Structural highlights
Function
MCE_VACCW Displays methyltransferase, positive regulation of the poly(A) polymerase and transcription elongation activities. Involved in the modification of both mRNA ends and in intermediate and late gene positive transcription elongation. At the mRNAs 5' end, methylates the ribose 2' OH group of the first transcribed nucleotide, thereby producing a 2'-O-methylpurine cap. At the 3' end, functions as a processivity factor which stimulates the activity of the viral poly(A) polymerase VP55 that creates mRNA's poly(A) tail. In the presence of VP39, VP55 does not dissociate from the RNA allowing tail elongation to around 250 adenylates.[1] [2] [3]
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 PubMed
Vaccinia virus protein VP55 translocates continuously with respect to single-stranded nucleic acid while extending its 3'end. Here, all key sites of polymerase-primer interaction were identified, demonstrating the wrapping or looping of polyadenylation primer around the polymerase during translocation. Side-chain substitutions at one of the sites indicated its requirement for tail extension beyond approximately 12 nucleotides in length, and conformational changes observed upon oligonucleotide binding suggested allosteric connectivity during translocation. Conformational changes in VP39 upon VP55 binding suggested that, within the VP55-VP39 complex, VP39's mRNA 5' cap binding site closes. The crystallographic structure showed a PAPase catalytic center without side-chain substitutions, possessing two metal ions and with all known reactive and catalytic groups represented, fitting a classical two-metal ion mechanism for phosphoryl transfer.
Polymerase translocation with respect to single-stranded nucleic acid: looping or wrapping of primer around a poly(A) polymerase.,Li C, Li H, Zhou S, Sun E, Yoshizawa J, Poulos TL, Gershon PD Structure. 2009 May 13;17(5):680-9. PMID:19446524[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Schnierle BS, Gershon PD, Moss B. Cap-specific mRNA (nucleoside-O2'-)-methyltransferase and poly(A) polymerase stimulatory activities of vaccinia virus are mediated by a single protein. Proc Natl Acad Sci U S A. 1992 Apr 1;89(7):2897-901. PMID:1313572
- ↑ Gershon PD, Ahn BY, Garfield M, Moss B. Poly(A) polymerase and a dissociable polyadenylation stimulatory factor encoded by vaccinia virus. Cell. 1991 Sep 20;66(6):1269-78. PMID:1670500
- ↑ Latner DR, Thompson JM, Gershon PD, Storrs C, Condit RC. The positive transcription elongation factor activity of the vaccinia virus J3 protein is independent from its (nucleoside-2'-O-) methyltransferase and poly(A) polymerase stimulatory functions. Virology. 2002 Sep 15;301(1):64-80. PMID:12359447
- ↑ Li C, Li H, Zhou S, Sun E, Yoshizawa J, Poulos TL, Gershon PD. Polymerase translocation with respect to single-stranded nucleic acid: looping or wrapping of primer around a poly(A) polymerase. Structure. 2009 May 13;17(5):680-9. PMID:19446524 doi:10.1016/j.str.2009.03.012
