Characterization of a novel high-pH-tolerant laccase-like multicopper oxidase and its sequence diversity in Thioalkalivibrio sp.
Appl Microbiol Biotechnol
; 99(23): 9987-99, 2015 Dec.
Article
en En
| MEDLINE
| ID: mdl-26227413
ABSTRACT
Laccases are oxidoreductases mostly studied in fungi, while bacterial laccases remain poorly studied despite their high genetic diversity and potential for biotechnological application. Our previous bioinformatic analysis identified alkaliphilic bacterial strains Thioalkalivibrio sp. as potential sources of robust bacterial laccases that would be stable at high pH. In the present work, a gene for a laccase-like enzyme from Thioalkalivibrio sp. ALRh was cloned and expressed as a 6× His-tagged protein in Escherichia coli. The purified enzyme was a pH-tolerant laccase stable in the pH range between 2.1 and 9.9 at 20 °C as shown by intrinsic fluorescence emission spectrometry. It had optimal activities at pH 5.0 and pH 9.5 with the laccase substrates 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,6-dimethoxyphenol, respectively. In addition, it could oxidize several other monophenolic compounds and potassium hexacyanoferrate(II) but not tyrosine. It showed highest activity at 50 °C, making it suitable for prolonged incubations at this temperature. The present study shows that Thioalkalivibrio sp. encodes an active, alkaliphilic, and thermo-tolerant laccase and contributes to our understanding of the versatility of bacterial laccase-like multicopper oxidases in general.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Variación Genética
/
Proteínas Recombinantes de Fusión
/
Ectothiorhodospiraceae
/
Lacasa
Idioma:
En
Revista:
Appl Microbiol Biotechnol
Año:
2015
Tipo del documento:
Article
País de afiliación:
Eslovenia