Two-dimensional 1 H and 1 H-detected NMR study of a heterogeneous biocatalyst using fast MAS at high magnetic fields

• Published in: Solid state nuclear magnetic resonance Vol. 92; p. 7
• Main Authors: Varghese, Sabu, Halling, Peter J, Häussinger, Daniel, Wimperis, Stephen
• Format: Journal Article
• Language: English
• Published: Netherlands 01.08.2018
• Subjects: Biocatalysis; Carbonic Anhydrase II - chemistry; Carbonic Anhydrase II - metabolism; Humans; Magnetic Fields; Nuclear Magnetic Resonance, Biomolecular - methods; Time Factors; Solid-state NMR; Biocatalysis; Immobilized enzymes; H MAS NMR; Covalent immobilization; Heterogeneous biocatalysts; hCA II; Epoxy-functionalized silica; Human carbonic anhydrase II
• ISSN: 1527-3326

Nuclear magnetic resonance (NMR) is a powerful tool for investigating atomic-scale structure in heterogeneous or composite materials where long-range order is absent. In this work solid-state H and H-detected NMR experiments were performed with fast magic angle spinning (ν  = 75 kHz) and at high magnetic fields (B  = 20 T) and used to gain structural insight into a heterogeneous biocatalyst consisting of an enzyme, human carbonic anhydrase II (hCA II), covalently immobilized on epoxy-functionalized silica. Two-dimensional H- H NOESY-type correlation experiments were able to provide information on H environments in silica, epoxy-silica and the immobilized enzyme. Two distinct signals originating from water protons were observed: water associated with the surface of the silica and the water associated with the immobilized enzyme. Additional two-dimensional H- H double-single quantum (DQ-SQ) correlation experiments suggested that the immobilized enzyme is not in close contact with the silica surface. Most significantly, comparison of two-dimensional H- N spectra of the immobilized enzyme and the solution-state enzyme confirmed that the structural integrity of the protein is well preserved upon covalent immobilization.