Allosteric mechanism of proteins is essential in biomolecular signaling. An 
important aspect underlying this mechanism is the communication pathways 
connecting functional residues. Here, a Monte Carlo (MC) path generation 
approach is proposed and implemented to define likely allosteric pathways 
through generating an ensemble of maximum probability paths. The protein 
structure is considered as a network of amino acid residues, and inter-residue 
interactions are described by an atomistic potential function. PDZ domain 
structures are presented as case studies. The analysis for bovine rhodopsin and 
three myosin structures are also provided as supplementary case studies. The 
suggested pathways and the residues constituting the pathways are maximally 
probable and mostly agree with the previous studies. Overall, it is demonstrated 
that the communication pathways could be multiple and intrinsically disposed, 
and the MC path generation approach provides an effective tool for the 
prediction of key residues that mediate the allosteric communication in an 
ensemble of pathways and functionally plausible residues. The MCPath server is 
available at http://safir.prc.boun.edu.tr/clbet_server.