Wherland Sandbox 3
ContentsIntroductionThe multicopper oxidases catalyze the reduction of oxygen to water, using a broad variety of substrates. They share a similar set of copper centers the type 1 (T1) or "blue copper" site..
Laccase from Trametes hirsutaThe laccase from trametes hirsuta has a single polypeptide chain with 3 domains colored green, blue, and yellow. The copper ions are represented by maroon spheres. The domains each form a beta barrel, illustrated when the structure is color coded by secondary structure. Adding the ligands to the Cu ions shows that they come from different domains. The ligands of the T1 Cu ion (His-395 and 458 and Cys-453) all come from the yellow domain 3. The ligands of one T3 Cu ion come from the yellow domain 3 (His-400 and 452) and the blue domain 1(His 111). The ligands of the other T3 Cu ion also come from the yellow and blue domains 3 and 1, but two (His-66 and 109) come from the blue domain 1 and only one from the yellow domain 3 (His-454). The ligands of the T2 Cu ion come from the blue domain 1 (His 64) and yellow domain 3 (His-398) and in addition there are three water molecules, one in the center of the TNC, one bridging the T3 Cu ions, and one just associated with the T2 Cu ion. None of the ligands come from the blue domain 2, the middle of the sequence. The ligands can be seen better without the surrounding chains, and with the bridging bridging residues between ligands (Trp-65, Ser-110, and Leu-399. The Cys-453 ligand of T1 connects directly to each of the T3 ions with a His ligand using the H452-C453-H454 segment. The two T3 ions are bridged by H398-L399-H400, T2 connects to one T3 by H64-W65-H66 and the other by H398-L399-H400. These bridges between Cu ions can serve as electron transfer (ET) pathways. Many of the MCOs have sugars on their surface. In this case there are 4 sugar chains. The exposure of the Cu centers is important to the control of their reactivity. Stop the spinning and manipulate the structure to see (click an atom to identify it) His-458 of the T1 copper and His-111 of one of the T3 Cu ions at the bottom of a deep pit. Peptide is gray, sugars are pale blue. DiseaseRelevanceStructural highlights | ||||||||||||
