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The in vitro refolding of hen egg-white lysozyme is studied in the presence of various osmolytes. Proline is found to prevent aggregation during protein refolding. However, other osmolytes used in this study fail to exhibit a similar property. Experimental evidence suggests that proline inhibits protein aggregation by binding to folding intermediate(s) and(More)
Arginine (Arg) has been used for recognizing negatively charged biological molecules, cell penetration, and oligosaccharide mass signal enhancement. The versatility of Arg has inspired the need to develop Arg analogs and to research the structural effects of incorporating Arg analogs. Accordingly, we investigated the effect of Arg side chain length on helix(More)
Helix-coil equilibrium studies are important for understanding helix formation in protein folding, and for helical foldamer design. The quantitative description of a helix using statistical mechanical models is based on experimentally derived helix propensities and the assumption that helix propensity is position-independent. To investigate this assumption,(More)
Ion pairing interactions between oppositely charged amino acids are important for protein structure stability. Despite the apparent electrostatic nature of these interactions, the charged amino acids Lys, Arg, Glu, and Asp have a different number of hydrophobic methylenes linking the charged functionality to the backbone. To investigate the effect of Glu(More)
β-Sheets are one of the fundamental three-dimensional building blocks for protein structures. Oppositely charged amino acids are frequently observed directly across one another in antiparallel sheet structures, suggesting the importance of cross-strand ion pairing interactions. Despite the apparent electrostatic nature of ion pairing interactions, the(More)
The charge-containing hydrophilic functionalities of encoded charged amino acids are linked to the backbone via different numbers of hydrophobic methylenes, despite the apparent electrostatic nature of protein ion pairing interactions. To investigate the effect of side chain length of guanidinium- and carboxylate-containing residues on ion pairing(More)
β-Sheets have been implicated in various neurological disorders, and ∼20% of protein residues adopt a sheet conformation. Therefore, studies on the structural origin of sheet stability can provide fundamental knowledge with potential biomedical applications. Oppositely charged amino acids are frequently observed across one another in antiparallel β-sheets.(More)
The effect of organic acids on the aggregation of protein(s) during rapid refolding is studied. Using egg white lysozyme, it is observed that acetic acid not only prevents aggregation, but also aids the protein to refold back to its native, biologically active state. In contrast, formic acid, propionic acid and butyric acid fail to exhibit this property.(More)
The cardiotoxin analogue III (CTX III), isolated from the Taiwan cobra (Naja naja atra) venom, is a sixty-amino acid, all beta-sheet protein. We report the direct expression of CTX III from its synthetic gene as inclusion bodies in Escherichia coli. The yield of the expressed protein is about 40 mg/liter of the culture. CTX III trapped as inclusion bodies(More)