Hi Dhiraj

The tpr file in gromacs is a binary run input file to run a simulation in gromacs - as such it will not be able to generate a useful tpr file from your YASARA output. What you need to do is to save the first frame as a pdb file and then pass the pdb file instead of the tpr file. Make sure that the content of the pdb file is the same as in the xtc file - i.e. that you save the water coordinates in the pdb file as well (else you may get gromacs complaining about atoms that are missing)

Hope this helps

Thanks Louis