code: public static final List<String> getPDBresnum(int aligPos, AFPChain afpChain, Atom[] ca){
  		List<String> lst = new ArrayList<String>();
  		if ( aligPos > 1) {
  			System.err.println("multiple alignments not supported yet!");
  			return lst;
  		}
  
  		int blockNum = afpChain.getBlockNum();
  		int[] optLen = afpChain.getOptLen();
  		int[][][] optAln = afpChain.getOptAln();
  
  		if ( optLen == null)
  			return lst;
  
  		for(int bk = 0; bk < blockNum; bk ++)       {
  
  			for ( int i=0;i< optLen[bk];i++){
  
  				int pos = optAln[bk][aligPos][i];
  				if ( pos < ca.length) {
  					String pdbInfo = JmolTools.getPdbInfo(ca[pos]);
  					//lst.add(ca1[pos].getParent().getPDBCode());
  					lst.add(pdbInfo);
  				}
  			}
  
  		}
  		return lst;
  	}
docs: Return a list of pdb Strings corresponding to the aligned positions of the molecule.
  Only supports a pairwise alignment with the AFPChain DS.
  
  @param aligPos
  @param afpChain
  @param ca