CycleFold predicts both canonical and non-canonical base pairs using nucleotide cyclic motifs (Parisien & Major, 2008). It predicts either lowest free energy structures or base pairing probabilities.
By default, the minimum free energy structure is predicted. The options, below, can change the behavior to predicting base pair probabilities or using predicted base pair probabilities to predict the maximum expected accuracy structure. If multiple sequences are entered, the TurboFold mode can also be specified. All output is to standard out.
CycleFold requires the environment variable, CYCLEFOLD_DATAPATH, be set to the location of the datatables, which reside in RNAstructure/CycleFold/datafiles.
USAGE: CycleFold <seq file> [options]
The name of a fasta file that contains the sequence.
|-b, -B, --bigloops
||Allow large internal loops or hairpin loops, whose energies are not tabulated in the NCM model. This is sometimes necessary for structure calculations with constraints (-c or -ct opions).
|-fc, -FC, --fastaConstraints
|| Specify that the input fasta file contains secondary structure constraints (in dot-bracket format) to be applied to each structure.
|-h, -H, --help
||Display the usage details message.
|-m, -M, --maxExpect
||Specify that a MaxExpect calculation should be performed. (This predicts a structure composed of probable base pairs.)
|-p, -P, --partitionfunction
||Specify that pair probabilities should be printed.
|-s, -S, --seqFormat
||Switch the expected input from FASTA to .seq format.
|-t, -T, --turbo
||Specify that a TurboFold calculation should be performed. TurboFold writes all of the structures or pair probability tables, with their labels, in the order that they were provided.
|-u, -U, --unpairingConstraints
||Toggle whether restraints should be treated as unpairing constraints.
|-v, -V, --version
||Display the version and copyright information.
|-c, -C, --constraintFile
Specify a constraint file to be applied (in constraint file format).
Default is to have no constraints applied.
|-ct, -CT, --constrainCt
|| Specify a constraint file to be applied (in ct format).
|-g, -G, --gamma
|| Set gamma, the weighting parameter for extrinsic information in the
turbo calculation. The default is 0.6.
|-i, -I, --iterations
|| Set the number of iterations for the turbo calculation. The default is 2.
Unlike most other programs in RNAstructure, lowercase nucleotides are allowed to base pair.
Reuter, J.S. and Mathews, D.H.
"RNAstructure: software for RNA secondary structure prediction and analysis."
BMC Bioinformatics, 11:129. (2010).
- Sloma, M.F. and Mathews, D.H.
"Accurate prediction of RNA non-canonical pairs using probability estimates."
- Parisien, M. and Major, F.
"The MC-Fold and MC-Sym pipeline infers RNA structure from sequence data."
Nature, 452: 51-55. (2008).