[Chimera-users] creating a symmetric tetramer from a PDB file for a monomer?

Dear Chimera creators: Could you please let me know whether it is possible to create a tetramer structure with 4-fold symmetry from a PDB file for a monomer? Specifically, I want to create a structure of a voltage-gated K channel which has 4 monomers surrounding a central pore symmetrically, beginning with the PDB file for a monomer. There is no 'transformation matrix' in the PDB file to allow me to create the tetramer easily. Thank you very much for your help! Gea-Ny Tseng