TY - JOUR
T1 - Conformational changes and orientation of Humicola lanuginosa lipase on a solid hydrophobic surface
T2 - An in situ interface Fourier transform infrared-attenuated total reflection study
AU - Noinville, Sylvie
AU - Revault, Madeleine
AU - Baron, Marie Hélène
AU - Tiss, Ali
AU - Yapoudjian, Stéphane
AU - Ivanova, Margarita
AU - Verger, Robert
PY - 2002/1/1
Y1 - 2002/1/1
N2 - This study was done to better understand how lipases are activated at an interface. We investigated the conformational and solvation changes occurring during the adsorption of Humicola lanuginosa lipase (HLL) onto a hydrophobic surface using Fourier transform infrared-attenuated total reflection spectroscopy. The hydrophobic surfaces were obtained by coating silicon attenuated total reflection crystal with octadecyltrichlorosilane. Analysis of vibrational spectra was used to compare the conformation of HLL adsorbed at the aqueous-solid interface with its conformation in solution. X-ray crystallography has shown that HLL exists in two conformations, the closed and open forms. The conformational changes in HLL caused by adsorption onto the surface were compared with those occurring in three reference proteins, bovine serum albumin, lysozyme, and α-chymotrypsin. Adsorbed protein layers were prepared using proteins solutions of 0.005 to 0.5 mg/mL. The adsorptions of bovine serum albumin, lysozyme, and α-chymotrypsin to the hydrophobic support were accompanied by large unfoldings of ordered structures. In contrast, HLL underwent no secondary structure changes at first stage of adsorption, but there was a slight folding of β-structures as the lipase monolayer became complete. Solvation studies using deuterated buffer showed an unusual hydrogen/deuterium exchange of the peptide. CONH groups of the adsorbed HLL molecules. This exchange is consistent with the lipase being in the native open conformation at the water/hydrophobic interface.
AB - This study was done to better understand how lipases are activated at an interface. We investigated the conformational and solvation changes occurring during the adsorption of Humicola lanuginosa lipase (HLL) onto a hydrophobic surface using Fourier transform infrared-attenuated total reflection spectroscopy. The hydrophobic surfaces were obtained by coating silicon attenuated total reflection crystal with octadecyltrichlorosilane. Analysis of vibrational spectra was used to compare the conformation of HLL adsorbed at the aqueous-solid interface with its conformation in solution. X-ray crystallography has shown that HLL exists in two conformations, the closed and open forms. The conformational changes in HLL caused by adsorption onto the surface were compared with those occurring in three reference proteins, bovine serum albumin, lysozyme, and α-chymotrypsin. Adsorbed protein layers were prepared using proteins solutions of 0.005 to 0.5 mg/mL. The adsorptions of bovine serum albumin, lysozyme, and α-chymotrypsin to the hydrophobic support were accompanied by large unfoldings of ordered structures. In contrast, HLL underwent no secondary structure changes at first stage of adsorption, but there was a slight folding of β-structures as the lipase monolayer became complete. Solvation studies using deuterated buffer showed an unusual hydrogen/deuterium exchange of the peptide. CONH groups of the adsorbed HLL molecules. This exchange is consistent with the lipase being in the native open conformation at the water/hydrophobic interface.
UR - http://www.scopus.com/inward/record.url?scp=0036228355&partnerID=8YFLogxK
U2 - 10.1016/S0006-3495(02)75612-9
DO - 10.1016/S0006-3495(02)75612-9
M3 - Article
C2 - 11964257
AN - SCOPUS:0036228355
VL - 82
SP - 2709
EP - 2719
JO - Biophysical Journal
JF - Biophysical Journal
SN - 0006-3495
IS - 5
ER -