Crystal structure of a laccase from Melanocarpus albomyces with an intact trinuclear copper site.
We have crystallized the ascomycete laccase from Melanocarpus albomyces with all four coppers present and determined the crystal structure at 2.4 A resolution. The enzyme is heavily glycosylated and consists of three cupredoxin-like domains, similar to those found in the Cu-depleted basidiomycete laccase from Coprinus cinereus. However, there are significant differences in the loops forming the substrate-binding pocket. In addition, the crystal structure of the M. albomyces laccase revealed elongated electron density between all three coppers in the trinuclear copper site, suggesting that an oxygen molecule binds with a novel geometry. This oxygen, required in the reaction, may enter the trinuclear site through the tunnel, which is open in the structure of the C. cinereus laccase. In contrast, the C-terminus on the M. albomyces laccase forms a plug that blocks this access.
Department of Chemistry, University of Joensuu, PO BOX 111, FIN-80101, Joensuu, Finland.
Nina
N
Hakulinen
Laura-Leena
LL
Kiiskinen
Kristiina
K
Kruus
Markku
M
Saloheimo
Arja
A
Paananen
Anu
A
Koivula
Juha
J
Rouvinen
D000595:Amino Acid Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D003300:Copper / Q000737:chemistry; D003302:Coprinus / Q000201:enzymology / Q000235:genetics; D018360:Crystallography, X-Ray; D042845:Laccase; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics; D010100:Oxygen / Q000737:chemistry; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D020037:Sordariales / Q000201:enzymology* / Q000235:genetics; D013045:Species Specificity; D055672:Static Electricity
D003300:Copper; D010088:Oxidoreductases; D042845:Laccase; D010100:Oxygen