Protective effect of small amounts of sodium dodecyl sulfate on the helical structure of bovine serum albumin in thermal denaturation

• Published in: Journal of colloid and interface science Vol. 257; no. 1; pp. 41 - 46
• Main Authors: Moriyama, Yoshiko, Kawasaka, Yoshie, Takeda, Kunio
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 2003; Elsevier
• Subjects: Amphiphilic material; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Bovine serum albumin; Cattle; Chemistry; Circular Dichroism; Cross-linking function; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General and physical chemistry; General aspects, investigation methods; Hot Temperature; Protective effect on protein structure; Protein Denaturation - drug effects; Protein Renaturation - drug effects; Protein structure; Protein Structure, Secondary; Proteins; Secondary structure; Serum Albumin, Bovine - chemistry; Serum Albumin, Bovine - metabolism; Sodium dodecyl sulfate; Sodium Dodecyl Sulfate - metabolism; Sodium Dodecyl Sulfate - pharmacology; Sulfuric Acid Esters; Surface physical chemistry; Surface-Active Agents - metabolism; Surface-Active Agents - pharmacology; Surface-active agents: properties; Surfactant; Thermal denaturation; Sodium dodecyl sulfate; Bovine serum albumin; Amphiphilic material; Cross-linking function; Thermal denaturation; Secondary structure; Protective effect on protein structure; Surfactant; Protein structure; Circular dichroism; Molecular structure; Preservation agent; Sodium compound; Serum albumin; Experimental study; Protein; Lauryl sulfate; Anionic surfactant; Concentration effect; Helical structure; Bovine serum albuins Thermal denaturation
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/S0021-9797(02)00017-6

In the presence of sodium dodecyl sulfate (SDS), the secondary structure of bovine serum albumin (BSA) was almost protected against thermal denaturation above 50 °C, where the structural change became irreversible. Beyond 30 °C, the helicity (66%) of the protein sharply decreased with rise of temperature. In response to this, the proportions of β-structure and random coil increased. The helicity and the β-structural proportion were 44% and 13% at 65 °C, respectively. The protective effect was observed upon the coexistence of SDS of extremely low concentrations: the molar ratio of [SDS]/[BSA] of 15 was enough to induce the maximal protective effect on the helical structure of the protein. The maximal protected helicity was 58% at 65 °C, increasing to 64% upon cooling down to 25 °C. This protective effect became greater with an increase of chain length of alkyl sulfate ion. On the other hand, a cationic surfactant did not protect the BSA structure at all against the thermal denaturation. This protective effect was characterized by the specific amphiphilic nature of anionic surfactant. Such an anionic surfactant is considered to protect the protein structure by building bridges between particular nonpolar residues and particular positively charged residues located on different loops of the protein.