integer nres,nres0,nsup,nstart_sup,nend_sup,nstart_seq,ishift_pdb
      double precision c,cref,dc,xloc,xrot,dc_norm,t,r,prod,rt
      common /chain/ c(3,maxres2+2),dc(3,maxres2),xloc(3,maxres),
     & xrot(3,maxres),dc_norm(3,maxres2),nres,nres0
      common /rotmat/ t(3,3,maxres),r(3,3,maxres),prod(3,3,maxres),
     &                rt(3,3,maxres) 
      common /refstruct/ cref(3,maxres2+2),nsup,nstart_sup,nend_sup,
     &                nstart_seq,ishift_pdb