8pw4

Structural highlights

Function

NP_BPPH2 Histone-like nucleoprotein that binds to the viral dsDNA and responsible for wrapping and compacting the viral DNA about 4-fold. Forms a nucleoprotein complex in which the DNA adopts a right-handed toroidal conformation winding around a protein core. Binds ito most, if not all, the viral genome, although with different affinity, the highest one corresponding to the genome ends. The formation of the nucleoprotein complex at the genome ends, activates the initiation of viral DNA replication. The binding of p6 would recruit the complex formed by the TP and the DNA polymerase to the origin. Protein p6 also represses early transcription from promoter C2, and, together with protein p4, represses transcription from promoters A2b and A2c and activates late transcription from promoter A3. Protein p6 is therefore involved in the early to late transcription switch. The formation of the nucleoprotein complex at the right end of the phage genome where the early promoter C2 is located affects local topology, which may contribute to the promoter repression.^{[1] [2] [3] [4] [5]}

References

1. ↑ Camacho A, Salas M. Repression of bacteriophage phi 29 early promoter C2 by viral protein p6 is due to impairment of closed complex. J Biol Chem. 2001 Aug 3;276(31):28927-32. PMID:11384991 doi:10.1074/jbc.M103738200
2. ↑ Calles B, Salas M, Rojo F. The phi29 transcriptional regulator contacts the nucleoid protein p6 to organize a repression complex. EMBO J. 2002 Nov 15;21(22):6185-94. doi: 10.1093/emboj/cdf623. PMID:12426390 doi:http://dx.doi.org/10.1093/emboj/cdf623
3. ↑ González-Huici V, Salas M, Hermoso JM. Genome wide, supercoiling-dependent in vivo binding of a viral protein involved in DNA replication and transcriptional control. Nucleic Acids Res. 2004 Apr 26;32(8):2306-14. PMID:15118076 doi:10.1093/nar/gkh565
4. ↑ González-Huici V, Alcorlo M, Salas M, Hermoso JM. Binding of phage Phi29 architectural protein p6 to the viral genome: evidence for topological restriction of the phage linear DNA. Nucleic Acids Res. 2004 Jul 1;32(11):3493-502. PMID:15247336 doi:10.1093/nar/gkh668
5. ↑ Serrano M, Salas M, Hermoso JM. A novel nucleoprotein complex at a replication origin. Science. 1990 May 25;248(4958):1012-6. PMID:2111580 doi:10.1126/science.2111580