code: public Structure getStructureForPdbId(String pdbId) throws IOException, StructureException {
  		if(pdbId == null)
  			return null;
  		if(pdbId.length() != 4) {
  			throw new StructureException("Unrecognized PDB ID: "+pdbId);
  		}
  		while (checkLoading(pdbId)) {
  			// waiting for loading to be finished...
  
  			try {
  				Thread.sleep(100);
  			} catch (InterruptedException e) {
  				logger.error(e.getMessage());
  			}
  
  		}
  
  		Structure s;
  		if (useMmtf) {
  			logger.debug("loading from mmtf");
  			s = loadStructureFromMmtfByPdbId(pdbId);
  		}
  		else if (useMmCif) {
  			logger.debug("loading from mmcif");
  			s = loadStructureFromCifByPdbId(pdbId);
  		} else {
  			logger.debug("loading from pdb");
  			s = loadStructureFromPdbByPdbId(pdbId);
  		}
  		return s;
  	}
docs: Loads a structure directly by PDB ID
  @param pdbId
  @return
  @throws IOException
  @throws StructureException