Crystallization and preliminary X-ray crystallographic analysis of latent isoform PPO4 mushroom (Agaricus bisporus)tyrosinase

Abstract

Tyrosinase exhibits catalytic activity for theortho-hydroxylation of monophenols to diphenols as well as their subsequent oxidation to quinones. Owing to polymerization of these quinones, brown-coloured high-molecular-weight compounds called melanins are generated. The latent precursor form of polyphenol oxidase 4, one of the six tyrosinase isoforms fromAgaricus bisporus, was purified to homogeneity and crystallized. The obtained crystals belonged to space groupC121 (two molecules per asymmetric unit) and diffracted to 2.78 Å resolution. The protein only formed crystals under low-salt conditions using the 6-tungstotellurate(VI) salt Na6[TeW6O24]·22H2O as a co-crystallization agent.