subroutine elecont(lprint,ncont,icont,ist,ien) implicit none include 'DIMENSIONS' include 'DIMENSIONS.ZSCOPT' include 'DIMENSIONS.COMPAR' include 'COMMON.IOUNITS' include 'COMMON.CHAIN' include 'COMMON.INTERACT' include 'COMMON.FFIELD' include 'COMMON.NAMES' include 'COMMON.LOCAL' logical lprint integer i,j,k,ist,ien,iteli,itelj,ind,i1,i2,it1,it2,ic1,ic2 double precision rri,xi,yi,zi,dxi,dyi,dzi,xmedi,ymedi,zmedi, & xj,yj,zj,dxj,dyj,dzj,aaa,bbb,ael6i,ael3i,rrmij,rmij,r3ij,r6ij, & vrmij,cosa,cosb,cosg,fac,ev1,ev2,fac3,fac4,evdwij,el1,el2, & eesij,ees,evdw,ene double precision elpp6c(2,2),elpp3c(2,2),ael6c(2,2),ael3c(2,2), & appc(2,2),bppc(2,2) double precision elcutoff,elecutoff_14 integer ncont,icont(2,maxcont) double precision econt(maxcont) * * Load the constants of peptide bond - peptide bond interactions. * Type 1 - ordinary peptide bond, type 2 - alkylated peptide bond (e.g. * proline) - determined by averaging ECEPP energy. * * as of 7/06/91. * c data epp / 0.3045d0, 0.3649d0, 0.3649d0, 0.5743d0/ c data rpp / 4.5088d0, 4.5395d0, 4.5395d0, 4.4846d0/ data elpp6c /-0.2379d0,-0.2056d0,-0.2056d0,-0.0610d0/ data elpp3c / 0.0503d0, 0.0000d0, 0.0000d0, 0.0692d0/ data elcutoff /-0.3d0/,elecutoff_14 /-0.5d0/ ees=0.0d0 evdw=0.0d0 if (lprint) write (iout,'(a)') & "Constants of electrostatic interaction energy expression." do i=1,2 do j=1,2 rri=rpp(i,j)**6 appc(i,j)=epp(i,j)*rri*rri bppc(i,j)=-2.0*epp(i,j)*rri ael6c(i,j)=elpp6c(i,j)*4.2**6 ael3c(i,j)=elpp3c(i,j)*4.2**3 if (lprint) & write (iout,'(2i2,4e15.4)') i,j,appc(i,j),bppc(i,j),ael6c(i,j), & ael3c(i,j) enddo enddo ncont=0 do 1 i=ist,ien-2 xi=c(1,i) yi=c(2,i) zi=c(3,i) dxi=c(1,i+1)-c(1,i) dyi=c(2,i+1)-c(2,i) dzi=c(3,i+1)-c(3,i) xmedi=xi+0.5*dxi ymedi=yi+0.5*dyi zmedi=zi+0.5*dzi do 4 j=i+2,ien-1 ind=ind+1 iteli=itel(i) itelj=itel(j) if (j.eq.i+2 .and. itelj.eq.2) iteli=2 if (iteli.eq.2 .and. itelj.eq.2 & .or.iteli.eq.0 .or.itelj.eq.0) goto 4 aaa=appc(iteli,itelj) bbb=bppc(iteli,itelj) ael6i=ael6c(iteli,itelj) ael3i=ael3c(iteli,itelj) dxj=c(1,j+1)-c(1,j) dyj=c(2,j+1)-c(2,j) dzj=c(3,j+1)-c(3,j) xj=c(1,j)+0.5*dxj-xmedi yj=c(2,j)+0.5*dyj-ymedi zj=c(3,j)+0.5*dzj-zmedi rrmij=1.0/(xj*xj+yj*yj+zj*zj) rmij=sqrt(rrmij) r3ij=rrmij*rmij r6ij=r3ij*r3ij vrmij=vblinv*rmij cosa=(dxi*dxj+dyi*dyj+dzi*dzj)*vblinv2 cosb=(xj*dxi+yj*dyi+zj*dzi)*vrmij cosg=(xj*dxj+yj*dyj+zj*dzj)*vrmij fac=cosa-3.0*cosb*cosg ev1=aaa*r6ij*r6ij ev2=bbb*r6ij fac3=ael6i*r6ij fac4=ael3i*r3ij evdwij=ev1+ev2 el1=fac3*(4.0+fac*fac-3.0*(cosb*cosb+cosg*cosg)) el2=fac4*fac eesij=el1+el2 if (j.gt.i+2 .and. eesij.le.elcutoff .or. & j.eq.i+2 .and. eesij.le.elecutoff_14) then ncont=ncont+1 icont(1,ncont)=i icont(2,ncont)=j econt(ncont)=eesij endif ees=ees+eesij evdw=evdw+evdwij 4 continue 1 continue if (lprint) then write (iout,*) 'Total average electrostatic energy: ',ees write (iout,*) 'VDW energy between peptide-group centers: ',evdw write (iout,*) write (iout,*) 'Electrostatic contacts before pruning: ' do i=1,ncont i1=icont(1,i) i2=icont(2,i) it1=itype(i1) it2=itype(i2) write (iout,'(i3,2x,a,i4,2x,a,i4,f10.5)') & i,restyp(it1),i1,restyp(it2),i2,econt(i) enddo endif c For given residues keep only the contacts with the greatest energy. i=0 do while (i.lt.ncont) i=i+1 ene=econt(i) ic1=icont(1,i) ic2=icont(2,i) j=i do while (j.lt.ncont) j=j+1 if (ic1.eq.icont(1,j).and.iabs(icont(2,j)-ic2).le.2 .or. & ic2.eq.icont(2,j).and.iabs(icont(1,j)-ic1).le.2) then c write (iout,*) "i",i," j",j," ic1",ic1," ic2",ic2, c & " jc1",icont(1,j)," jc2",icont(2,j)," ncont",ncont if (econt(j).lt.ene .and. icont(2,j).ne.icont(1,j)+2) then if (ic1.eq.icont(1,j)) then do k=1,ncont if (k.ne.i .and. k.ne.j .and. icont(2,k).eq.icont(2,j) & .and. iabs(icont(1,k)-ic1).le.2 .and. & econt(k).lt.econt(j) ) goto 21 enddo else if (ic2.eq.icont(2,j) ) then do k=1,ncont if (k.ne.i .and. k.ne.j .and. icont(1,k).eq.icont(1,j) & .and. iabs(icont(2,k)-ic2).le.2 .and. & econt(k).lt.econt(j) ) goto 21 enddo endif c Remove ith contact do k=i+1,ncont icont(1,k-1)=icont(1,k) icont(2,k-1)=icont(2,k) econt(k-1)=econt(k) enddo i=i-1 ncont=ncont-1 c write (iout,*) "ncont",ncont c do k=1,ncont c write (iout,*) icont(1,k),icont(2,k) c enddo goto 20 else if (econt(j).gt.ene .and. ic2.ne.ic1+2) & then if (ic1.eq.icont(1,j)) then do k=1,ncont if (k.ne.i .and. k.ne.j .and. icont(2,k).eq.ic2 & .and. iabs(icont(1,k)-icont(1,j)).le.2 .and. & econt(k).lt.econt(i) ) goto 21 enddo else if (ic2.eq.icont(2,j) ) then do k=1,ncont if (k.ne.i .and. k.ne.j .and. icont(1,k).eq.ic1 & .and. iabs(icont(2,k)-icont(2,j)).le.2 .and. & econt(k).lt.econt(i) ) goto 21 enddo endif c Remove jth contact do k=j+1,ncont icont(1,k-1)=icont(1,k) icont(2,k-1)=icont(2,k) econt(k-1)=econt(k) enddo ncont=ncont-1 c write (iout,*) "ncont",ncont c do k=1,ncont c write (iout,*) icont(1,k),icont(2,k) c enddo j=j-1 endif endif 21 continue enddo 20 continue enddo if (lprint) then write (iout,*) write (iout,*) 'Electrostatic contacts after pruning: ' do i=1,ncont i1=icont(1,i) i2=icont(2,i) it1=itype(i1) it2=itype(i2) write (iout,'(i3,2x,a,i4,2x,a,i4,f10.5)') & i,restyp(it1),i1,restyp(it2),i2,econt(i) enddo endif return end