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Publication Abstract from PubMed

Polyomavirus origins of replication contain multiple G(A/G)GGC sequences; the high affinity binding element for the viral initiator T-antigen (T-ag). The Site I regulatory region of Simian Virus 40, involved in the repression of transcription and the enhancement of DNA replication initiation, contains two GAGGC sequences arranged head-to-tail and separated by a 7 bp AT-rich sequence. We have solved a 3.2 A co-structure of the SV40 origin-binding domain (OBD) bound to Site I. We have also established that T-ag assembly on Site I is limited to the formation of a single hexamer. These observations have enabled an analyses of the role(s) of the OBDs bound to the Site I pentanucleotides in hexamer formation. Of interest, they reveal a correlation between the OBDs bound to Site I and a pair of OBD subunits in the previously described hexameric spiral structure. Based on these findings, we propose that spiral assembly is promoted by pentanucleotide pairs arranged in a head to tail manner. Finally, the possibility that "spiral-assembly " by OBD subunits may account for the heterogeneous distribution of pentanucleotides found in the origins of replication of polyomaviruses is discussed.

ANALYSIS OF THE CO-STRUCTURE OF THE SV40 T-ANTIGEN ORIGIN BINDING DOMAIN WITH SITE I REVEALS A CORRELATION BETWEEN GAGGC SPACING AND SPIRAL ASSEMBLY.,Meinke G, Phelan PJ, Harrison C, Bullock PA J Virol. 2012 Dec 26. PMID:23269808^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.