RNAlib-2.2.0-RC3

Partition Function Cofolding. More...

+ Collaboration diagram for Partition Function for two hybridized Sequences:

Files

file  part_func_co.h
 Partition function for two RNA sequences.
 

Functions

cofoldF vrna_co_pf_fold (vrna_fold_compound *vc, char *structure)
 Calculate partition function and base pair probabilities of nucleic acid/nucleic acid dimers. More...
 
void vrna_co_pf_dimer_probs (double FAB, double FA, double FB, struct plist *prAB, const plist *prA, const plist *prB, int Alength, const vrna_exp_param_t *exp_params)
 Compute Boltzmann probabilities of dimerization without homodimers. More...
 
ConcEntvrna_co_pf_get_concentrations (double FcAB, double FcAA, double FcBB, double FEA, double FEB, const double *startconc, const vrna_exp_param_t *exp_params)
 Given two start monomer concentrations a and b, compute the concentrations in thermodynamic equilibrium of all dimers and the monomers. More...
 

Variables

int mirnatog
 Toggles no intrabp in 2nd mol.
 
double F_monomer [2]
 Free energies of the two monomers.
 

Detailed Description

Partition Function Cofolding.

To simplify the implementation the partition function computation is done internally in a null model that does not include the duplex initiation energy, i.e. the entropic penalty for producing a dimer from two monomers). The resulting free energies and pair probabilities are initially relative to that null model. In a second step the free energies can be corrected to include the dimerization penalty, and the pair probabilities can be divided into the conditional pair probabilities given that a re dimer is formed or not formed. See [1] for further details.

Function Documentation

cofoldF vrna_co_pf_fold ( vrna_fold_compound vc,
char *  structure 
)

Calculate partition function and base pair probabilities of nucleic acid/nucleic acid dimers.

This is the cofold partition function folding.

See also
vrna_get_fold_compound() for how to retrieve the necessary data structure
Parameters
vcthe fold compound data structure
structureWill hold the structure or constraints
Returns
cofoldF structure containing a set of energies needed for concentration computations.
void vrna_co_pf_dimer_probs ( double  FAB,
double  FA,
double  FB,
struct plist prAB,
const plist prA,
const plist prB,
int  Alength,
const vrna_exp_param_t exp_params 
)

Compute Boltzmann probabilities of dimerization without homodimers.

Given the pair probabilities and free energies (in the null model) for a dimer AB and the two constituent monomers A and B, compute the conditional pair probabilities given that a dimer AB actually forms. Null model pair probabilities are given as a list as produced by assign_plist_from_pr(), the dimer probabilities 'prAB' are modified in place.

Parameters
FABfree energy of dimer AB
FEAfree energy of monomer A
FEBfree energy of monomer B
prABpair probabilities for dimer
prApair probabilities monomer
prBpair probabilities monomer
AlengthLength of molecule A
exp_paramsThe precomputed Boltzmann factors
ConcEnt* vrna_co_pf_get_concentrations ( double  FcAB,
double  FcAA,
double  FcBB,
double  FEA,
double  FEB,
const double *  startconc,
const vrna_exp_param_t exp_params 
)

Given two start monomer concentrations a and b, compute the concentrations in thermodynamic equilibrium of all dimers and the monomers.

This function takes an array 'startconc' of input concentrations with alternating entries for the initial concentrations of molecules A and B (terminated by two zeroes), then computes the resulting equilibrium concentrations from the free energies for the dimers. Dimer free energies should be the dimer-only free energies, i.e. the FcAB entries from the cofoldF struct.

Parameters
FEABFree energy of AB dimer (FcAB entry)
FEAAFree energy of AA dimer (FcAB entry)
FEBBFree energy of BB dimer (FcAB entry)
FEAFree energy of monomer A
FEBFree energy of monomer B
startconcList of start concentrations [a0],[b0],[a1],[b1],...,[an][bn],[0],[0]
exp_paramsThe precomputed Boltzmann factors
Returns
ConcEnt array containing the equilibrium energies and start concentrations