Ionic strength-dependent denaturation ofThermomyces lanuginosus llipase induced by SDS

TY - JOUR

T1 - Ionic strength-dependent denaturation ofThermomyces lanuginosus llipase induced by SDS

AU - Fanø, Mathias

AU - van de Weert, Marco

AU - Møller, Eva Horn

AU - Kruse, Nanna Aaby

AU - Frøkjær, Sven

PY - 2011/2/1

Y1 - 2011/2/1

N2 - Triglyceride lipase from Thermomyces lanuginosus (TlL) has been reported to be resistant to denaturation by sodium dodecyl sulfate (SDS). We have found that at neutral pH, structural integrity is strongly dependent on ionic strength. In 10 mM phosphate buffer and SDS, the lipase exhibits a far-UV CD spectrum similar to other proteins denatured in this surfactant while the near-UV CD spectrum shows a complete loss of tertiary structure, observations supported by steady state fluorescence spectroscopy. However, when increasing the ionic strength by the addition of NaCl, the lipase was rendered resistant towards SDS denaturation, as observed by all techniques employed. The effect of salt on the critical micelle concentration (CMC) of SDS was observed to correlate with the effect on the degree of SDS-induced denaturation. This finding is compatible with the notion that the concentration of SDS monomers is a crucial factor for SDS-lipase interactions. The presented results are important for the understanding and improvement of protein stability in surfactant systems.

AB - Triglyceride lipase from Thermomyces lanuginosus (TlL) has been reported to be resistant to denaturation by sodium dodecyl sulfate (SDS). We have found that at neutral pH, structural integrity is strongly dependent on ionic strength. In 10 mM phosphate buffer and SDS, the lipase exhibits a far-UV CD spectrum similar to other proteins denatured in this surfactant while the near-UV CD spectrum shows a complete loss of tertiary structure, observations supported by steady state fluorescence spectroscopy. However, when increasing the ionic strength by the addition of NaCl, the lipase was rendered resistant towards SDS denaturation, as observed by all techniques employed. The effect of salt on the critical micelle concentration (CMC) of SDS was observed to correlate with the effect on the degree of SDS-induced denaturation. This finding is compatible with the notion that the concentration of SDS monomers is a crucial factor for SDS-lipase interactions. The presented results are important for the understanding and improvement of protein stability in surfactant systems.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1016/j.abb.2010.11.012

DO - 10.1016/j.abb.2010.11.012

M3 - Journal article

C2 - 21093408

SN - 0003-9861

VL - 506

SP - 92

EP - 98

JO - Archives of Biochemistry and Biophysics

JF - Archives of Biochemistry and Biophysics

IS - 1

ER -