Welcome to the bifold Web Server

The bifold server takes two nucleic acid sequences, either RNA or DNA, and folds them into their lowest free energy conformation. Predicted base pairs can be between strands (bimolecular) or within strands (unimolecular).

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If you need specific help using the bifold server, please click here.

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RNAstructure tools have been updated to version which includes several improvements.
Please contact us with any questions or issues regarding this update.

Example sequences have been displayed.

Select Sequence 1 Input:

Select Sequence File 1:

- OR -
Enter your sequence title and content below (replaces upload if present).
Please enter nucleotides only, no headers or comments in content.
Valid nucleotides are A, C, G, T, U, and X (unknown nucleotide). Lower case nucleotides are forced single stranded in calculation.

Sequence 1 Title: Sequence 1:

Select Sequence 2:

Select Sequence File 2:

Sequence 2 Title: Sequence 2:

Select Nucleic Acid Type:

DNA:
RNA:

Select bifold Options:

Default Data If a default value is left blank, the value is treated as if it was not changed at all. Maximum % Energy Difference: Maximum Number of Structures: Window Size: Maximum Loop Size: Temperature (K):

Optional Data

Forbid Intramolecular Pairs:

Designate Address to Email Results:

Address to Email Results: