NQ-Flipper help page

This web site utilizes the https protocol.


Field name Description
PDB code Enter a PDB four letter code here. We retrieve our PDB files weekly from one of the PDB mirrors. Thus, any PDB code currently in PDB will be accessible on this web page, too.
File name If you have your own PDB-formatted coordinate file, upload it by pressing the "Choose" button.
Your file must have PDB-formatted ATOM records. If it also contains the CRYST1 record the complete crystal is recovered and used during all computations. (Otherwise, the crystal symmetry P1 is implicitly assumed.)
Valid file formats are: Plain ASCII, gzip (.gz) compressed or Unix compress (.Z) compressed files.
Model number If the PDB file contains multiple models, enter the desired model number here.
Altloc indicator If the PDB file contains residues with alternate location indicators, enter one here. This then confines split residues to those atoms with the specified altloc indicator. However, we suggest to submit only PDB files that have no altloc indicators.
Asparagine If you want to evaluate asparagine OD1 and ND2 atoms, check this box.
Glutamine If you want to evaluate glutamine OE1 and NE2 atoms, check this box.
NQ-Flipper rotates the amide plane atoms (Asn and Gln) by 180 degrees to compute the alternative conformation R2. The plane is rotated about the axis formed by CB-CG (Asn), or CG-CD (Gln). A former option to swap atom identities has been removed.

Linking this page

We provide a means for setting a link to the NQ-Flipper page which already computes the rotamer assignments for a specific PDB code. Simply use the following snippet in your href code:
where NXYZ is a four letter PDB code such as 1ra9. Optional arguments are ModelNr for any model number MN (eg. 1nmr, model 11) and AltLoc for any alternate location indicator AL (eg. 1mc2, altLoc A) present in the coordinate file:


If you have any further questions, feel free to contact us: Flipper-address


We thank Ralf Grosse-Kunstleve for kind permission to use his sglite crystallographic symmetry library in earlier versions of this software.