title: N-terminal domains of native multidomain proteins have the potential to assist de novo folding of their downstream domains in vivo by acting as solubility enhancers.
abstract: The fusion of soluble partner to the N terminus of aggregation-prone polypeptide has been popularly used to overcome the formation of inclusion bodies in the E. coli cytosol. The chaperone-like functions of the upstream fusion partner in the artificial multidomain proteins could occur in de novo folding of native multidomain proteins. Here, we show that the N-terminal domains of three E. coli multidomain proteins such as lysyl-tRNA synthetase, threonyl-tRNA synthetase, and aconitase are potent solubility enhancers for various C-terminal heterologous proteins. The results suggest that the N-terminal domains could act as solubility enhancers for the folding of their authentic C-terminal domains in vivo. Tandem repeat of N-terminal domain or insertion of aspartic residues at the C terminus of the N-terminal domain also increased the solubility of fusion proteins, suggesting that the solubilizing ability correlates with the size and charge of N-terminal domains. The solubilizing ability of N-terminal domains would contribute to the autonomous folding of multidomain proteins in vivo, and based on these results, we propose a model of how N-terminal domains solubilize their downstream domains.
authors: Department of Biotechnology, College of Engineering, Yonsei University, Seodaemun-Gu, Seoul 120-749, Korea.
authors: Chul Woo
authors: CW
authors: Kim
authors: Kyoung Sim
authors: KS
authors: Han
authors: Ki-Sun
authors: KS
authors: Ryu
authors: Byung Hee
authors: BH
authors: Kim
authors: Kyun-Hwan
authors: KH
authors: Kim
authors: Seong Il
authors: SI
authors: Choi
authors: Baik L
authors: BL
authors: Seong
mesh_terms: D000154:Aconitate Hydratase / Q000737:chemistry; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008250:Lysine-tRNA Ligase / Q000737:chemistry; D008958:Models, Molecular; D017510:Protein Folding; D012995:Solubility; D020080:Tandem Repeat Sequences; D013914:Threonine-tRNA Ligase / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; D000154:Aconitate Hydratase; D013914:Threonine-tRNA Ligase; D008250:Lysine-tRNA Ligase