2w4b
From Proteopedia
Epstein-Barr virus alkaline nuclease D203S mutant
Structural highlights
FunctionAN_EBVB9 Displays DNase activity required for viral genome processing in the nucleus. Plays a role in processing non linear or branched viral DNA intermediates and in capsid egress from the host nucleus. Exhibits endonuclease and exonuclease activities and accepts both double-stranded and single-stranded DNA as substrate. Exonuclease digestion of DNA is in the 5'-> 3' direction and the products are 5'-monophosphate nucleosides. Also acts as a cytoplasmic RNA endonuclease that induces degradation of the majority of the cellular messenger RNAs during lytic infection. The resulting inhibition of cellular protein synthesis serves to ensure maximal viral gene expression and evasion from host immune response.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEpstein-Barr virus, a double-stranded DNA (dsDNA) virus, is a major human pathogen from the herpesvirus family. The nuclease is one of the lytic cycle proteins required for successful viral replication. In addition to the previously described endonuclease and exonuclease activities on single-stranded DNA and dsDNA substrates, we observed an RNase activity for Epstein-Barr virus nuclease in the presence of Mn(2+), giving a possible explanation for its role in host mRNA degradation. Its crystal structure shows a catalytic core of the D-(D/E)XK nuclease superfamily closely related to the exonuclease from bacteriophage lambda with a bridge across the active-site canyon. This bridge may reduce endonuclease activity, ensure processivity or play a role in strand separation of dsDNA substrates. As the DNA strand that is subject to cleavage is likely to make a sharp turn in front of the bridge, endonuclease activity on single-stranded DNA stretches appears to be possible, explaining the cleavage of circular substrates. A bridge crosses the active-site canyon of the Epstein-Barr virus nuclease with DNase and RNase activities.,Buisson M, Geoui T, Flot D, Tarbouriech N, Ressing ME, Wiertz EJ, Burmeister WP J Mol Biol. 2009 Aug 28;391(4):717-28. Epub 2009 Jun 16. PMID:19538972[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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