RT info:eu-repo/semantics/article
T1 Structure and function of Aspergillus niger laccase McoG
A1 Ferraroni, Marta .
A1 Westphal, Adrie H. .
A1 Borsari, Marco .
A1 Tamayo Ramos, Juan Antonio
A1 Briganti, Fabrizio .
A1 Graaff, Leo H. de .
A1 Berkel, Willem J. H. van .
K1 Aspergillus niger
K1 crystal structure
K1 laccase
K1 redox potential
K1 metalloprotein
K1 multicopper oxidase
K1 Química física
K1 Chemistry, Physical and theoretical
AB The ascomycete Aspergillus niger produces several multicopper oxidases, but their biocatalytic properties remain largely unknown. Elucidation of the crystal structure of A. niger laccase McoG at 1.7 Å resolution revealed that the C-terminal tail of this glycoprotein blocks the T3 solvent channel and that a peroxide ion bridges the two T3 copper atoms. Remarkably, McoG contains a histidine (His253) instead of the common aspartate or glutamate expected to be involved in catalytic proton transfer with phenolic compounds. The crystal structure of H253D at 1.5 Å resolution resembles the wild type structure. McoG and the H253D, H253A and H253N variants have similar activities with 2,2’-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid or N,N-dimethyl-p-phenylenediamine sulphate. However, the activities of H253A and H253N with 2-amino-4-methylphenol and 2-amino-4-methoxyphenol are strongly reduced compared to that of wild type. The redox potentials and electron transfer rates (ks) of wild type and variants were determined (McoG wt E°’ is +453 mV), and especially the reduced ks values of H253A and H253N show strong correlation with their low activity on phenolic compounds. In summary, our results suggest that the His253 adaptation of McoG can be beneficial for the conversion of phenolic compounds.
PB De Gruyter
SN 2353-1746
YR 2017
FD 2017-01
LK http://hdl.handle.net/10259/4766
UL http://hdl.handle.net/10259/4766
LA eng
DS Repositorio Institucional de la Universidad de Burgos
RD 26-abr-2024