Identification of a novel copper-activated and halide-tolerant laccase in Geobacillus thermopakistaniensis.
Genome search of Geobacillus thermopakistaniensis, formerly Geobacillus sp. SBS-4S, revealed the presence of an open reading frame (ESU71923) annotated as laccase. However, the gene product did not display any laccase-like activity against the substrates examined. The laccase activity was, therefore, purified from G. thermopakistaniensis cells and N-terminal amino acid residues of the enzyme were determined. These residues matched the N-terminal sequence of an open reading frame annotated as a copper oxidase (ESU72270). In order to characterize the enzyme, recombinant ESU72270 was prepared in Escherichia coli. The recombinant protein was found to exhibit a negligible amount of laccase activity when produced in the absence of copper in the growth medium. However, the recombinant protein exhibited significantly high laccase activity when produced in the presence of copper. The recombinant enzyme showed highest activity at 60 °C and a pH of 7-7.5. The purified enzyme was highly tolerant to various halides and organic solvents, thus having a potential for various industrial applications. To the best of our knowledge, this is the first characterization of a laccase from genus Geobacillus which identifies a gene responsible for functional laccase in this genus.
School of Biological Sciences, University of the Punjab, Lahore, 54590, Pakistan.
Saadia
S
Basheer
School of Biological Sciences, University of the Punjab, Lahore, 54590, Pakistan. naeem.ff.sbs@pu.edu.pk.
Naeem
N
Rashid
School of Biological Sciences, University of the Punjab, Lahore, 54590, Pakistan.
Raza
R
Ashraf
Department of Botany, GC University, Faisalabad, 38000, Pakistan.
Muhammad Sohail
MS
Akram
Department of Chemistry, Biotechnology Research Laboratory, University of Balochistan, Quetta, Pakistan.
Masood Ahmed
MA
Siddiqui
The Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Tadayuki
T
Imanaka
School of Biological Sciences, University of the Punjab, Lahore, 54590, Pakistan.|School of Biological Sciences, University of Southampton, Southampton, SO16 7PX, UK.
Muhammad
M
Akhtar
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001965:Bromides / Q000737:chemistry; D002712:Chlorides / Q000378:metabolism; D003300:Copper / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D056506:Geobacillus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D042845:Laccase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames; D013379:Substrate Specificity
D001426:Bacterial Proteins; D001965:Bromides; D002712:Chlorides; D003300:Copper; D042845:Laccase
Copper oxidase; Geobacillus thermopakistaniensis; Halide-tolerant; Laccase; Thermostable