Ensinger M J, Martin S A, Paoletti E, Moss B
Proc Natl Acad Sci U S A. 1975 Jul;72(7):2525-9. doi: 10.1073/pnas.72.7.2525.
RNA guanylyl and methyl transferases have been solubilized from vaccinia virus cores. The guanylyl transferase specifically adds a GMP residue to the 5'-terminus of unmethylated vaccinia virus mRNA to form the structures G(5')ppp(5')Gp- and G(5')ppp(5')Ap-. Studies with [alpha-32P]GTP and [beta, gamma-32P]GTP indicated that only the alpha-phosphate is transferred. In the presence of S-adenosylmethionine, the methyl transferases convert the blocked 5'-termini to m7G(5')ppp(5')Gmp- and m7G(5')ppp(5')Amp-. Similarly, the enzymes can modify synthetic poly(A) to form the structure m7G(5')ppp(5')Amp-.
RNA鸟苷酰转移酶和甲基转移酶已从痘苗病毒核心中溶解出来。鸟苷酰转移酶特异性地将一个GMP残基添加到未甲基化的痘苗病毒mRNA的5'-末端,形成G(5')ppp(5')Gp-和G(5')ppp(5')Ap-结构。用[α-32P]GTP和[β,γ-32P]GTP进行的研究表明,只有α-磷酸被转移。在S-腺苷甲硫氨酸存在的情况下,甲基转移酶将封闭的5'-末端转化为m7G(5')ppp(5')Gmp-和m7G(5')ppp(5')Amp-。同样,这些酶可以修饰合成的聚(A)以形成m7G(5')ppp(5')Amp-结构。