/**
* Reallocates an array with a new size, and copies the contents of the old array to the new
* array.
*
* @param oldArray the old array, to be reallocated.
* @param newSize the new array size.
* @return A new array with the same contents.
*/
public static Object resizeArray(Object oldArray, int newSize) {
int oldSize = java.lang.reflect.Array.getLength(oldArray);
@SuppressWarnings("rawtypes")
Class elementType = oldArray.getClass().getComponentType();
Object newArray = java.lang.reflect.Array.newInstance(elementType, newSize);
int preserveLength = Math.min(oldSize, newSize);
if (preserveLength > 0) System.arraycopy(oldArray, 0, newArray, 0, preserveLength);
return newArray;
}
/**
* Tries to detect symmetry in an alignment.
*
* <p>Conceptually, an alignment is a function f:A->B between two sets of integers. The function
* may have simple topology (meaning that if two elements of A are close, then their images in B
* will also be close), or may have more complex topology (such as a circular permutation). This
* function checks <i>alignment</i> against a reference function <i>identity</i>, which should
* have simple topology. It then tries to determine the symmetry order of <i>alignment</i>
* relative to <i>identity</i>, up to a maximum order of <i>maxSymmetry</i>.
*
* <p><strong>Details</strong><br>
* Considers the offset (in number of residues) which a residue moves after undergoing <i>n</i>
* alternating transforms by alignment and identity. If <i>n</i> corresponds to the intrinsic
* order of the alignment, this will be small. This algorithm tries increasing values of <i>n</i>
* and looks for abrupt decreases in the root mean squared offset. If none are found at
* <i>n</i><=maxSymmetry, the alignment is reported as non-symmetric.
*
* @param alignment The alignment to test for symmetry
* @param identity An alignment with simple topology which approximates the sequential
* relationship between the two proteins. Should map in the reverse direction from alignment.
* @param maxSymmetry Maximum symmetry to consider. High values increase the calculation time and
* can lead to overfitting.
* @param minimumMetricChange Percent decrease in root mean squared offsets in order to declare
* symmetry. 0.4f seems to work well for CeSymm.
* @return The order of symmetry of alignment, or 1 if no order <= maxSymmetry is found.
* @see IdentityMap For a simple identity function
*/
public static int getSymmetryOrder(
Map<Integer, Integer> alignment,
Map<Integer, Integer> identity,
final int maxSymmetry,
final float minimumMetricChange) {
List<Integer> preimage = new ArrayList<Integer>(alignment.keySet()); // currently unmodified
List<Integer> image = new ArrayList<Integer>(preimage);
int bestSymmetry = 1;
double bestMetric = Double.POSITIVE_INFINITY; // lower is better
boolean foundSymmetry = false;
if (debug) {
logger.trace("Symm\tPos\tDelta");
}
for (int n = 1; n <= maxSymmetry; n++) {
int deltasSq = 0;
int numDeltas = 0;
// apply alignment
for (int i = 0; i < image.size(); i++) {
Integer pre = image.get(i);
Integer intermediate = (pre == null ? null : alignment.get(pre));
Integer post = (intermediate == null ? null : identity.get(intermediate));
image.set(i, post);
if (post != null) {
int delta = post - preimage.get(i);
deltasSq += delta * delta;
numDeltas++;
if (debug) {
logger.debug("%d\t%d\t%d\n", n, preimage.get(i), delta);
}
}
}
// Metrics: RMS compensates for the trend of smaller numDeltas with higher order
// Not normalizing by numDeltas favors smaller orders
double metric = Math.sqrt((double) deltasSq / numDeltas); // root mean squared distance
if (!foundSymmetry && metric < bestMetric * minimumMetricChange) {
// n = 1 is never the best symmetry
if (bestMetric < Double.POSITIVE_INFINITY) {
foundSymmetry = true;
}
bestSymmetry = n;
bestMetric = metric;
}
// When debugging need to loop over everything. Unneeded in production
if (!debug && foundSymmetry) {
break;
}
}
if (foundSymmetry) {
return bestSymmetry;
} else {
return 1;
}
}
/**
* Takes a structure and sequence corresponding to an alignment between a structure or sequence
* and itself (or even a structure with a sequence), where the result has a circular permutation
* site {@link cpSite} residues to the right.
*
* @param first The unpermuted sequence
* @param second The sequence permuted by cpSite
* @param cpSite The number of residues from the beginning of the sequence at which the circular
* permutation site occurs; can be positive or negative; values greater than the length of the
* sequence are acceptable
* @throws StructureException
*/
public static AFPChain cpFastaToAfpChain(
ProteinSequence first, ProteinSequence second, Structure structure, int cpSite)
throws StructureException {
if (structure == null) {
throw new IllegalArgumentException("The structure is null");
}
if (first == null) {
throw new IllegalArgumentException("The sequence is null");
}
// we need to find the ungapped CP site
int gappedCpShift = 0;
int ungappedCpShift = 0;
while (ungappedCpShift < Math.abs(cpSite)) {
char c;
try {
if (cpSite <= 0) {
c = second.getSequenceAsString().charAt(gappedCpShift);
} else {
c = second.getSequenceAsString().charAt(first.getLength() - 1 - gappedCpShift);
}
} catch (StringIndexOutOfBoundsException e) {
throw new IllegalArgumentException("CP site of " + cpSite + " is wrong");
}
if (c != '-') {
ungappedCpShift++;
}
gappedCpShift++;
}
Atom[] ca1 = StructureTools.getRepresentativeAtomArray(structure);
Atom[] ca2 =
StructureTools.getRepresentativeAtomArray(
structure); // can't use cloneCAArray because it doesn't set parent
// group.chain.structure
ProteinSequence antipermuted = null;
try {
antipermuted =
new ProteinSequence(
SequenceTools.permuteCyclic(second.getSequenceAsString(), gappedCpShift));
} catch (CompoundNotFoundException e) {
// this can't happen, the original sequence comes from a ProteinSequence
logger.error(
"Unexpected error while creating protein sequence: {}. This is most likely a bug.",
e.getMessage());
}
ResidueNumber[] residues = StructureSequenceMatcher.matchSequenceToStructure(first, structure);
ResidueNumber[] antipermutedResidues =
StructureSequenceMatcher.matchSequenceToStructure(antipermuted, structure);
ResidueNumber[] nonpermutedResidues = new ResidueNumber[antipermutedResidues.length];
SequenceTools.permuteCyclic(antipermutedResidues, nonpermutedResidues, -gappedCpShift);
// nullify ResidueNumbers that have a lowercase sequence character
if (first.getUserCollection() != null) {
CasePreservingProteinSequenceCreator.setLowercaseToNull(first, residues);
}
if (second.getUserCollection() != null) {
CasePreservingProteinSequenceCreator.setLowercaseToNull(second, nonpermutedResidues);
}
// for (int i = 0; i < residues.length; i++) {
// if (residues[i] == null) {
// System.out.print("=");
// } else {
// System.out.print(sequence.getSequenceAsString().charAt(i));
// }
// }
// System.out.println();
// for (int i = 0; i < residues.length; i++) {
// if (nonpermutedResidues[i] == null) {
// System.out.print("=");
// } else {
// System.out.print(second.getSequenceAsString().charAt(i));
// }
// }
// System.out.println();
return buildAlignment(ca1, ca2, residues, nonpermutedResidues);
}
