Anabaena sp DyP-type peroxidase is a tetramer consisting of two asymmetric dimers

作者：Yoshida Toru; Ogola Henry Joseph Oduor; Amano Yoshimi; Hisabori Toru; Ashida Hiroyuki; Sawa Yoshihiro; Tsuge Hideaki^*; Sugano Yasushi^*

来源：Proteins: Structure, Function, and Genetics , 2016, 84(1): 31-42.

DOI：10.1002/prot.24952

• DyP-type peroxidase
• AnaPX
• structural asymmetry
• structure-based sequence alignment
• thermostability

DyP-type peroxidases are a newly discovered family of heme peroxidases distributed from prokaryotes to eukaryotes. Recently, using a structure-based sequence alignment, we proposed the new classes, P, I and V, as substitutes for classes A, B, C, and D [Arch Biochem Biophys 2015;574:49-55]. Although many class V enzymes from eukaryotes have been characterized, only two from prokaryotes have been reported. Here, we show the crystal structure of one of these two enzymes, Anabaena sp. DyP-type peroxidase (AnaPX). AnaPX is tetramer formed from Cys224-Cys224 disulfide-linked dimers. The tetramer of wild-type AnaPX was stable at all salt concentrations tested. In contrast, the C224A mutant showed salt concentration-dependent oligomeric states: in 600 mM NaCl, it maintained a tetrameric structure, whereas in the absence of salt, it dissociated into monomers, leading to a reduction in thermostability. Although the tetramer exhibits non-crystallographic, 2-fold symmetry in the asymmetric unit, two subunits forming the Cys224-Cys224 disulfide-linked dimer are related by 165 degrees rotation. This asymmetry creates an opening to cavities facing the inside of the tetramer, providing a pathway for hydrogen peroxide access. Finally, a phylogenetic analysis using structure-based sequence alignments showed that class V enzymes from prokaryotes, including AnaPX, are phylogenetically closely related to class V enzymes from eukaryotes. Proteins 2016; 84:31-42.

• 出版日期2016-1