AtomCache cache = new AtomCache();

cache.setPath("/tmp/");

FileParsingParameters params = cache.getFileParsingParams();

params.setLoadChemCompInfo(true);

StructureIO.setAtomCache(cache);

Structure structure = StructureIO.getStructure("4hhb");

The AtomCache not only provides access to PDB, it can also fetch Structure representations of protein domains, as defined by SCOP and CATH.

<pre>

// uses a SCOP domain definition

Structure domain1 = StructureIO.getStructure("d4hhba_");

// Get a specific protein chain, note: chain IDs are case sensitive, PDB IDs are not.

Structure chain1 = StructureIO.getStructure("4HHB.A");

</pre>

There are quite a number of external database IDs that are supported here. See the

<a href="http://www.biojava.org/docs/api/org/biojava/bio/structure/align/util/AtomCache.html#getStructure(java.lang.String)">AtomCache documentation</a> for more details on the supported options.