title: Crystal structure of 2A proteinase from hand, foot and mouth disease virus.
abstract: EV71 is responsible for several epidemics worldwide; however, the effective antiviral drug is unavailable to date. The 2A proteinase (2A(pro)) of EV71 presents a promising drug target due to its multiple roles in virus replication, inhibition of host protein synthesis and evasion of innate immunity. We determined the crystal structure of EV71 2A(pro) at 1.85Å resolution, revealing that the proteinase maintains a chymotrypsin-like fold. The active site is composed of the catalytic triads C110A, H21 and D39 with the geometry similar to that in other picornaviral 2A(pro), 3C(pro) and serine proteinases. The cI-to-eI2 loop at the N-terminal domain of EV71 2A(pro) adopts a highly stable conformation and contributes to the hydrophilic surface property, which are strikingly different in HRV2 2A(pro) but are similar in CVB4 2A(pro). We identified a hydrophobic motif "LLWL" followed by an acidic motif "DEE" at the C-terminus of EV71 2A(pro). The "LLWL" motif is folded into the β-turn structure that is essential for the positioning of the acidic motif. Our structural and mutagenesis study demonstrated that both the negative charging and the correct positioning of the C-terminus are essential for EV71 replication. Deletion of the "LLWL" motif abrogated the proteolytic activity, indicating that the motif is critical for maintaining the active proteinase conformation. Our findings provide the structural and functional insights into EV71 2A(pro) and establish a framework for structure-based inhibitor design.
authors: MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 9 Dong Dan San Tiao, Beijing 100730, People's Republic of China.
authors: Zhixia
authors: Z
authors: Mu
authors: Bei
authors: B
authors: Wang
authors: Xiaoyu
authors: X
authors: Zhang
authors: Xiaopan
authors: X
authors: Gao
authors: Bo
authors: B
authors: Qin
authors: Zhendong
authors: Z
authors: Zhao
authors: Sheng
authors: S
authors: Cui
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D003546:Cysteine Endopeptidases / Q000737:chemistry*; D029544:Foot-and-Mouth Disease Virus / Q000201:enzymology* / Q000235:genetics; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry*; D014779:Virus Replication
chemical_list: D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C057400:picornain 2A, Picornavirus
keywords: chymotrypsin-like proteinase; enterovirus 71; innate immunity evasion; virus replication; zinc binding site