Home > core > mergeCompartments.m

mergeCompartments

PURPOSE ^

mergeCompartments

SYNOPSIS ^

function [model, deletedRxns, duplicateRxns]=mergeCompartments(model,keepUnconstrained,deleteRxnsWithOneMet,distReverse)

DESCRIPTION ^

 mergeCompartments
   Merge all compartments in a model

   model                 a model structure
   keepUnconstrained     keep metabolites that are unconstrained in a
                         'unconstrained' compartment. If these are merged the
                         exchange reactions will most often be deleted (opt,
                         default false)
   deleteRxnsWithOneMet  delete reactions with only one metabolite. These
                         reactions come from reactions such as A[c] + B[c]
                         => A[m]. In some models hydrogen is balanced around
                         each membrane with reactions like this (opt,
                         default false)
   distReverse           distinguish reactions with same metabolites but
                         different reversibility as different reactions
                         (opt, default true)

   model                 a model with all reactions located to one compartment
   deletedRxns           reactions that were deleted because of only
                         having one metabolite after merging
   duplicateRxns         identical reactions that occurred in different
                         compartments and were deleted because they turned
                         to be duplicated after merging

   Merges all compartments into one 's' compartment (for 'System'). This can
   be useful for example to ensure that there are metabolic capabilities to
   synthesize all metabolites.

   NOTE: If the metabolite IDs reflect the compartment that they are in
   the IDs may no longer be representative.

   Usage: [model, deletedRxns, duplicateRxns]=mergeCompartments(model,keepUnconstrained,deleteRxnsWithOneMet,distReverse)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [model, deletedRxns, duplicateRxns]=mergeCompartments(model,keepUnconstrained,deleteRxnsWithOneMet,distReverse)
0002 % mergeCompartments
0003 %   Merge all compartments in a model
0004 %
0005 %   model                 a model structure
0006 %   keepUnconstrained     keep metabolites that are unconstrained in a
0007 %                         'unconstrained' compartment. If these are merged the
0008 %                         exchange reactions will most often be deleted (opt,
0009 %                         default false)
0010 %   deleteRxnsWithOneMet  delete reactions with only one metabolite. These
0011 %                         reactions come from reactions such as A[c] + B[c]
0012 %                         => A[m]. In some models hydrogen is balanced around
0013 %                         each membrane with reactions like this (opt,
0014 %                         default false)
0015 %   distReverse           distinguish reactions with same metabolites but
0016 %                         different reversibility as different reactions
0017 %                         (opt, default true)
0018 %
0019 %   model                 a model with all reactions located to one compartment
0020 %   deletedRxns           reactions that were deleted because of only
0021 %                         having one metabolite after merging
0022 %   duplicateRxns         identical reactions that occurred in different
0023 %                         compartments and were deleted because they turned
0024 %                         to be duplicated after merging
0025 %
0026 %   Merges all compartments into one 's' compartment (for 'System'). This can
0027 %   be useful for example to ensure that there are metabolic capabilities to
0028 %   synthesize all metabolites.
0029 %
0030 %   NOTE: If the metabolite IDs reflect the compartment that they are in
0031 %   the IDs may no longer be representative.
0032 %
0033 %   Usage: [model, deletedRxns, duplicateRxns]=mergeCompartments(model,keepUnconstrained,deleteRxnsWithOneMet,distReverse)
0034 
0035 if nargin<2
0036     keepUnconstrained=false;
0037 end
0038 if nargin<3
0039     deleteRxnsWithOneMet=false;
0040 end
0041 if nargin<4
0042     distReverse=true;
0043 end
0044 
0045 if ~isfield(model,'unconstrained')
0046     keepUnconstrained=false;
0047 end
0048 
0049 %Keep track of which reactions only contained one metabolite before the
0050 %merging as they are probable exchange reactions.
0051 if deleteRxnsWithOneMet==true
0052     reservedRxns=model.rxns(sum(model.S~=0)==1);
0053     if ~isempty(reservedRxns) && isfield(model,'unconstrained')
0054         %If there is no unconstrained field these reactions are probably
0055         %exchange reactions and shall be kept. If not then print a warning
0056         EM='There are reactions with only one metabolite. Cannot determine whether they are exchange reactions since there is no unconstrained field';
0057         dispEM(EM,false);
0058     end
0059 end
0060 
0061 %Loop through each metabolite, and if it is not unconstrained then change
0062 %the S matrix to use the metabolite with the lowest index in model.comps
0063 %instead
0064 uNames=unique(model.metNames);
0065 for i=1:numel(uNames)
0066     %Find all metabolites with this name..
0067     I=ismember(model.metNames,uNames(i));
0068     
0069     %Find the first of those that is not unconstrained. This is the one
0070     %that the other "un-unconstrained" should be changed to.
0071     if keepUnconstrained==true
0072         mergeTo=find(I & model.unconstrained==false,1);
0073         
0074         %This could happen if there is only one metabolite and it is
0075         %unconstrained
0076         if isempty(mergeTo)
0077             continue;
0078         end
0079     else
0080         mergeTo=find(I,1);
0081     end
0082     I(mergeTo)=false; %Do not do anything for itself
0083     I=find(I);
0084     
0085     %Go through each of the metabolites with this name and update them to
0086     %mergeTo
0087     for j=1:numel(I)
0088         if keepUnconstrained==true && model.unconstrained(I(j))==true
0089             continue;
0090         end
0091         %Update the S matrix
0092         model.S(mergeTo,:)=model.S(mergeTo,:)+model.S(I(j),:);
0093         model.S(I(j),:)=0;
0094     end
0095 end
0096 
0097 %Remove all metabolites that are no longer used (with a bit of a trick)
0098 model=removeReactions(model,{},true);
0099 
0100 %Update all mets so that they are in compartment "s" with id "1"
0101 model.compNames={'System'};
0102 model.comps={'s'};
0103 model.compOutside={''};
0104 model.metComps=ones(numel(model.mets),1);
0105 
0106 %Add exchange mets to another compartment "b" with id "2"
0107 if keepUnconstrained==true
0108     model.compNames=[model.compNames; {'Unconstrained'}];
0109     model.comps=[model.comps; {'b'}];
0110     model.compOutside=[model.compOutside; {'s'}];
0111     model.metComps(model.unconstrained~=0)=2;
0112 end
0113 
0114 %Transport reactions on the form A <=> B will have been deleted by the
0115 %merging. Remove those reactions
0116 model=removeMets(model,{},false,true,true);
0117 
0118 if deleteRxnsWithOneMet==true
0119     I=model.rxns(sum(model.S~=0)==1);
0120     
0121     %Delete the reactions that contain only one metabolite after the
0122     %merging but not before
0123     deletedRxns=setdiff(I,reservedRxns);
0124     model=removeReactions(model,deletedRxns,true,true);
0125 else
0126     deletedRxns={};
0127 end
0128 
0129 %And then finally merge the identical reactions
0130 [model, ~, duplicateRxns]=contractModel(model,distReverse);
0131 end

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