system("dsspcmbi $pdbstructure $dsspfile") and die "System called failed.";

##</code><code>##

$residuecombofile = "$combodir$residue1$residue2$residue3$out";

##</code><code>##

  if(open(PDB,"$pdbstructure"))

##</code><code>##

if ( -e $pdbstructure )

##</code><code>##

if ( -r $pdbstructure )

##</code><code>##

    if($flag == 0)

##</code><code>##

No structure file. Moving to next structure in list