4kw3
From Proteopedia
Crystal structure of the non-structural protein 1 N-terminal origin-recognition/nickase domain from the emerging human bocavirus
Structural highlights
FunctionNS1_HBOC1 Multifunctional protein which displays endonuclease and helicase activities required for initiating and directing viral DNA replication. Also plays a role in viral packaging and transactivation of several promoters. Binds site-specifically to 2-3 approximate tandem copies within the origins of replication (Ori), unwinds this hairpin region and nicks one DNA strand thereby initiating the rolling circle replication (RCR). Becomes covalently attached to the 5' end of the nick and provides a 3'OH for priming DNA synthesis. The helicase activity unwinds DNA in a 3'-5' direction on the longer strand. Participates in the transcriptional regulation of several promoters.[UniProtKB:P03134] Publication Abstract from PubMedHuman bocavirus is a newly identified, globally prevalent, parvovirus that is associated with respiratory infection in infant and young children. Parvoviruses encode a large non-structural protein 1 (NS1) that is essential for replication of the viral single-stranded DNA genome and DNA packaging and may play versatile roles in virus:host interaction. Here we report the structure of the human parvovirus NS1 N-terminal domain, the first for any autonomous parvovirus. The structure shows an overall fold that is canonical to the histidine-hydrophobic-histidine superfamily of nucleases, which integrates two distinct DNA-binding sites: a positively charged region mediated by a surface hairpin (residues 190-198) that is responsible for recognition of the viral origin of replication of the double-stranded DNA nature; and the nickase active site that binds to the single-stranded DNA substrate for site-specific cleavage. The structure reveals an acidic-residue-rich sub-domain that is present in bocavirus NS1 proteins but not in the NS1 orthologs in erythrovirus or dependovirus, which may mediate bocavirus-specific interaction with DNA or potential host factors. These results provide insights into recognition of the origin of replication and nicking of DNA during bocavirus genome replication. Mapping of variable amino acid residues of NS1s from four HBoV species onto the structure shows a scattered pattern, but the origin-recognition site and the nuclease active site are invariable, suggesting potential targets for antivirals against this clade of highly diverse human viruses. Structure of the NS1 protein N-terminal origin-recognition/nickase domain from the emerging human bocavirus.,Tewary SK, Zhao H, Shen W, Qiu J, Tang L J Virol. 2013 Aug 21. PMID:23966383[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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