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Author Topic: Approach for building G-quadruplex models with 3'-3' and 5'-5'polarity inversion  (Read 10 times)

Offline muha

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Dear all,
I am working on the structural modeling of non-canonical G-quadruplexes (G4). Specifically, I am trying to build a monomolecular G4 model characterized by inversions of polarity (alternating 5'-3', 3'-3', 3'-5', and 5'-5' linkages) within the G-tracts.

I am looking for some guidance on how to build the starting structure: While DSSR is excellent at analyzing and rebuilding standard G4 topologies, i am not sure if it can handle these specific phosphodiester bond inversions.

Does DSSR have a built-in way to recognize and validate a chain that contains 3'-3' or 5'-5' linkages, or will it treat them as broken chains during analysis?
Are there specific commands in the latest DSSR releases (or via the mutate module) that allow for inverting the direction of a specific block of residues while maintaining the G-tetrad stacking geometry?

I am looking for a general methodology for handling these "inverted" backbone topologies in a way that remains compatible with subsequent Molecular Dynamics setups.
Once I find a stable workflow, I will be happy to summarize the steps for the community as per the forum guidelines.
Any suggestion is welcome!
Thank you for your time and for this useful resource.

Best

 

Funded by the NIH R24GM153869 grant on X3DNA-DSSR, an NIGMS National Resource for Structural Bioinformatics of Nucleic Acids

Created and maintained by Dr. Xiang-Jun Lu, Department of Biological Sciences, Columbia University