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What is the STAP2?
STAP2 refined the almost all NMR structures deposited in PDB (10,593) using statistical torsion angle potential and structurally- or experimentally- derived distance potential. The refined structures have more significantly improved structural quality than their initial NMR structure. The structural quality of initial and refined NMR structure is provided by various structural analysis. We believe that the STAP2 is useful to study of protein structure by providing refined NMR structures with high structural quality.
How to link?
• http://psb.kobic.re.kr/stap2/index.cgi?PDB ID

What's new?

Expanded datasets
• Most of NMR structures in PDB.
(10,593 structures, as of June 2015)
More detailed information
New method
• Flat-bottom distance potential that is newly developed NOE-like distance potential generated from initial NMR structure.
More detailed information
Various structural analysis
• 3D structure view, secondary structure scheme, tabular (score table) and graphical scores (radar charts).
More detailed information

How to STAP2?

PDB ID Search
• Please select the 'PDB ID' in field selection menu and enter the PDB ID of the NMR structure into search box.
• PDB ID should contain two or more characters (ex. '3g' or '3gb1' ).
Keyword Search
• If you do not have a PDB ID, you can find refined structure through a several keyword search.
• For example, if you select 'Classification' in field selection menu and enter 'membrane' into search box, you can see the list of membrane associated structures.

Biologically interesting example of refined structure

Structure validation scores


Calcium is the most plentiful mineral element found in your body, with phosphorous coming in second. This probably doesn't come as a surprise, since your bones are strengthened and supported by about two kilograms of calcium and phosphorous. Your body also uses a small amount of calcium, in the form of calcium ions, to perform more active duties. Calcium ions play essential roles in cell signaling, helping to control processes such as muscle contraction, nerve signaling, fertilization and cell division. Through the action of calcium pumps and several kinds of calcium binding proteins, cells keep their internal calcium levels 1000-10,000 times lower than the calcium levels in the blood. Thus when calcium is released into cells, it can interact with calcium sensing proteins and trigger different biological effects, causing a muscle to contract, releasing insulin from the pancreas, or blocking the entry of additional sperm cells once an egg has been fertilized.

• 2BBM refinement result


  1. First version of STAP : Yang, J.S., Kim, J.H., Oh, S., Han, G., Lee, S. and Lee, J. (2012) STAP Refinement of the NMR database: a database of 2405 refined solution NMR structures. Nucleic acids research, 40, D525-530.
  2. Method paper of STAP : Kim, T.R., Yang, J.S., Shin, S. and Lee, J. (2013) Statistical torsion angle potential energy functions for protein structure modeling: a bicubic interpolation approach. Proteins, 81, 1156-1165.
  3. Method paper of flat-bottom distance potential : Ryu, H., Kim, T.R., Ahn, S., Ji, S. and Lee, J. (2014) Protein NMR structures refined without NOE data. PloS one, 9, e108888
  4. Web server for NMR structure refinement : Ryu, H., Lim, GT., Sung, BH. and Lee, J. (2016) NMRe: a web server for NMR protein structure refinement with high-quality structure validation scores. Bioinformatics, 32.4, 611-613