US-align: universal structure alignment of monomeric and complex proteins
   and nucleic acids

   References to cite:
   (1) Chengxin Zhang, Morgan Shine, Anna Marie Pyle, Yang Zhang
       (2022) Nat Methods. 19(9), 1109-1115.
   (2) Chengxin Zhang, Anna Marie Pyle (2022) iScience. 25(10), 105218.

   DISCLAIMER:
     Permission to use, copy, modify, and distribute this program for 
     any purpose, with or without fee, is hereby granted, provided that
     the notices on the head, the reference information, and this
     copyright notice appear in all copies or substantial portions of 
     the Software. It is provided "as is" without express or implied 
     warranty.