Hyper‐thermostability of CutA1 protein, with a denaturation temperature of nearly 150 °C

Tanaka, Tomoyuki; Sawano, Masahide; Ogasahara, Kyoko; Sakaguchi, Yasushi; Bagautdinov, B.; Katoh, Etsuko; Kuroishi, Chizu; Shinkai, Akeo; Yokoyama, Shigeyuki; Yutani, Katsuhide

doi:10.1016/j.febslet.2006.06.084

Cited by 59 publications

(87 citation statements)

References 34 publications

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“…Obviously, the proteins constituting thermo-and hyperthermophiles organisms must maintain their native structure at temperatures at which their homologues in mesophilic organisms are unfolded. Indeed, some proteins have denaturation temperature of about 150 ºC (88). Comparisons of X-ray structures of functionally homologous proteins from thermo-/hyperthermophilic organisms and from mesophilic organisms revealed the striking fact that they do not differ in fold, and generally speaking, exhibit only minor structural variation.…”

Section: Electrostatic Contribution To Protein Thermal Stabilitymentioning

confidence: 99%

Defining the Role of Salt Bridges in Protein Stability

Jelesarov

Karshikoff

2008

Methods in Molecular Biology

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Running head: Salt bridges and protein stability 2 (i) SummaryAlthough the energetic balance of forces stabilizing proteins has been established qualitatively over the last decades, quantification of the energetic contribution of particular interactions still poses serious problems. The reasons are the strong cooperativity and the interdependence of noncovalent interactions. Salt bridges are a typical example. One expects that ionizable side chains frequently form ion pairs in innumerable crystal structures. Since electrostatic attraction between opposite charges is strong per se, salt bridges can intuitively be regarded as an important factor stabilizing the native structure. Is that really so? In this chapter we critically reassess the available methods to delineate the role of electrostatic interactions and salt bridges to protein stability, and discuss the progress and the obstacles in this endeavor. The basic problem is that formation of salt bridges depends on the ionization properties of the participating groups, which is significantly influenced by the protein environment. Furthermore, salt bridges experience thermal fluctuations, continuously break and re-form, and their lifespan in solution is governed by the flexibility of the protein. Finally, electrostatic interactions are long-range and might be significant in the unfolded state, thus seriously influencing the energetic profile. Elimination of salt bridges by protonation/deprotonation at extreme pH or by mutation provides only rough energetic estimates, since there is no way to account for the non-additive response of the protein moiety. From what we know so far, the strength of electrostatic interactions is strongly contextdependent, yet it is unlikely that salt bridges are dominant factors governing protein stability.Nevertheless, proteins from thermophiles and hyperthermophiles exhibit more, and frequently networked, salt bridges than proteins from the mesophilic counterparts. Increasing the thermal (not the thermodynamic) stability of proteins by optimization of charge-charge interactions is a good example for an evolutionary solution utilizing physical factors.(ii) Keywords: electrostatic interactions, salt bridge, protein stability, thermal stability, denatured state, pK, protein unfolding 3

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Section: Electrostatic Contribution To Protein Thermal Stabilitymentioning

confidence: 99%

Defining the Role of Salt Bridges in Protein Stability

Jelesarov

Karshikoff

2008

Methods in Molecular Biology

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“…On Earth, organisms that grow at 395 K are known (Lovley & Kashefi 2003;Takai et al 2008) and have been cultured in the lab at elevated pressures equal to in situ pressures. Furthermore, proteins can function at 410-420 K (Tanaka et al 2006;Sawano et al 2007;Unsworth et al 2007), motivating a consensus that life at 420 K is plausible (Deming & Baross 1993;Cowan 2004).…”

Section: Upper Temperatures For Lifementioning

confidence: 99%

BIOSIGNATURE GASES IN H₂-DOMINATED ATMOSPHERES ON ROCKY EXOPLANETS

Seager

Bains

2013

ApJ

160

201

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Super-Earth exoplanets are being discovered with increasing frequency and some will be able to retain stable H 2 -dominated atmospheres. We study biosignature gases on exoplanets with thin H 2 atmospheres and habitable surface temperatures, using a model atmosphere with photochemistry and a biomass estimate framework for evaluating the plausibility of a range of biosignature gas candidates. We find that photochemically produced H atoms are the most abundant reactive species in H 2 atmospheres. In atmospheres with high CO 2 levels, atomic O is the major destructive species for some molecules. In Sun-Earth-like UV radiation environments, H (and in some cases O) will rapidly destroy nearly all biosignature gases of interest. The lower UV fluxes from UV-quiet M stars would produce a lower concentration of H (or O) for the same scenario, enabling some biosignature gases to accumulate. The favorability of low-UV radiation environments to accumulate detectable biosignature gases in an H 2 atmosphere is closely analogous to the case of oxidized atmospheres, where photochemically produced OH is the major destructive species. Most potential biosignature gases, such as dimethylsulfide and CH 3 Cl, are therefore more favorable in low-UV, as compared with solar-like UV, environments. A few promising biosignature gas candidates, including NH 3 and N 2 O, are favorable even in solar-like UV environments, as these gases are destroyed directly by photolysis and not by H (or O). A more subtle finding is that most gases produced by life that are fully hydrogenated forms of an element, such as CH 4 and H 2 S, are not effective signs of life in an H 2 -rich atmosphere because the dominant atmospheric chemistry will generate such gases abiologically, through photochemistry or geochemistry. Suitable biosignature gases in H 2 -rich atmospheres for super-Earth exoplanets transiting M stars could potentially be detected in transmission spectra with the James Webb Space Telescope.

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“…Several rational design approaches have been proposed to improve the thermal stability of a protein. Those methods include improving hydrophobic interactions and interior core packing (Clark et al 2004 ;Dong et al 2008 ), increasing the number of ion-pairs and ion-pair networks on the protein surface (Christodoulou et al 2003 ;Tanaka et al 2006 ), introducing a disulfi de bond (Ivens et al 2002 ), and increasing the number of ion-pairs or improving hydrophobic interactions between subunits (Kirino et al 1994 ;Cheung et al 2005 ). However, the effect of each modifi cation is usually small and often strongly depends on its structural context.…”

Section: Ancestral Sequence Reconstruction For Designing Thermally Stmentioning

confidence: 98%

A Strategy for Designing Thermostable Enzymes by Reconstructing Ancestral Sequences Possessed by Ancient Life

Akanuma

Yamagishi

2016

Biotechnology of Extremophiles:

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Hyper‐thermostability of CutA1 protein, with a denaturation temperature of nearly 150 °C

Cited by 59 publications

References 34 publications

Defining the Role of Salt Bridges in Protein Stability

Defining the Role of Salt Bridges in Protein Stability

BIOSIGNATURE GASES IN H₂-DOMINATED ATMOSPHERES ON ROCKY EXOPLANETS

A Strategy for Designing Thermostable Enzymes by Reconstructing Ancestral Sequences Possessed by Ancient Life

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Hyper‐thermostability of CutA1 protein, with a denaturation temperature of nearly 150 °C

Cited by 59 publications

References 34 publications

Defining the Role of Salt Bridges in Protein Stability

Defining the Role of Salt Bridges in Protein Stability

BIOSIGNATURE GASES IN H2-DOMINATED ATMOSPHERES ON ROCKY EXOPLANETS

A Strategy for Designing Thermostable Enzymes by Reconstructing Ancestral Sequences Possessed by Ancient Life

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BIOSIGNATURE GASES IN H₂-DOMINATED ATMOSPHERES ON ROCKY EXOPLANETS