Structure of laccase fromStreptomyces coelicolorafter soaking with potassium hexacyanoferrate and at an improved resolution of 2.3 Å

Abstract

The paper reports the structure of the small laccase from Streptomyces coelicolor determined from a crystal soaked with potassium hexacyanoferrate [K 4 Fe(CN) 6 ]. The decolorization of the natively blue crystal observed upon soaking indicates the reduction of the enzyme in the crystal. The ligand binds between laccase molecules and stabilizes the crystal. The increased diffraction limit of the diffraction data collected from this crystal enabled the refinement of the small laccase structure at 2.3 Å resolution, which is the highest resolution obtained to date.

The Rise of Radicals in Bioinorganic Chemistry

“…[46b, 82] Copper centers are shown as spheres; Tyr/Trp clusters are shown in red (5-Å ET distance) and green (7.5 Å). The type 1 Cu centers are at the top of the structure; the TNC Cu centers are in the midlevel region.…”

“…ATCC 39116 (PDB ID 3T9W); [40a] (b) Streptomyces viridosporus (3TAS); [40a] (c) Streptomyces viridochromogenes (4N8U); (d) Streptomyces sviceus (4M3H); [42] (e) Streptomyces lividans (4GYB); (f) Streptomyces coelicolor (3KW8); [46b, 82] (g) Nitrosomonas europaea (3G5W); [44] (h) Arthrobacter sp. FB24 (3GDC).…”

“… Polypeptide ribbon diagram of the small 2dMCO from Streptomycese coelicolor (PDB ID 3 KW8) ,. Copper centers are shown as spheres; Tyr/Trp clusters are shown in red (5‐Å ET distance) and green (7.5 Å).…”

“… Polypeptide ribbon diagrams of copper two‐domain multicopper oxidases (2dMCO) highlighting locations of the copper centers (spheres) and Tyr/Trp chains with 5‐Å (red) ET cutoff distances: (a) Amycolatopsis sp . ATCC 39116 (PDB ID 3T9W); (b) Streptomyces viridosporus (3TAS); (c) Streptomyces viridochromogenes (4N8U); (d) Streptomyces sviceus (4M3H); (e) Streptomyces lividans (4GYB); (f) Streptomyces coelicolor (31 KW8);, (g) Nitrosomonas europaea (3G5W); (h) Arthrobacter sp . FB24 (3GDC).…”

Does Tyrosine Protect S. Coelicolor Laccase from Oxidative Degradation?

“…[14][15][16] The powerfully oxidizing copper enzyme is a homotrimer in which each monomer is comprised of two cupredoxin structural domains ( Figure 1A). [17][18][19][20] Tyr108, which may function in a protective role, is conserved among all two-domain laccases, as well as in the mammalian protein ceruloplasmin. 7 As Tyr108 is buried in the protein interior, reduction of a radical intermediate at this site would require intraprotein electron transfer from CuT1 or hole hopping though Trp/Tyr chains to a reductant at the surface.…”