What it does
The UNAFold server provides mfold forms for nucleic-acid folding and related thermodynamic calculations.
The mfold DNA form accepts FASTA input, removes non-alphabet characters and supports optional pairing constraints. Select linear/circular DNA, temperature from 0–100 °C, sodium/magnesium conditions and oligomer/polymer correction before choosing suboptimality and structure-output options. Both immediate and batch DNA jobs are limited to 2,400 bases; batch delivery uses email. Its ionic-condition guide limits oligomer sodium to 0.01–1 M and magnesium to at most 0.1 M, with applicability tied to short stems; polymer correction requires zero magnesium. Output documentation describes PNG/JPG, PDF and PostScript structure plots. These are thermodynamic predictions under the selected conditions; other RNA and UNAFold modes have separate rules.
Strengths
- DNA and RNA folding forms
- Optional constraints and documented model references
Watch out for
- The reviewed DNA form limits immediate and batch jobs to 2,400 bases. Other RNA modes and UNAFold applications can have different limits.
Best for
- Planning a defined nucleic-acid folding calculation
Sources
- DNA Folding Form (Oct 26, 2026)
- mfold Ionic Correction and Plot Output Scope (Oct 26, 2026)