source/cluster/wham/src-M/chainbuild.f

   1       subroutine chainbuild
   2 C
   3 C Build the virtual polypeptide chain. Side-chain centroids are moveable.
   4 C As of 2/17/95.
   5 C
   6       implicit real*8 (a-h,o-z)
   7       include 'DIMENSIONS'
   8       include 'COMMON.CHAIN'
   9       include 'COMMON.LOCAL'
  10       include 'COMMON.GEO'
  11       include 'COMMON.VAR'
  12       include 'COMMON.IOUNITS'
  13       include 'COMMON.NAMES'
  14       include 'COMMON.INTERACT'
  15       logical lprn
  16 C Set lprn=.true. for debugging
  17       lprn = .false.
  18 C
  19 C Define the origin and orientation of the coordinate system and locate the
  20 C first three CA's and SC(2).
  21 C
  22       call orig_frame
  23 *
  24 * Build the alpha-carbon chain.
  25 *
  26       do i=4,nres
  27         call locate_next_res(i)
  28       enddo
  29 C
  30 C First and last SC must coincide with the corresponding CA.
  31 C
  32       do j=1,3
  33         dc(j,nres+1)=0.0D0
  34         dc_norm(j,nres+1)=0.0D0
  35         dc(j,nres+nres)=0.0D0
  36         dc_norm(j,nres+nres)=0.0D0
  37         c(j,nres+1)=c(j,1)
  38         c(j,nres+nres)=c(j,nres)
  39       enddo
  40 *
  41 * Temporary diagnosis
  42 *
  43       if (lprn) then
  44
  45       call cartprint
  46       write (iout,'(/a)') 'Recalculated internal coordinates'
  47       do i=2,nres-1
  48         do j=1,3
  49           c(j,maxres2)=0.5D0*(c(j,i-1)+c(j,i+1))
  50         enddo
  51         be=0.0D0
  52         if (i.gt.3) be=rad2deg*beta(i-3,i-2,i-1,i)
  53         be1=rad2deg*beta(nres+i,i,maxres2,i+1)
  54         alfai=0.0D0
  55         if (i.gt.2) alfai=rad2deg*alpha(i-2,i-1,i)
  56         write (iout,1212) restyp(itype(i)),i,dist(i-1,i),
  57      &  alfai,be,dist(nres+i,i),rad2deg*alpha(nres+i,i,maxres2),be1
  58       enddo
  59  1212 format (a3,'(',i3,')',2(f10.5,2f10.2))
  60
  61       endif
  62
  63       return
  64       end
  65 c-------------------------------------------------------------------------
  66       subroutine orig_frame
  67 C
  68 C Define the origin and orientation of the coordinate system and locate
  69 C the first three atoms.
  70 C
  71       implicit real*8 (a-h,o-z)
  72       include 'DIMENSIONS'
  73       include 'COMMON.CHAIN'
  74       include 'COMMON.LOCAL'
  75       include 'COMMON.GEO'
  76       include 'COMMON.VAR'
  77       cost=dcos(theta(3))
  78       sint=dsin(theta(3))
  79       t(1,1,1)=-cost
  80       t(1,2,1)=-sint
  81       t(1,3,1)= 0.0D0
  82       t(2,1,1)=-sint
  83       t(2,2,1)= cost
  84       t(2,3,1)= 0.0D0
  85       t(3,1,1)= 0.0D0
  86       t(3,2,1)= 0.0D0
  87       t(3,3,1)= 1.0D0
  88       r(1,1,1)= 1.0D0
  89       r(1,2,1)= 0.0D0
  90       r(1,3,1)= 0.0D0
  91       r(2,1,1)= 0.0D0
  92       r(2,2,1)= 1.0D0
  93       r(2,3,1)= 0.0D0
  94       r(3,1,1)= 0.0D0
  95       r(3,2,1)= 0.0D0
  96       r(3,3,1)= 1.0D0
  97       do i=1,3
  98         do j=1,3
  99           rt(i,j,1)=t(i,j,1)
 100         enddo
 101       enddo
 102       do i=1,3
 103         do j=1,3
 104           prod(i,j,1)=0.0D0
 105           prod(i,j,2)=t(i,j,1)
 106         enddo
 107         prod(i,i,1)=1.0D0
 108       enddo
 109       c(1,1)=0.0D0
 110       c(2,1)=0.0D0
 111       c(3,1)=0.0D0
 112       c(1,2)=vbl
 113       c(2,2)=0.0D0
 114       c(3,2)=0.0D0
 115       dc(1,1)=vbl
 116       dc(2,1)=0.0D0
 117       dc(3,1)=0.0D0
 118       dc_norm(1,1)=1.0D0
 119       dc_norm(2,1)=0.0D0
 120       dc_norm(3,1)=0.0D0
 121       do j=1,3
 122         dc_norm(j,2)=prod(j,1,2)
 123         dc(j,2)=vbl*prod(j,1,2)
 124         c(j,3)=c(j,2)+dc(j,2)
 125       enddo
 126       call locate_side_chain(2)
 127       return
 128       end
 129 c-----------------------------------------------------------------------------
 130       subroutine locate_next_res(i)
 131 C
 132 C Locate CA(i) and SC(i-1)
 133 C
 134       implicit real*8 (a-h,o-z)
