The crystal structure of an extracellular catechol oxidase from the ascomycete fungus Aspergillus oryzae

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• 作者：Nina Hakulinen (1)
  Chiara Gasparetti (1) (2)
  Heidi Kaljunen (1) (3)
  Kristiina Kruus (2)
  Juha Rouvinen (1)
  
• 关键词：Type3 copper enzymes ; Catechol oxidase ; Tyrosinase ; Binuclear copper site ; X ; ray crystallography
• 刊名：Journal of Biological Inorganic Chemistry
• 出版年：2013
• 出版时间：December 2013
• 年：2013
• 卷：18
• 期：8
• 页码：917-929
• 全文大小：
• 作者单位：Nina Hakulinen (1)
  Chiara Gasparetti (1) (2)
  Heidi Kaljunen (1) (3)
  Kristiina Kruus (2)
  Juha Rouvinen (1)
  
  1. Department of Chemistry, University of Eastern Finland, Joensuu Campus, PO Box 111, 80101, Joensuu, Finland
  2. VTT Technical Research Center of Finland, PO Box 1000, 02044, Espoo, Finland
  3. EMBL Hamburg c/o DESY, Notkestrae 85, 22603, Hamburg, Germany
  
• ISSN：1432-1327

文摘

Catechol oxidases (EC 1.10.3.1) catalyse the oxidation of o-diphenols to their corresponding o-quinones. These oxidases contain two copper ions (CuA and CuB) within the so-called coupled type3 copper site as found in tyrosinases (EC 1.14.18.1) and haemocyanins. The crystal structures of a limited number of bacterial and fungal tyrosinases and plant catechol oxidases have been solved. In this study, we present the first crystal structure of a fungal catechol oxidase from Aspergillus oryzae (AoCO4) at 2.5- resolution. AoCO4 belongs to the newly discovered family of short-tyrosinases, which are distinct from other tyrosinases and catechol oxidases because of their lack of the conserved C-terminal domain and differences in the histidine pattern for CuA. The sequence identity of AoCO4 with other structurally known enzymes is low (less than 30%), and the crystal structure of AoCO4 diverges from that of enzymes belonging to the conventional tyrosinase family in several ways, particularly around the central helical core region. A diatomic oxygen moiety was identified as a bridging molecule between the two copper ions CuA and CuB separated by a distance of 4.2.3 . The UV/vis absorption spectrum of AoCO4 exhibits a distinct maximum of absorbance at 350nm, which has been reported to be typical of the oxy form of type3 copper enzymes.