tailieunhanh - Báo cáo khoa học: Crystal structure of the shutoff and exonuclease protein from the oncogenic Kaposi’s sarcoma-associated herpesvirus

The Kaposi’s sarcoma-associated herpesvirus protein SOX (shut off and exonuclease) and its Epstein–Barr virus homolog, BGLF5, are active during the early lytic phase and belong to the alkaline nuclease family. Both proteins have been shown to be bifunctional, being responsible for DNA maturation as well as host shutoff at the mRNA level. | Crystal structure of the shutoff and exonuclease protein from the oncogenic Kaposi s sarcoma-associated herpesvirus Sue-Li Dahlroth1 2 Daniel Gurmu1 2 Juergen Haas3 4 Heidi Erlandsen5 and Par Nordlund1 1 MedicalBiochemistry and Biophysics Karolinska Institutet Stockholm Sweden 2 Department of Biochemistry and Biophysics Arrhenius Laboratories for NaturalSciences Stockholm University Sweden 3 Max von Pettenkofer Institut Ludvig Maximillian Universitat Munchen Germany 4 Division of Pathway Medicine University of Edinburgh UK 5 University of Alabama at Birmingham Schoolof Dentistry Institute of OralHealth Research AL USA Keywords alkaline exonuclease KSHV SOX structure virus Correspondence P. Nordlund MedicalBiochemistry and Biophysics Karolinska Institutet Scheeles Vag 2 SE-171 77 Stockholm Sweden Fax 46 852486850 Tel 46 852486860 E-mail Database The coordinates and structure factor have been deposited in the Protein Data Bank under the accession number 3FHD. These authors contributed equally to this work. The Kaposi s sarcoma-associated herpesvirus protein SOX shut off and exonuclease and its Epstein-Barr virus homolog BGLF5 are active during the early lytic phase and belong to the alkaline nuclease family. Both proteins have been shown to be bifunctional being responsible for DNA maturation as well as host shutoff at the mRNA level. We present the crystal structure of SOX determined at A resolution. By modeling DNA binding we have identified catalytic residues that explain the preferred 5 -exonuclease activity of the alkaline nucleases. The presence of a crevice suitable for binding duplex DNA supports a role for herpes alkaline nucleases in recombination events preceding packaging of viral DNA. Direct interaction with dsDNA is supported by oligonucleotide binding data. Mutations specifically affecting host shutoff map to a surface region of the N-terminal domain implying an essential role in protein-protein interactions and link the RNase .