void PeptideCapProcessor::optimizeCapPosition(Chain& chain, bool start)
{
Vector3 translation;
Atom* axis = NULL;
Residue* cap = NULL;
std::vector<Atom*> a;
std::vector<Atom*> b;
Size nr = chain.countResidues();
// cap at the beginning of a peptide
if (start)
{
// put ACE-C to the center
for (AtomIterator it = chain.getResidue(1)->beginAtom(); +it; ++it)
{
if (it->getName() == "N")
{
translation = it->getPosition();
}
b.push_back(&*it);
}
cap = chain.getResidue(0);
for (AtomIterator it = cap->beginAtom(); +it; ++it)
{
a.push_back(&*it);
if (it->getName() == "C")
{
axis = &*it;
}
}
}
//cap at the end of a peptide
else
{
for (AtomIterator it = chain.getResidue(nr-2)->beginAtom(); +it; ++it)
{
if (it->getName() == "C")
{
translation = it->getPosition();
}
b.push_back(&*it);
}
cap = chain.getResidue(nr-1);
for (AtomIterator it = cap->beginAtom(); +it; ++it)
{
a.push_back(&*it);
if (it->getName() == "N")
{
axis = &*it;
}
}
}
//translate the anchor to origin
TranslationProcessor tlp;
tlp.setTranslation(translation*-1.0);
chain.apply(tlp);
//try all torsions
float largest_distance = 0.0;
float tmp_distance = 0.0;
float torsion = 0.0;
float step = 2.0;
TransformationProcessor tfp;
Matrix4x4 m;
m.setRotation( Angle(step, false), axis->getPosition());
tfp.setTransformation(m);
for (Position r = step; r <= 360; r+=step)
{
cap->apply(tfp);
tmp_distance = computeDistance(a,b);
if (largest_distance < tmp_distance)
{
largest_distance = tmp_distance;
torsion = r;
}
}
//apply best rotation angle
m.setRotation( Angle(torsion, false), axis->getPosition());
tfp.setTransformation(m);
cap->apply(tfp);
//now translate the protein back
tlp.setTranslation(translation);
chain.apply(tlp);
}
Processor::Result PeptideCapProcessor::operator() (Chain& chain)
{
TranslationProcessor tlp;
TransformationProcessor tfp;
Matrix4x4 m;
FragmentDB fragment_db("");
ReconstructFragmentProcessor reconstruct(fragment_db);
Residue* ace_residue = NULL;
Residue* nme_residue = NULL;
// check if a ACE cap was already added
bool add_cap = (chain.getResidue(0)->getName() != "ACE");
if (add_cap)
{
// create ACE-Cap
ace_residue = new Residue("ACE");
ace_residue->setProperty(Residue::PROPERTY__AMINO_ACID);
ace_residue->apply(reconstruct);
ace_residue->apply(fragment_db.normalize_names);
ace_residue->apply(fragment_db.build_bonds);
AtomIterator ace_atom = ace_residue->beginAtom();
//get all atoms needed to compute the transformation of the cap
Atom* cAtom = NULL;
Atom* ch3Atom = NULL;
Atom* oAtom = NULL;
Atom* h1Atom = NULL;
Vector3 h2Atom(0.0,0.0,0.0);
Vector3 h3Atom(0.0,0.0,0.0);
Vector3 nAtom(0.0,0.0,0.0);
while(+ace_atom)
{
if (ace_atom->getName() == "C")
cAtom = &*ace_atom;
else if (ace_atom->getName() == "CH3")
ch3Atom = &*ace_atom;
else if (ace_atom->getName() == "O")
oAtom = &*ace_atom;
++ace_atom;
}
std::vector<Atom*> to_remove;
AtomIterator n_atom = chain.getResidue(0)->beginAtom();
while (+n_atom)
{
if (n_atom->getName() == "1H")
{
h1Atom = &*n_atom;
n_atom->setName("H");
if (chain.getResidue(0)->getName() == "PRO")
to_remove.push_back(&*n_atom);
}
else if (n_atom->getName() == "N")
{
nAtom = n_atom->getPosition();
n_atom->apply(fragment_db.add_hydrogens);
}
++n_atom;
}
//compute position of OXT... map N of the last residue to it later
tlp.setTranslation(ch3Atom->getPosition()*-1.0);
ace_residue->apply(tlp);
