23320757, BMC Biotechnol. 2013 Jan 16;13:3. doi: 10.1186/1472-6750-13-3.

Characterization method

enzyme activity assay

Genomic accession number


Nucelotide position range







Halorubrum lacusprofundi/2247

Degradation or Biosynthesis


Cluster number


Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 1167 (+) CDS No
- 2965 - 4137 (+) CDS No
eda 5030 - 5668 (-) CDS No
- 5729 - 6475 (-) TF: DBD-Pfam|HTH_5,DBD-SUPERFAMILY|0040266 No
- 6800 - 8158 (+) TC: gnl|TC-DB|P29822|3.A.1.1.4 Yes
- 8177 - 9247 (+) TC: gnl|TC-DB|P29823|3.A.1.1.4 Yes
- 9247 - 10083 (+) TC: gnl|TC-DB|Q9WYR1|3.A.1.1.39 Yes
- 10086 - 11207 (+) TC: gnl|TC-DB|Q8TZQ3|3.A.1.1.16 Yes
dgoD 11214 - 12362 (+) other Yes
- 12403 - 13257 (+) other Yes
- 13305 - 15407 (-) CAZyme: GH42 Yes
- 15537 - 17576 (+) CAZyme: GH36 Yes
- 17707 - 18663 (+) STP: STP|PfkB No
- 19274 - 19705 (+) CDS No
- 19702 - 20976 (+) CDS No




23320757, BMC Biotechnol. 2013 Jan 16;13:3. doi: 10.1186/1472-6750-13-3.


Cloning, overexpression, purification, and characterization of a polyextremophilic beta-galactosidase from the Antarctic haloarchaeon Halorubrum lacusprofundi.


Karan R, Capes MD, DasSarma P, DasSarma S


BACKGROUND: Halorubrum lacusprofundi is a cold-adapted halophilic archaeon isolated from Deep Lake, a perennially cold and hypersaline lake in Antarctica. Its genome sequencing project was recently completed, providing access to many genes predicted to encode polyextremophilic enzymes active in both extremely high salinity and cold temperatures. RESULTS: Analysis of the genome sequence of H. lacusprofundi showed a gene cluster for carbohydrate utilization containing a glycoside hydrolase family 42 beta-galactosidase gene, named bga. In order to study the biochemical properties of the beta-galactosidase enzyme, the bga gene was PCR amplified, cloned, and expressed in the genetically tractable haloarchaeon Halobacterium sp. NRC-1 under the control of a cold shock protein (cspD2) gene promoter. The recombinant beta-galactosidase protein was produced at 20-fold higher levels compared to H. lacusprofundi, purified using gel filtration and hydrophobic interaction chromatography, and identified by SDS-PAGE, LC-MS/MS, and ONPG hydrolysis activity. The purified enzyme was found to be active over a wide temperature range (-5 to 60 degrees C) with an optimum of 50 degrees C, and 10% of its maximum activity at 4 degrees C. The enzyme also exhibited extremely halophilic character, with maximal activity in either 4 M NaCl or KCl. The polyextremophilic beta-galactosidase was also stable and active in 10-20% alcohol-aqueous solutions, containing methanol, ethanol, n-butanol, or isoamyl alcohol. CONCLUSION: The H. lacusprofundi beta-galactosidase is a polyextremophilic enzyme active in high salt concentrations and low and high temperature. The enzyme is also active in aqueous-organic mixed solvents, with potential applications in synthetic chemistry. H. lacuprofundi proteins represent a significant biotechnology resource and for developing insights into enzyme catalysis under water limiting conditions. This study provides a system for better understanding how H. lacusprofundi is successful in a perennially cold, hypersaline environment, with relevance to astrobiology.