title: Importance of polypeptide chain length for the correct local folding of a β-sheet protein.
abstract: Equine β-lactoglobulin is a 162-residue β-sheet protein. A partially folded form of equine β-lactoglobulin contains a β-hairpin and an α-helix. The β-hairpin converts into non-native α-helices at temperatures <0°C. CHIBL, a truncated equine β-lactoglobulin (residues 88-142), contains the low-temperature α-helical structure even at room temperature, indicating that the interactions responsible for the stability of the β-hairpin reside in non-CHIBL residues. For the study reported herein, we characterized two truncated mutants and their leucine103 → proline103 variants to identify residues that stabilize the β-hairpin. The dependence of their circular dichroism spectra on chloride ion concentration and temperature revealed that the ability to transition from the non-native α-helices to the β-hairpin depends on the polypeptide chain length and improves as the chain length increases despite the apparent absence of any ordered structure in the extended sequences.
authors: Department of Bioinformatics, Soka University, 1‐236 Tangi-cho, Hachioji, Tokyo 192‐8577, Japan.
authors: Mio
authors: M
authors: Yamamoto
authors: Kanako
authors: K
authors: Nakagawa
authors: Masamichi
authors: M
authors: Ikeguchi
mesh_terms: D000818:Animals; D002712:Chlorides / Q000737:chemistry; D002942:Circular Dichroism; D006736:Horses; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013696:Temperature
chemical_list: D002712:Chlorides; D007782:Lactoglobulins