Glycolipid Biosurfactants Activate, Dimerize, and Stabilize Thermomyces lanuginosus Lipase in a pH-Dependent Fashion

TY - JOUR

T1 - Glycolipid Biosurfactants Activate, Dimerize, and Stabilize Thermomyces lanuginosus Lipase in a pH-Dependent Fashion

AU - Madsen, Jens Kvist

AU - Kaspersen, Jørn Døvling

AU - Andersen, Camilla Bertel

AU - Nedergaard Pedersen, Jannik

AU - Andersen, Kell Kleiner

AU - Pedersen, Jan Skov

AU - Otzen, Daniel E

PY - 2017/8/15

Y1 - 2017/8/15

N2 - We present a study of the interactions between the lipase from Thermomyces lanuginosus (TlL) and the two microbially produced biosurfactants (BSs), rhamnolipid (RL) and sophorolipid (SL). Both RL and SL are glycolipids; however, RL is anionic, while SL is a mixture of anionic and non-ionic species. We investigate the interactions of RL and SL with TlL at pH 6 and 8 and observe different effects at the two pH values. At pH 8, neither RL nor SL had any major effect on TlL stability or activity. At pH 6, in contrast, both surfactants increase TlL's thermal stability and fluorescence and activity measurements indicate interfacial activation of TlL, resulting in 3- and 6-fold improved activity in SL and RL, respectively. Nevertheless, isothermal titration calorimetry reveals binding of only a few BS molecules per lipase. Size-exclusion chromatography and small-angle X-ray scattering suggest formation of TlL dimers with binding of small amounts of either RL or SL at the dimeric interface, forming an elongated complex. We conclude that RL and SL are compatible with TlL and constitute promising green alternatives to traditional surfactants.

AB - We present a study of the interactions between the lipase from Thermomyces lanuginosus (TlL) and the two microbially produced biosurfactants (BSs), rhamnolipid (RL) and sophorolipid (SL). Both RL and SL are glycolipids; however, RL is anionic, while SL is a mixture of anionic and non-ionic species. We investigate the interactions of RL and SL with TlL at pH 6 and 8 and observe different effects at the two pH values. At pH 8, neither RL nor SL had any major effect on TlL stability or activity. At pH 6, in contrast, both surfactants increase TlL's thermal stability and fluorescence and activity measurements indicate interfacial activation of TlL, resulting in 3- and 6-fold improved activity in SL and RL, respectively. Nevertheless, isothermal titration calorimetry reveals binding of only a few BS molecules per lipase. Size-exclusion chromatography and small-angle X-ray scattering suggest formation of TlL dimers with binding of small amounts of either RL or SL at the dimeric interface, forming an elongated complex. We conclude that RL and SL are compatible with TlL and constitute promising green alternatives to traditional surfactants.

KW - Ascomycota

KW - Enzyme Stability

KW - Fungal Proteins

KW - Glycolipids

KW - Hot Temperature

KW - Hydrogen-Ion Concentration

KW - Lipase

KW - Surface-Active Agents

KW - X-Ray Diffraction

KW - Journal Article

U2 - 10.1021/acs.biochem.7b00420

DO - 10.1021/acs.biochem.7b00420

M3 - Journal article

C2 - 28726390

SN - 0006-2960

VL - 56

SP - 4256

EP - 4268

JO - Biochemistry

JF - Biochemistry

IS - 32

ER -