PMC:1459172 / 9654-10736 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/1459172","sourcedb":"PMC","sourceid":"1459172","source_url":"https://www.ncbi.nlm.nih.gov/pmc/1459172","text":"The Vienna RNA Package currently implements three different models for handling the dangling-end contributions: They can be (a) ignored, (b) taken into account for every combination of adjacent bases and base pairs, or (c) a more complex model can be used in which the unpaired base can stack with at most one base pair. In cases (a) and (b) one can absorb the dangling end contributions in the loop energies (with the exception of contributions in the external loop). Model (c) strictly speaking violates the secondary structure model in that an unpaired base xi between two base pairs (xp, xi-1) and (xi+1, xq) has three distinct states with different energies: xi does not stack to its neighbors, xi stacks to xi-1, or xi+1. The algorithm then minimizes over these possibilities. While model (c) is the default for computing minimum free energy structures in most implementations such as RNAfold and mfold, it is not tractable in a partition function approach in a consistent way unless different positions of the dangling ends are explicitly treated as different configurations.","tracks":[]}