The invention discloses a PLAG-Tn5
fusion protein as well as a preparation method and application thereof. According to the
fusion protein, dominant
immunoglobulin binding structural domains of
Protein L,
Protein A and
Protein G are functionally fused with Tn5
transposase, so that IgG antibodies of various
genus sources such as mice, rats and rabbits can be efficiently recognized in a broad-spectrum manner, and the problem of existing CUTamp is thoroughly solved; and the problems of poor
antibody compatibility, need of using a second
antibody, low
signal-to-
noise ratio and the like caused by insufficient PA / PG-Tn5 affinity in a Tag technology are solved. The invention also provides a low-cost and high-yield preparation method of the
fusion protein and a matched preparation process of low-cost and high-efficiency carboxyl
nucleic acid purification magnetic beads. The fusion
protein and the magnetic beads jointly form the CUTamp which is low in cost, high in efficiency and high in sensitivity. A Tag
research system is especially suitable for
protein-
DNA interaction research of precious low-amount clinical samples such as primary cells and PBMC, and popularization and clinical transformation of the technology are powerfully promoted.