integer nres,nsup,nstart_sup
      double precision c,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),cref_pdb(3,maxres2+2),
     &                nsup,nstart_sup,nstart_seq