 135       include 'DIMENSIONS'
 136       include 'COMMON.CHAIN'
 137       include 'COMMON.LOCAL'
 138       include 'COMMON.GEO'
 139       include 'COMMON.VAR'
 140       include 'COMMON.IOUNITS'
 141       include 'COMMON.NAMES'
 142       include 'COMMON.INTERACT'
 143 C
 144 C Define the rotation matrices corresponding to CA(i)
 145 C
 146       theti=theta(i)
 147       phii=phi(i)
 148       cost=dcos(theti)
 149       sint=dsin(theti)
 150       cosphi=dcos(phii)
 151       sinphi=dsin(phii)
 152 * Define the matrices of the rotation about the virtual-bond valence angles
 153 * theta, T(i,j,k), virtual-bond dihedral angles gamma (miscalled PHI in this
 154 * program), R(i,j,k), and, the cumulative matrices of rotation RT
 155       t(1,1,i-2)=-cost
 156       t(1,2,i-2)=-sint
 157       t(1,3,i-2)= 0.0D0
 158       t(2,1,i-2)=-sint
 159       t(2,2,i-2)= cost
 160       t(2,3,i-2)= 0.0D0
 161       t(3,1,i-2)= 0.0D0
 162       t(3,2,i-2)= 0.0D0
 163       t(3,3,i-2)= 1.0D0
 164       r(1,1,i-2)= 1.0D0
 165       r(1,2,i-2)= 0.0D0
 166       r(1,3,i-2)= 0.0D0
 167       r(2,1,i-2)= 0.0D0
 168       r(2,2,i-2)=-cosphi
 169       r(2,3,i-2)= sinphi
 170       r(3,1,i-2)= 0.0D0
 171       r(3,2,i-2)= sinphi
 172       r(3,3,i-2)= cosphi
 173       rt(1,1,i-2)=-cost
 174       rt(1,2,i-2)=-sint
 175       rt(1,3,i-2)=0.0D0
 176       rt(2,1,i-2)=sint*cosphi
 177       rt(2,2,i-2)=-cost*cosphi
 178       rt(2,3,i-2)=sinphi
 179       rt(3,1,i-2)=-sint*sinphi
 180       rt(3,2,i-2)=cost*sinphi
 181       rt(3,3,i-2)=cosphi
 182       call matmult(prod(1,1,i-2),rt(1,1,i-2),prod(1,1,i-1))
 183       do j=1,3
 184         dc_norm(j,i-1)=prod(j,1,i-1)
 185         dc(j,i-1)=vbl*prod(j,1,i-1)
 186         c(j,i)=c(j,i-1)+dc(j,i-1)
 187       enddo
 188 cd    print '(2i3,2(3f10.5,5x))', i-1,i,(dc(j,i-1),j=1,3),(c(j,i),j=1,3)
 189 C
 190 C Now calculate the coordinates of SC(i-1)
 191 C
 192       call locate_side_chain(i-1)
 193       return
 194       end
 195 c-----------------------------------------------------------------------------
 196       subroutine locate_side_chain(i)
 197 C
 198 C Locate the side-chain centroid i, 1 < i < NRES. Put in C(*,NRES+i).
 199 C
 200       implicit real*8 (a-h,o-z)
 201       include 'DIMENSIONS'
 202       include 'COMMON.CHAIN'
 203       include 'COMMON.LOCAL'
 204       include 'COMMON.GEO'
 205       include 'COMMON.VAR'
 206       include 'COMMON.IOUNITS'
 207       include 'COMMON.NAMES'
 208       include 'COMMON.INTERACT'
 209       dimension xx(3)
 210
 211       dsci=dsc(iabs(itype(i)))
 212       dsci_inv=dsc_inv(iabs(itype(i)))
 213       alphi=alph(i)
 214       omegi=omeg(i)
 215       cosalphi=dcos(alphi)
 216       sinalphi=dsin(alphi)
 217       cosomegi=dcos(omegi)
 218       sinomegi=dsin(omegi)
 219       xp= dsci*cosalphi
 220       yp= dsci*sinalphi*cosomegi
 221       zp=-dsci*sinalphi*sinomegi
 222 * Now we have to rotate the coordinate system by 180-theta(i)/2 so as to get its
 223 * X-axis aligned with the vector DC(*,i)
 224       theta2=pi-0.5D0*theta(i+1)
 225       cost2=dcos(theta2)
 226       sint2=dsin(theta2)
 227       xx(1)= xp*cost2+yp*sint2
 228       xx(2)=-xp*sint2+yp*cost2
 229       xx(3)= zp
 230 cd    print '(a3,i3,3f10.5,5x,3f10.5)',restyp(itype(i)),i,
 231 cd   &   xp,yp,zp,(xx(k),k=1,3)
 232       do j=1,3
 233         xloc(j,i)=xx(j)
 234       enddo
 235 * Bring the SC vectors to the common coordinate system.
 236       xx(1)=xloc(1,i)
 237       xx(2)=xloc(2,i)*r(2,2,i-1)+xloc(3,i)*r(2,3,i-1)
 238       xx(3)=xloc(2,i)*r(3,2,i-1)+xloc(3,i)*r(3,3,i-1)
 239       do j=1,3
 240         xrot(j,i)=xx(j)
 241       enddo
 242       do j=1,3
 243         rj=0.0D0
 244         do k=1,3
 245           rj=rj+prod(j,k,i-1)*xx(k)
 246         enddo
 247         dc(j,nres+i)=rj
 248         dc_norm(j,nres+i)=rj*dsci_inv
 249         c(j,nres+i)=c(j,i)+rj
 250       enddo
 251       return
 252       end