RestraintLib 2019.10.1

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Restraints Libraries

RestraintLib API

Programs can use RestraintLib's API to calculate restraints programmatically without interacting with this web page. To see the format of the requests, check the API documentation.


The server generates external scripts with bond length and angle restraints for DNA and RNA oligonucleotides, for the phosphodiester (C-O-PO2-O-C) and monoester (C-O-PO3) groups, nitrogenous bases: adenine, guanine, thymine, uracil, cytosine, isocytosine, isoguanine, and ribose or 2’-deoxyribose sugar rings submitted as PDB files. The output restraint file is compatible with Refmac5, SHELXL and phenix.refine.

Please, upload a PDB file.

You may also want to standardize the placement of your macromolecule in the unit cell using ACHESYM


All submitted data will be deleted after 96 hours. Each submission gets a unique, random identification number. Accessing the results is only possible with the identification number.


To report errors, bugs, unusual behavior of the program, or to get help, please contact me at


To acknowledge the use of the server, please cite:

M.Kowiel, D.Brzezinski, M.Jaskolski (2016).
Conformation-dependent restraints for polynucleotides: I. clustering of the geometry of the phosphodiester group.
Nucleic Acids Res. doi: 10.1093/nar/gkw717. OpenAccess

M.Gilski, J.Zhao, M.Kowiel, D.Brzezinski, D.H.Turner, M.Jaskolski (2019).
Accurate geometrical restraints for Watson–Crick base pairs.
Acta Cryst. B75,

M.Kowiel, D.Brzezinski, M.Jaskolski (2019).
Conformation-dependent restraints for polynucleotides: The sugar moiety.
In preparation.