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Mushroom tyrosinase oxidizes tyrosine-rich sequences to allow selective protein functionalization.

ABSTRACT: We show that mushroom tyrosinase catalyzes the formation of reactive o-quinones on unstructured, tyrosine-rich sequences such as hemagglutinin (HA) tags (YPYDVPDYA). In the absence of exogenous nucleophiles and at low protein concentrations, the o-quinone decomposes with fragmentation of the HA tag. At higher protein concentrations (>5 mg?mL?¹), crosslinking is observed. Besthorn's reagent intercepts the o-quinone to give a characteristic pink complex that can be observed directly on a denaturing SDS-PAGE gel. Similar labeled species can be formed by using other nucleophiles such as Cy5-hydrazide. These reactions are selective for proteins bearing HA and other unstructured poly-tyrosine-containing tags and can be performed in lysates to create specifically tagged proteins.

SUBMITTER: Long MJ

PROVIDER: S-EPMC3516906 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

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Mushroom tyrosinase oxidizes tyrosine-rich sequences to allow selective protein functionalization.

Long Marcus J C MJ Hedstrom Lizbeth L

Chembiochem : a European journal of chemical biology 20120717 12

We show that mushroom tyrosinase catalyzes the formation of reactive o-quinones on unstructured, tyrosine-rich sequences such as hemagglutinin (HA) tags (YPYDVPDYA). In the absence of exogenous nucleophiles and at low protein concentrations, the o-quinone decomposes with fragmentation of the HA tag. At higher protein concentrations (>5 mg mL⁻¹), crosslinking is observed. Besthorn's reagent intercepts the o-quinone to give a characteristic pink complex that can be observed directly on a denaturin ...[more]

PMID: 22807021

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