BioJava:CookBook3:ModFinder

How can I identify protein modifications in a structure?

BioJava provide a module biojava3-modfinder for identification of protein pre-, co-, and post-translational modifications from structures. A list of protein modifications has been pre-loaded. It is possible to identify all pre-loaded modifications or part of them.

Example: identify and print all preloaded modifications from a structure

Set<ModifiedCompound> identifyAllModfications(Structure struc) {
	ProteinModificationIdentifier parser = new ProteinModificationIdentifier();
	parser.identify(struc);
	Set<ModifiedCompound> mcs = parser.getIdentifiedModifiedCompound();
	return mcs;
}

Example: identify phosphorylation sites in a structure

List<ResidueNumber> identifyPhosphosites(Structure struc) {
	List<ResidueNumber> phosphosites = new ArrayList<ResidueNumber>();
	ProteinModificationIdentifier parser = new ProteinModificationIdentifier();
	parser.identify(struc, ProteinModificationRegistry.getByKeyword("phosphoprotein"));
	Set<ModifiedCompound> mcs = parser.getIdentifiedModifiedCompound();
	for (ModifiedCompound mc : mcs) {
		Set<StructureGroup> groups = mc.getGroups(true);
		for (StructureGroup group : groups) {
			phosphosites.add(group.getPDBResidueNumber());
		}
	}
	return phosphosites;
}

Demo code to run the above methods

import org.biojava.nbio.structure.ResidueNumber;
import org.biojava.nbio.structure.Structure;
import org.biojava.nbio.structure.io.PDBFileReader;
import org.biojava.nbio.protmod.structure.ProteinModificationIdentifier;
 
public static void main(String[] args) {
	try {
		PDBFileReader reader = new PDBFileReader();
		reader.setAutoFetch(true);
 
		// identify all modificaitons from PDB:1CAD and print them
		String pdbId = "1CAD";
		Structure struc = reader.getStructureById(pdbId);
		Set<ModifiedCompound> mcs = identifyAllModfications(struc);
		for (ModifiedCompound mc : mcs) {
			System.out.println(mc.toString());
		}
 
		// identify all phosphosites from PDB:3MVJ and print them
		pdbId = "3MVJ";
		struc = reader.getStructureById(pdbId);
		List<ResidueNumber> psites = identifyPhosphosites(struc);
		for (ResidueNumber psite : psites) {
			System.out.println(psite.toString());
		}
	} catch(Exception e) {
		e.printStackTrace();
	}
}

See also

• How can I get the list of supported protein modifications?
• How can I define a new protein modification?