|Rosetta 3.2 Release Manual|
fixbbapplication is maintained by Brian Kuhlman's lab. Send questions to firstname.lastname@example.org
mini/test/integration/tests/fixbbfor an example of fixed backbone design protocol and input files. A production run can be made from the
commandfile by adding the flags -ex1 and -ex2 for the fullatom run. The centroid-mode run is already a "production run" in that it cannot be made to take more time than it does already.
The majority of the classes for the fixbb application live in
src/core/pack. The main interface class is the
PackerTask which lives in
src/core/pack/task. Rotamers are held in instances of class <core>RotamerSet which are in turn held in an instance of class
RotamerSets; these classes live in
src/core/pack/rotamer_set. Rotamer-pair energies are held in one of several "interaction graph" classes, which live in namespace
core::pack::interaction_graph. The annealer classes live in
src/core/pack/annealer The application itself lives in
src/apps/public/design/fixbb.cc and invokes the
PackRotamersMover that lives in
There are many ways to control the way rotamers are sampled and at which positions design should be attempted. There are several command line flags that apply to all residues. In addition, a "resfile" can specify the way particular residues are to be treated. By default,
fixbb will attempt to redesign all residues using all amino acids.
Fixed-backbone design works best when paired with a softened Lennard-Jones term [Dantas et al. 2003] which helps overcome the problem of discrete rotamer building (not default). The score function used may be controlled on the command line by specifying a weights file (or both a weights file and a weights-patch file). By default, the fixbb application uses the "score12" score function by default (the combination of "standard.wts" and "score12.wts_patch").
There are three serious limitations worth considering: 1) fixed backbone design does not sample backbone conformation space, and therefore cannot guarantee that the new sequence will fold into the desired backbone conformation; 2) since the underlying combinatorial optimization problem is NP-Complete, and our approximation of it is stochastic, the output from separate
fixbb jobs will vary; 3) the score function used is imperfect such that even the best-scoring designs might not express or fold.
At least one input pdb file must always be given. A list of pdbs can be specified on the command line, or in a list file:
-s <pdb1> <pdb2> <pdb3> ...
where listfname is a simple text file that has one pdb file name per line. The fixbb application will apply the PackRotamersMover to each of the input structures given.
A single resfile may be specified on the command line with the -resfile <fname> flag. This resfile will be used for all structures that are input. If a resfile cannot be applied to all the structures, then the job should be split up. The resfile format is described here Resfile syntax and conventions Resfile.
-s <pdb> <pdb2> A list of one or more pdbs to run <code>fixbb</code> upon. -l <listfile> A file that lists one or more pdbs to run <code>fixbb</code> upon. -resfile <fname> The resfile that is to be used for this job -nstruct <int> The number of iterations to perform per input structure; e.g. with 10 input structures and an -nstruct of 10, 100 trajectories will be performed.
Interaction Graph (Default is to precompute all rotamer pair energies)
-linmem_ig <int> Activate the linear-memory interaction graph [Leaver-Fay et al. 2008] -lazy_ig Activate the lazy interaction graph
-ex1 Increase chi1 rotamer sampling for buried* residues +/- 1 standard deviation -ex1_aro Increase chi1 rotamer sampling for buried* aromatic** residues +/- 1 standard deviation -ex2 Increase chi2 rotamer sampling for buried* residues +/- 1 standard deviation -ex2_aro Increase chi2 rotamer sampling for buried* aromatic** residues +/- 1 standard deviation -ex3 Increase chi3 rotamer sampling for buried* residues +/- 1 standard deviation -ex4 Increase chi4 rotamer sampling for buried* residues +/- 1 standard deviation -ex1:level <int> Increase chi1 sampling for buried* residues to the given sampling level -ex1_aro:level <int> : Increase chi1 sampling for buried* aromatic residues to the given sampling level -ex2:level <int> Increase chi1 sampling for buried* residues to the given sampling level -ex2_aro:level <int> : Increase chi1 sampling for buried* aromatic residues to the given sampling level -ex3:level <int> Increase chi1 sampling for buried* residues to the given sampling level -ex4:level <int> Increase chi1 sampling for buried* residues to the given sampling level -preserve_input_cb Do not idealize the CA-CB bond vector -- instead, use the CB coordinates of the input pdb. -use_input_sc Include the side chain from the input pdb. False by default. Including the input sidechain is "cheating" if your goal is to measure sequence recovery, but a good idea if your goal is to redesign the input sequence for eventual synthesis.
Buried residues are those with CBeta-neighbors >= threshold (default 18) within 10 Angstroms. This threshold can be controlled by the -extrachi_cutoff flag.
-extrachi_cutoff <int> : Set the number of cbeta neighbors (counting its own) at which a residue is considered buried. A value of "1" will mean that all residues are considered buried for the purpose of rotamer building.
Aromatic residues are HIS, TYR, TRP, and PHE. Note: Including both -ex1 and -ex1_aro does not increase the sampling for aromatic residues any more than including only the -ex1 flag. If however, both -ex1 and -ex1_aro:level 4 are included on the command line, then aromatic residues will have more chi1 rotamer samples than non aromatic residues. Note also that -ex1_aro can *only increase* the sampling for aromatic residues beyond that for non-aromatic residues. -ex1:level 4 and -ex1_aro:level 1 together will have the same effect as -ex1:level 4 alone.
(Default is the original annealer used in [Kuhlman et al. 2003])
-multi_cool_annealer <int> Use an alternate annealer that spends more time at low temperatures. This annealer produces consistently lower energies than the standard annealer.
-database <path/to/minirosetta_database> Specify the location of the minirosetta_database (required) -overwrite Overwrite the output files, even if they already exist. -minimize_sidechains Follow the packing phase with gradient-based minimization of the sidechains for residues that were either repacked or designed in the packing phase. -min_type <string> When combined with the -minimize_sidechains flag, specifies the line-search algorithm to use in the gradient-based minimization . "dfpmin" by default. -score:weights <wts_file> Set the weights file to be used. -score:weights_patch <patch_file> Set the weights patch file to be used.
If neither the -score:weights nor the -score:weights_patch flags are used, then "score12" will be used by default.
-constant_seed Fix the random seed -jran <int> Specify the random seed; if unspecified, and -constant_seed appears on the command line, then the seed 11111111 will be used
fixbb application uses the JD2 job-distributor, it respects all of the jd2 flags that control output.