Heterologous gene expression using self-assembled supra-molecules with high affinity for HSP70 chaperone

Ji Young Ahn, Hyung Choi, Yang Hoon Kim, Kyung Yeon Han, Jin Seung Park, Sung Sik Han, Jeewon Lee

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


Contrary to the results of direct expression, various human proteins (ferritin light-chain, epithermal growth factor, interleukin-2, prepro-ghrelin, deletion mutants of glutamate decarboxylase and arginine deiminase, and mini-proinsulin) were all soluble in Escherichia coli cytoplasm when expressed with the N-terminus fusion of ferritin heavy-chain (FTN-H). Through systematic investigations, we have found that a specific peptide motif within FTN-H has a high affinity to HSP70 chaperone DnaK, and that the peptide motif was composed of a hydrophobic core of three residues (Ile, Phe and Leu) and two flanking regions enriched with polar residues (Gly, Gln and Arg). It was also observed that all the recombinant proteins expressed with the fusion of FTN-H formed spherical nanoparticles with diameters of 10-15 nm, as confirmed by the transmission electron microscopy image. The protein nanoparticles are non-covalently cross-linked supra-molecules formed by the self-assembly function of FTN-H. Upon the formation of the supra-molecule, its size is likely to be limited by the assembly properties of FTN-H, thereby keeping the self-assembled particles soluble. This study reports on the dual function of FTN-H for fusion expression and solubility enhancement of heterologous proteins: (i) high-affinity interaction with DnaK and (ii) formation of self-assembled supra-molecules with limited and constant sizes, thereby avoiding the undesirable formation of insoluble macro-aggregates of heterologous proteins.

Original languageEnglish
Pages (from-to)3751-3762
Number of pages12
JournalNucleic acids research
Issue number12
Publication statusPublished - 2005

Bibliographical note

Funding Information:
This work was supported by Korea Research Foundation Grants (KRF-2002-041-D00196 and KRF-2004-005-D00057) and Korea Science and Engineering Foundation Grant (R01-2005-000-10355-0). This work was also supported by Microbial Genomics & Applications Center Grant (Microbial Genomics and Applications R & D Program). Funding to pay the Open Access publication charges for this article was provided by R01-2005-000-10355-0.

ASJC Scopus subject areas

  • Genetics


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