Dear all,<br>that&#39;s probably a trivial problem but I couldn&#39;t solve it and I need some suggestions.<br>I have (for curious people, below I explain why) a file with periodic coordinates, ie the content of &quot;many&quot; contiguous unit cells whose asymmetric unit is a point. Can you suggest a program able to define unit cell and space group? I hope I explained myself...<br>
Thanks a lot!!<br><br><br>The framework:<br>I have communication problems with some physicist 
collaborators. I xtallised ferritin loaded with metal nanoparticles and 
they made some magnetic characterization on it. They asked me the cell 
parameters and I gave it (C2221). Then I realized that what they need is
 the directed distance between the metal nanoparticles. The problem is 
that the asymmetric unit is one ferritin and half, moreover the protein is a chiral/oriented object but the particle inside is not so, for their purposes, I think that the symmetry is different than mine. I told them but they don&#39;t understand me! They think that the cell, being base centred orthorhombic, implies that there is just a ferritin at each edge and at base centre. In an attempt to better describe the system, I used pymol to put a pseudoatom at the center of each ferritin and saved the coordinates. I sent them the coordinates and some explanatory pictures but they can&#39;t figure how the symmetry of protein lattice can be different than that of the metal particles lattice. Moreover, they do not understand why spherically symmetrical protein crystallizes in anything different from cubic lattice.  I give up! I&#39;d like to find the cell from the point of view of the metal particle, ask them to do their calculation on it and make a point.<br>