TY - JOUR

T1 - A solid-state NMR study of the immobilization of alpha-chymotrypsin on mesoporous silica

AU - Faure, Nicole E.

AU - Halling, Peter J.

AU - Wimperis, Stephen

PY - 2014/1/16

Y1 - 2014/1/16

N2 - Solid-state NMR spectroscopy was used to characterize a model biocatalyst system consisting of the enzyme alpha-chymotrypsin covalently immobilized on epoxide-silica ((glycidoxypropyl)trimethoxysilane, GOPS, grafted onto the surface of a silica gel). One- and two-dimensional H-1, C-13, and Si-29 magic angle spinning (MAS) NMR techniques were employed. The support system (epoxide-silica) was characterized first and it was possible to assign silicon and carbon species in both the silica and the GOPS linker. After attachment of the protein, carbonyl carbons (175 ppm) in the immobilized enzyme were visible in C-13 MAS NMR spectra recorded at B-o = 20 T. A number of further changes were observed in the C-13 and Si-29 MAS NMR spectra during the immobilization process, arising from a cross-linking of the surface silica species and an opening of the epoxide functional group by nucleophilic attack. This study shows the potential of multinuclear solid-state NMR for obtaining a better understanding of solid biocatalyst systems at the molecular level.

AB - Solid-state NMR spectroscopy was used to characterize a model biocatalyst system consisting of the enzyme alpha-chymotrypsin covalently immobilized on epoxide-silica ((glycidoxypropyl)trimethoxysilane, GOPS, grafted onto the surface of a silica gel). One- and two-dimensional H-1, C-13, and Si-29 magic angle spinning (MAS) NMR techniques were employed. The support system (epoxide-silica) was characterized first and it was possible to assign silicon and carbon species in both the silica and the GOPS linker. After attachment of the protein, carbonyl carbons (175 ppm) in the immobilized enzyme were visible in C-13 MAS NMR spectra recorded at B-o = 20 T. A number of further changes were observed in the C-13 and Si-29 MAS NMR spectra during the immobilization process, arising from a cross-linking of the surface silica species and an opening of the epoxide functional group by nucleophilic attack. This study shows the potential of multinuclear solid-state NMR for obtaining a better understanding of solid biocatalyst systems at the molecular level.

KW - NUCLEAR MAGNETIC-RESONANCE

KW - CROSS-POLARIZATION

KW - SUPPORT

KW - ENZYMES

KW - LIPASE

KW - HYDROLYSIS

KW - TITRATION

KW - PROTEINS

KW - FOAMS

KW - SI-29

U2 - 10.1021/jp4098414

DO - 10.1021/jp4098414

M3 - Journal article

VL - 118

SP - 1042

EP - 1048

JO - The Journal of Physical Chemistry C

JF - The Journal of Physical Chemistry C

SN - 1932-7447

IS - 2

ER -