Sweeping Away Protein Aggregation with Entropic Bristles: Intrinsically Disordered Protein Fusions Enhance Soluble Expression

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• 作者：Aaron A. Santner ; Carrie H. Croy ; Farha H. Vasanwala ; Vladimir N. Uversky ; Ya-Yue J. Van ; A. Keith Dunker
• 刊名：Biochemistry
• 出版年：2012
• 出版时间：September 18, 2012
• 年：2012
• 卷：51
• 期：37
• 页码：7250-7262
• 全文大小：477K
• 年卷期：v.51,no.37(September 18, 2012)
• ISSN：1520-4995

文摘

Intrinsically disordered, highly charged protein sequences act as entropic bristles (EBs), which, when translationally fused to partner proteins, serve as effective solubilizers by creating both a large favorable surface area for water interactions and large excluded volumes around the partner. By extending away from the partner and sweeping out large molecules, EBs can allow the target protein to fold free from interference. Using both naturally occurring and artificial polypeptides, we demonstrate the successful implementation of intrinsically disordered fusions as protein solubilizers. The artificial fusions discussed herein have a low level of sequence complexity and a high net charge but are diversified by means of distinctive amino acid compositions and lengths. Using 6xHis fusions as controls, soluble protein expression enhancements from 65% (EB60A) to 100% (EB250) were observed for a 20-protein portfolio. Additionally, these EBs were able to more effectively solubilize targets compared to frequently used fusions such as maltose-binding protein, glutathione S-transferase, thioredoxin, and N utilization substance A. Finally, although these EBs possess very distinct physiochemical properties, they did not perturb the structure, conformational stability, or function of the green fluorescent protein or the glutathione S-transferase protein. This work thus illustrates the successful de novo design of intrinsically disordered fusions and presents a promising technology and complementary resource for researchers attempting to solubilize recalcitrant proteins.