An Antarctic Extreme Halophile and Its Polyextremophilic Enzyme: Effects of Perchlorate Salts
PublisherMary Ann Liebert Inc.
MetadataShow full item record
AbstractEffects of perchlorate salts prevalent on the surface of Mars are of significant interest to astrobiology from the perspective of potential life on the Red Planet. Halorubrum lacusprofundi, a cold-adapted halophilic Antarctic archaeon, was able to grow anaerobically on 0.04 M concentration of perchlorate. With increasing concentrations of perchlorate, growth was inhibited, with half-maximal growth rate in ca. 0.3 M NaClO4 and 0.1 M Mg(ClO4)2 under aerobic conditions. Magnesium ions were also inhibitory for growth, but at considerably higher concentrations, with half-maximal growth rate above 1 M. For a purified halophilic ?-galactosidase enzyme of H. lacusprofundi expressed in Halobacterium sp. NRC-1, 50% inhibition of catalytic activity was observed at 0.88 M NaClO4 and 0.13 M Mg(ClO4)2. Magnesium ions were a more potent inhibitor of the enzyme than of cell growth. Steady-state kinetic analysis showed that Mg(ClO4)2 acts as a mixed inhibitor (KI = 0.04 M), with magnesium alone being a competitive inhibitor (KI = 0.3 M) and perchlorate alone acting as a very weak noncompetitive inhibitor (KI = 2 M). Based on the estimated concentrations of perchlorate salts on the surface of Mars, our results show that neither sodium nor magnesium perchlorates would significantly inhibit growth and enzyme activity of halophiles. This is the first study of perchlorate effects on a purified enzyme. � Victoria J. Laye and Shiladitya DasSarma. 2018.
SponsorsWe thank Priya DasSarma for assistance with culturing of halophiles. This work was supported by National Aeronautics and Space Administration grant NNX15AM07G.
Identifier to cite or link to this itemhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85045838301&doi=10.1089%2fast.2017.1766&partnerID=40&md5=8445a0e559c9f9e69b3c4552c4206696; http://hdl.handle.net/10713/8800
- Cloning, overexpression, purification, and characterization of a polyextremophilic β-galactosidase from the Antarctic haloarchaeon Halorubrum lacusprofundi.
- Authors: Karan R, Capes MD, DasSarma P, DasSarma S
- Issue date: 2013 Jan 16
- Perchlorate Salts Exert a Dominant, Deleterious Effect on the Structure, Stability, and Activity of α-Chymotrypsin.
- Authors: Gault S, Cockell CS
- Issue date: 2021 Apr
- Perchlorate and halophilic prokaryotes: implications for possible halophilic life on Mars.
- Authors: Oren A, Elevi Bardavid R, Mana L
- Issue date: 2014 Jan
- Key amino acid residues conferring enhanced enzyme activity at cold temperatures in an Antarctic polyextremophilic β-galactosidase.
- Authors: Laye VJ, Karan R, Kim JM, Pecher WT, DasSarma P, DasSarma S
- Issue date: 2017 Nov 21
- Can Halophilic and Psychrophilic Microorganisms Modify the Freezing/Melting Curve of Cold Salty Solutions? Implications for Mars Habitability.
- Authors: Garcia-Descalzo L, Gil-Lozano C, Muñoz-Iglesias V, Prieto-Ballesteros O, Azua-Bustos A, Fairén AG
- Issue date: 2020 Sep