How can I get the exact 3D structure of the protein to use the PDB file for PPI docking

I am working on an uncharacterized protein, and I need to know its PPI with rna polymrase in humans. Please, how can I get the exact 3D structure of the protein to use the PDB file for PPI docking? Secondly, which web-based PPI docking server can you suggest?

pdbTools is a set of python command line scripts that manipulate the wwPDB protein and nucleic acid structure files. There are many programs, both open source and proprietary, that perform similar tasks; however, most of these tools are hidden in programs with more functionality. Thus, relatively simple calculations often involve learning a new program, compiling modules, and installing libraries.