-based prediction option is used). Extensive testing indicates that SHIFTASA achieves a correlation coefficient between predicted and experimental values of 0.80-0.82 (tested on different control sets), which is significantly better than other existing methods. SHIFTASA combines the predictive power of machine learning with the added benefits of advanced sequence analysis to accurately estimate fASA via chemical shift data. If you use SHIFTASA please cite the following reference:

Reference: Noor E. Hafsa, David Arndt, David S. Wishart: Accessible Surface Area from NMR Chemical Shifts, Journal of Biomolecular NMR (2015): Vol. 62(3), p. 387-401

If you use backbone RCI result please cite: Mark V. Berjanskii, David S. Wishart (2005) A Simple Method To Predict Protein Flexibility Using Secondary Chemical Shifts.  Journal of the American Chemical Society, 127 (43), 14970 -14971


ShiftASA accepts BMRB NMR-STAR 2.1 and 3.1 formats, and SHIFTY format.
See format requirements and examples

Upload file with chemical shifts here:


Paste chemical shifts into the text box below:
IMPORTANT: If a file is selected for upload above, it will be used and content of the text box below will be ignored.


Additional Options
1) Correct Re-referencing of Chemical Shifts Yes (Default)  No 
2) Correct Neighbor Residue Effects Yes (Default)  No 
3) Use Evolutionary Profile- based Prediction Yes (Default)  No 
5) Produce Graphics Output Yes (Default)  No 
6) Predict Flexibility (Random Coil Index) from Chemical Shifts Yes (Default)  No 




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