Catalysis by Dihydrofolate Reductase from the Psychropiezophile <i>Moritella profunda</i>

Evans, Rhiannon M.; Behiry, Enas M.; Tey, Lai-Hock; Guo, Jiannan; Loveridge, E. Joel; Allemann, Rudolf Konrad

doi:10.1002/cbic.201000341

Cited by 25 publications

(72 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, "Candidatus Scalindua" and other related anammox bacteria were previously found in oil fields with temperatures ranging from 55 to 75°C (73). The psychropiezophile Moritella profunda was found in regions of high pressure and cold temperatures (74), but a recent study demonstrated that the enzyme dihydrofolate reductase in Moritella profunda has subtle structural changes that allow it to remain active under high pressure and temperatures up to 80°C (75).…”

Section: Discussionmentioning

confidence: 99%

Distinctive Microbial Community Structure in Highly Stratified Deep-Sea Brine Water Columns

Bougouffa

Yang

Lee

et al. 2013

Appl Environ Microbiol

View full text Add to dashboard Cite

b Atlantis II and Discovery are two hydrothermal and hypersaline deep-sea pools in the Red Sea rift that are characterized by strong thermohalo-stratification and temperatures steadily peaking near the bottom. We conducted comprehensive vertical profiling of the microbial populations in both pools and highlighted the influential environmental factors. Pyrosequencing of the 16S rRNA genes revealed shifts in community structures vis-à-vis depth. High diversity and low abundance were features of the deepest convective layers despite the low cell density. Surprisingly, the brine interfaces had significantly higher cell counts than the overlying deep-sea water, yet they were lowest in diversity. Vertical stratification of the bacterial populations was apparent as we moved from the Alphaproteobacteria-dominated deep sea to the Planctomycetaceae-or Deferribacteres-dominated interfaces to the Gammaproteobacteria-dominated brine layers. Archaeal marine group I was dominant in the deep-sea water and interfaces, while several euryarchaeotic groups increased in the brine. Across sites, microbial phylotypes and abundances varied substantially in the brine interface of Discovery compared with Atlantis II, despite the near-identical populations in the overlying deep-sea waters. The lowest convective layers harbored interestingly similar microbial communities, even though temperature and heavy metal concentrations were very different. Multivariate analysis indicated that temperature and salinity were the major influences shaping the communities. The harsh conditions and the low-abundance phylotypes could explain the observed correlation in the brine pools. The Red Sea, a part of the Great Rift Valley, was formed when the Arabian plate split from the African plate. Due to the high surface temperature, excess evaporation, and scarcity of rainfall coupled with a lack of a major source of fresh water influx, the Red Sea is one of the hottest and saltiest seawater bodies in the world. Over the past 40 years, oceanographers have discovered 25 brinefilled deeps in the rift valley of the Red Sea (1-6). These deeps are characterized by their anoxic, hypersaline, hyperthermal, and metalliferous conditions at the bottom, representing some of the most unusual and extreme environments on earth (4, 7-9).The deep-sea brine pools Atlantis II and Discovery, which are located in the middle axial rift zone of the Red Sea, represent a rare type of extreme environment with both hypersaline and hydrothermal geochemical characteristics. Since their discovery in 1965, detailed geological and geochemical investigations have been carried out on these two deeps (1). The Atlantis II Deep is a hydrothermally active brine pool with a temperature that has continuously increased from the earliest record of 44.8°C (1, 10) to the current recorded temperature of 68°C. This increase has been attributed to the influx of hot brine supplied by a geyser spring at the bottom of the Atlantis II pool (11), which divides the brine into two stratified anoxic layers with s...

show abstract

Section: Discussionmentioning

confidence: 99%

Distinctive Microbial Community Structure in Highly Stratified Deep-Sea Brine Water Columns

Bougouffa

Yang

Lee

et al. 2013

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Electrospray ionization mass spectrometry was used to determine the degree of isotopic substitution in the heavy enzyme, and structural integrity was confirmed by circular dichroism spectroscopy. Steady-state and stoppedflow kinetic measurements were performed as previously described (38,59). …”

