2024-03-28T13:13:55Zhttps://riubu.ubu.es/oai/requestoai:riubu.ubu.es:10259/47662023-03-31T12:37:18Zcom_10259_4759com_10259_2604col_10259_4760
Structure and function of Aspergillus niger laccase McoG
Ferraroni, Marta .
Westphal, Adrie H. .
Borsari, Marco .
Tamayo Ramos, Juan Antonio
Briganti, Fabrizio .
Graaff, Leo H. de .
Berkel, Willem J. H. van .
Aspergillus niger
crystal structure
laccase
redox potential
metalloprotein
multicopper oxidase
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.
2018-03-22T08:44:59Z
2018-03-22T08:44:59Z
2018-03-22T08:44:59Z
2017-01
info:eu-repo/semantics/article
2353-1746
http://hdl.handle.net/10259/4766
10.1515/boca-2017-0001
eng
Biocatalysis. 2017, V. 3, n.1, p. 1-16
https://doi.org/10.1515/boca-2017-0001
http://creativecommons.org/licenses/by-nc-nd/3.0
info:eu-repo/semantics/openAccess
Attribution-NonCommercial-NoDerivs 3.0 Unported
De Gruyter