The Resting Oxidized State of Small Laccase Analyzed with Paramagnetic NMR Spectroscopy.
Chemphyschem
; 22(8): 733-740, 2021 04 19.
Article
en En
| MEDLINE
| ID: mdl-33682979
ABSTRACT
The enzyme laccase catalyzes the reduction of dioxygen to water at the trinuclear copper center (TNC). The TNC comprises a type-3 (T3) and a type-2 (T2) copper site. The paramagnetic NMR spectrum of the small laccase from Streptomyces coelicolor (SLAC) without the substrate shows a mixture of two catalytic states, the resting oxidized (RO) state and the native intermediate (NI) state. An analysis of the resonances of the RO state is reported. In this state, hydrogen resonances only of the T3 copper ligands can be found, in the region of 12-22â
ppm. Signals from all six histidine ligands are found and can be attributed to Hδ1, Hß or backbone amide HN nuclei. Two sequence-specific assignments are proposed on the basis of a second-coordination shell variant that also lacks the copper ion at the T1 site, SLAC-T1D/Q291E. This double mutant is found to be exclusively in the RO state, revealing a subtle balance between the RO and the NI states.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Resonancia Magnética Nuclear Biomolecular
/
Lacasa
Idioma:
En
Revista:
Chemphyschem
Asunto de la revista:
BIOFISICA
/
QUIMICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Países Bajos