Crystal structure of Middle East respiratory syndrome coronavirus helicase
MERS-CoV nsp13 is colored in cyan, EAV nsp10 is colored in blue and Upf1 is colored in magenta. Secondary structure elements or subdomains of MERS-CoV nsp13 are labeled with regular font, secondary structure elements of EAV nsp10 and Upf1 helicase are labeled with italic font. (A) The structure of CH of Upf1 (PDB ID: 2XZL) is superimposed with the CH of MERS-CoV nsp13 (PDB ID: 5WWP). Three zinc atoms of each CH domain are indicated. (B) The structure of ZBD of EAV nsp10 (PDB ID: 4N0N) is superimposed to the CH domain of MERS-CoV nsp13. Three zinc atoms of each CH or ZBD are indicated (italic fonts). (C) Structure based multiple sequence alignment of CH/ZBD domains of Upf1 like helicases, including helicases from human CoVs (MERS-CoV, SARS-CoV, HKU1-CoV, OC43-CoV, NL63-CoV and 229E-CoV), EAV nsp10 and Upf1 helicase. The sequences were aligned using MUSCLE software . Cys/His residues involved in the coordination of Zn1, Zn2 and Zn3 are colored with magenta, blue and cyan, respectively. The secondary structure elements are aligned to the sequence. (D) Superimposition of MERS-CoV nsp13 and Upf1. (E) Superimposition of MERS-CoV nsp13 and EAV nsp10. MERS-CoV nsp13 is the reference structure with the same orientation as in Fig 2A. The subdomains of the helicases are labeled (regular fonts for MERS-CoV nsp13, italic fonts for Upf1 or EAV nsp10).