Section: Methodsmentioning

confidence: 99%

Unraveling the role of protein dynamics in dihydrofolate reductase catalysis

Luk

Ruiz‐Pernía

Dawson

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

127

262

View full text Add to dashboard Cite

Protein dynamics have controversially been proposed to be at the heart of enzyme catalysis, but identification and analysis of dynamical effects in enzyme-catalyzed reactions have proved very challenging. Here, we tackle this question by comparing an enzyme with its heavy ( 15 N, 13 C, 2 H substituted) counterpart, providing a subtle probe of dynamics. The crucial hydride transfer step of the reaction (the chemical step) occurs more slowly in the heavy enzyme. A combination of experimental results, quantum mechanics/molecular mechanics simulations, and theoretical analyses identify the origins of the observed differences in reactivity. The generally slightly slower reaction in the heavy enzyme reflects differences in environmental coupling to the hydride transfer step. Importantly, the barrier and contribution of quantum tunneling are not affected, indicating no significant role for "promoting motions" in driving tunneling or modulating the barrier. The chemical step is slower in the heavy enzyme because protein motions coupled to the reaction coordinate are slower. The fact that the heavy enzyme is only slightly less active than its light counterpart shows that protein dynamics have a small, but measurable, effect on the chemical reaction rate.kinetics | computational chemistry | biological chemistry | biophysics | quantum biology

show abstract

“…25 The BsDHFR gene was purchased from Epoch Biolabs. Mutagenic primers for generating BsDHFR-L20M, BsDHFR-A104Q, BsDHFR-P122E, and BsDHFR-P129D were 5′-GTAAGGATAACCGC A TGCCGTGGCACCTGC-3′, 5′-CGCAGAGCTGTTTCGC CA GACCATGCCGATTGTC-3′, 5′-CTAAGATCTTTGCATCTTTC GA AGGGGATACTTTCTATCCAC-3′, and 5′-GGGGATACTTTCTATCCA GA TATTTCTGATGACGAATGG-3′, respectively (changes underlined).…”

Section: Methodsmentioning

confidence: 99%

“…25 Hence, the role of individual amino acids in the thermostability of BsDHFR was investigated here by site-directed mutagenesis by replacing them with the equivalent residues in MpDHFR. While apo-BsDHFR denatures at approximately 67 °C, 21 G. stearothermophilus can thrive at temperatures as high as 75 °C, 26 and additional environmental factors must help maintain the folded structure of BsDHFR in vivo .…”

mentioning

confidence: 99%

Thermal Adaptation of Dihydrofolate Reductase from the Moderate Thermophile Geobacillus stearothermophilus

et al. 2014

Self Cite

View full text Add to dashboard Cite

The thermal melting temperature of dihydrofolate reductase from Geobacillus stearothermophilus (BsDHFR) is ∼30 °C higher than that of its homologue from the psychrophile Moritella profunda. Additional proline residues in the loop regions of BsDHFR have been proposed to enhance the thermostability of BsDHFR, but site-directed mutagenesis studies reveal that these proline residues contribute only minimally. Instead, the high thermal stability of BsDHFR is partly due to removal of water-accessible thermolabile residues such as glutamine and methionine, which are prone to hydrolysis or oxidation at high temperatures. The extra thermostability of BsDHFR can be obtained by ligand binding, or in the presence of salts or cosolvents such as glycerol and sucrose. The sum of all these incremental factors allows BsDHFR to function efficiently in the natural habitat of G. stearothermophilus, which is characterized by temperatures that can reach 75 °C.

show abstract

Catalysis by Dihydrofolate Reductase from the Psychropiezophile Moritella profunda

Cited by 25 publications

References 47 publications

Distinctive Microbial Community Structure in Highly Stratified Deep-Sea Brine Water Columns

Distinctive Microbial Community Structure in Highly Stratified Deep-Sea Brine Water Columns

Unraveling the role of protein dynamics in dihydrofolate reductase catalysis

Thermal Adaptation of Dihydrofolate Reductase from the Moderate Thermophile Geobacillus stearothermophilus

Contact Info

Product

Resources

About