Method for increasing solubility of target protein using RNA-binding protein as fusion partner

Abstract

Disclosed is a method of producing a target protein having improved solubility and folding efficiency, characterized by expressing a target protein as a fusion protein using an RNA-binding protein as a fusion partner, and binding the fusion partner fused to the target protein to an RNA molecule. More particularly, the present invention discloses a method of producing a target protein having improved solubility and folding efficiency, comprising constructing an expression vector encoding a fusion protein using a target protein and an RNA-binding protein as a fusion partner of the target protein; constructing an expression vector expressing an RNA molecule capable of binding to the RNA-binding protein; and cotransforming a host cell with the expression vectors and then culturing the resulting transformant, wherein the expressed fusion protein binds to the overexpressed RNA molecule. The method of the present invention is very useful for production of proteins for medical and industrial applications.

1 . A method of producing a target protein having improved solubility and folding efficiency, comprising expressing a target protein as a fusion protein using an RNA-binding protein as a fusion partner, and binding the fusion partner fused to the target protein to an RNA molecule.  
     
     
         2 . The method as set forth in  claim 1 , wherein the fusion partner of the target protein is an RNA-binding protein or polypeptide selected from the group consisting of mRNA, tRNA, rRNA, nuclear RNA, viral RNA and ribo-polynucleotides prepared by genetic recombination techniques.  
     
     
         3 . The method as set forth in  claim 1 , wherein the fusion partner of the target protein is a protein selected from the group consisting of aminoacyl-tRNA synthetases, ribosomal proteins, mRNA-binding proteins, viral proteins having RNA-binding ability and proteins associated with cellular RNA processing and turnover, or a polypeptide corresponding to an RNA-binding region of the aforementioned proteins.  
     
     
         4 . The method as set forth in  claim 3 , wherein the fusion partner of the target protein is a protein selected from the group consisting of C5 protein of ribonuclease P (RNase P), Ffh protein of signal recognition particle, NP protein of influenza virus, ribosomal S1 protien, ribosomal S4 protein, ribosomal S17 protien,  E. coli  DbpA and  E. coli  Hsp15, or a polypeptide corresponding to an RNA-binding region of the aforementioned proteins.  
     
     
         5 . The method as set forth in  claim 1 , wherein the fusion partner of the target protein binds to an RNA molecule naturally present in cells, or an artificially co-expressed RNA molecule.  
     
     
         6 . The method as set forth in  claim 5 , wherein the RNA molecule is artificially overexpressed by constructing a vector expressing said RNA molecule and then introducing the vector into a host cell.  
     
     
         7 . The method as set forth in any of  claims 1  to  6 , wherein the method comprises the steps of: 
 1) constructing an expression vector encoding a fusion protein using a target protein and an RNA-binding protein as a fusion partner of the target protein;  
 2) constructing an expression vector expressing an RNA molecule capable of binding to the RNA-binding protein fused with the target protein; and  
 3) cotransforming a host cell with the expression vectors prepared in Steps 1 and 2.