m.setRotation( Angle(180.0 * Constants::PI / 180.0), cAtom->getPosition());
// map oxt and N of the last residue to the origin
tlp.setTranslation(m*oAtom->getPosition()*-1.0);
ace_residue->apply(tlp);
tlp.setTranslation(nAtom*-1.0);
chain.apply(tlp);
n_atom = chain.getResidue(0)->beginAtom();
while (+n_atom)
{
if (n_atom->getName() == "2H")
{
h2Atom = n_atom->getPosition();
to_remove.push_back(&*n_atom);
}
else if (n_atom->getName() == "3H")
{
h3Atom = n_atom->getPosition();
to_remove.push_back(&*n_atom);
}
++n_atom;
}
//rotate CH3 atom to 2H position
Angle angle = cAtom->getPosition().getAngle(h2Atom+h3Atom);
Vector3 rot_axis = (cAtom->getPosition()%(h2Atom+h3Atom)).normalize();
m.setRotation(angle,rot_axis);
tfp.setTransformation(m);
ace_residue->apply(tfp);
//insert ACE-Cap into chain
chain.insertBefore(*ace_residue,*chain.getResidue(0));
//Add Bond between ACE-Cap and Helix
n_atom = chain.getResidue(1)->beginAtom();
while (+n_atom)
{
if (n_atom->getName() == "N")
{
Bond* new_bond = cAtom->createBond(*n_atom);
new_bond->setOrder(Bond::ORDER__SINGLE);
break;
}
++n_atom;
}
//back translation
tlp.setTranslation(nAtom);
chain.apply(tlp);
//remove old hydrogens
for (Position a = 0; a < to_remove.size(); ++a)
{
delete to_remove[a];
}
//torsional optimzation of ACE
optimizeCapPosition(chain, true);
}
//##################################################################
add_cap = (chain.getResidue(chain.countResidues()-1)->getName() != "NME");
if (add_cap)
{
//create NME-Cap
nme_residue = new Residue("NME");
nme_residue->setProperty(Residue::PROPERTY__AMINO_ACID);
nme_residue->apply(reconstruct);
nme_residue->apply(fragment_db.normalize_names);
nme_residue->apply(fragment_db.build_bonds);
Residue* last_residue = chain.getResidue(chain.countResidues()-1);
//####################################################
Atom* nAtom = NULL;
Atom* ch3Atom = NULL;
Atom* hAtom = NULL;
AtomIterator nme_atom = nme_residue->beginAtom();
while (+nme_atom)
{
if (nme_atom->getName() == "N")
nAtom = &*nme_atom;
else if (nme_atom->getName() == "CH3")
ch3Atom = &*nme_atom;
else if (nme_atom->getName() == "H")
hAtom = &*nme_atom;
++nme_atom;
}
Vector3 anchor(( (hAtom->getPosition()-nAtom->getPosition()).normalize()
+ (ch3Atom->getPosition()-nAtom->getPosition()).normalize()).normalize()*-1.335);
tlp.setTranslation((anchor + nAtom->getPosition())*-1.0);
nme_residue->apply(tlp);
Atom* oxt = NULL;
Atom* cAtom = NULL;
AtomIterator c_atom = last_residue->beginAtom();
while (+c_atom)
{
if (c_atom->getName() == "OXT")
oxt = &*c_atom;
else if (c_atom->getName() == "C")
{
anchor = c_atom->getPosition();
cAtom = &*c_atom;
}
++c_atom;
}
tlp.setTranslation(anchor*-1.0);
chain.apply(tlp);
//transform cap to the old OXT position
Angle angle = nAtom->getPosition().getAngle(oxt->getPosition());
Vector3 rot_axis = (nAtom->getPosition()%(oxt->getPosition())).normalize();
m.setRotation(angle,rot_axis);
tfp.setTransformation(m);
nme_residue->apply(tfp);
//insert NME-Cap into chain
chain.insertAfter(*nme_residue, *last_residue);
//Add Bond between NME-Cap and Helix
Bond* new_bond = cAtom->createBond(*nAtom);
new_bond->setOrder(Bond::ORDER__SINGLE);
tlp.setTranslation(anchor);
chain.apply(tlp);
delete oxt;
//torsional optimzation of NME
optimizeCapPosition(chain, false);
}
return Processor::CONTINUE;
}
