Purification, crystallization and preliminary crystallographic analysis of avian infectious bronchitis virus nsp3 ADRP domain

Wei, Lei; Chen, Cheng; Zhao, Qi; Li, Chun; Cong, Le; Xu, Xiaoling; Ma, Yanlin; Liao, Ming; Xu, Yuanyuan; Rao, Zihe

Avian infectious bronchitis virus (IBV) encodes 15 nonstructural proteins (nsps) which play crucial roles in RNA transcription and genome replication. One of them, nsp3, contains an ADRP (adenosine diphosphate-ribose-1′-phosphatase) domain which was revealed in recent studies to have ADP-ribose-1′-monophos­phatase (Appr-1′-pase) activity. Appr-1′-pase catalyzes the conversion of ADP-ribose-1′-monophosphate (Appr-1′-p) to ADP-ribose in the tRNA-splicing pathway. The gene segment encoding the IBV nsp3 ADRP domain has been cloned and expressed in Escherichia coli. The protein has been crystallized and the crystals diffracted to 1.8 Å resolution. They belonged to space group P1, with unit-cell parameters a = 41.1, b = 43.2, c = 48.9 Å, α = 78.0, β = 80.0, γ = 73.6°. Each asymmetric unit contains two molecules.