Prebiotic protein design supports a halophile origin of foldable proteins

Longo, Liam M.; Blaber, Michael

doi:10.3389/fmicb.2013.00418

Cited by 24 publications

(34 citation statements)

References 18 publications

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“…Notably, the stability data demonstrate that potentially any of the aromatic amino acids (F, Y, or W) substituted into PV2 (involving the mini‐core position) could enable this folding transition, and that the first aromatic amino acid yields the greatest increase in melting temperature. These results are consistent with the observation that aromatic amino acids are significantly more common in the proteomes of mesophiles than in halophiles, perhaps due to the alleviated need for optimized core packing in a halophile context. Therefore, incorporation of aromatic amino acids into early proteins may have facilitated a critical halophile‐to‐mesophile transition.…”

Section: Discussionsupporting

confidence: 90%

“…Thus, without exception, such minimal foldable proteins have depended on critical aromatic amino acids within the core, as well as stabilizing salt bridges (dependent on basic amino acids), to achieve a stable structure. Thus, more work is needed to elucidate the critical question of whether the prebiotic amino acids form a foldable set; however, there is compelling evidence to support the prebiotic foldable set hypothesis, with studies indicating a dependency of such foldability on a halophile environment …”

Section: Discussionmentioning

confidence: 99%

“…Consistent with the proteogenic hypothesis is recent experimental evidence that the prebiotic set of amino acids likely defines a “foldable set” (i.e., is supportive of protein folding) within a halophilic (high salt) environment . The compatibility of prebiotic protein folding and the halophilic environment is due to the unique composition of the prebiotic amino acid alphabet, which is devoid of both basic and aromatic amino acids and is also—a distinctive hallmark of halophile proteomes . High salt serves to stabilize protein structures having reduced hydrophobic packing volume, shields surface acidic charges, and promotes solubility through carboxylate binding of hydrated Na + cations.…”

Section: Introductionmentioning

confidence: 86%

“…The general consensus that aromatic amino acids (both canonical and noncanonical) were essentially absent when life first emerged is supported by several observations. The aromatic amino acids are the largest and most complex of the common α‐amino acids and prebiotic aromatic amino acid synthesis appears highly inefficient (with most abiotic chemical syntheses failing to yield aromatics altogether) . Furthermore, due to an essential lack of ozone in the atmosphere, abiotically generated aromatic compounds (i.e., aromatic amino acids and nucleic acid bases having absorption wavelengths falling within the U.V.…”

Section: Introductionmentioning

confidence: 99%

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A single aromatic core mutation converts a designed “primitive” protein from halophile to mesophile folding

et al. 2014

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Abstract:The halophile environment has a number of compelling aspects with regard to the origin of structured polypeptides (i.e., proteogenesis) and, instead of a curious niche that living systems adapted into, the halophile environment is emerging as a candidate "cradle" for proteogenesis. In this viewpoint, a subsequent halophile-to-mesophile transition was a key step in early evolution. Several lines of evidence indicate that aromatic amino acids were a late addition to the codon table and not part of the original "prebiotic" set comprising the earliest polypeptides. We test the hypothesis that the availability of aromatic amino acids could facilitate a halophile-to-mesophile transition by hydrophobic core-packing enhancement. The effects of aromatic amino acid substitutions were evaluated in the core of a "primitive" designed protein enriched for the 10 prebiotic amino acids (A,D,E,G,I,L,P,S,T,V)-having an exclusively prebiotic core and requiring halophilic conditions for folding. The results indicate that a single aromatic amino acid substitution is capable of eliminating the requirement of halophile conditions for folding of a "primitive" polypeptide. Thus, the availability of aromatic amino acids could have facilitated a critical halophile-tomesophile protein folding adaptation-identifying a selective advantage for the incorporation of aromatic amino acids into the codon table.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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A single aromatic core mutation converts a designed “primitive” protein from halophile to mesophile folding

et al. 2014

Self Cite

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“…However, the high levels of heat flow within the mantle on the early Earth drove a highly active hydrothermal circulatory system that contributed hot, salty (de Ronde et al ., ), silica‐rich fluids to the local environment (Westall, ). It has been proposed that primordial life may have first occurred within hypersaline environments on early Earth (Dundas, ), and recent evidence suggests that the abiotic formation of primitive versions of extant proteins can indeed occur in the presence of NaCl (Longo et al ., ; Longo and Blaber, ). Understanding the way in which water‐condensing chemical reactions could have led to the emergence of key biomolecules (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multiplication of microbes below 0.690 water activity: implications for terrestrial and extraterrestrial life

Stevenson

Burkhardt

Cockell

et al. 2014

Environmental Microbiology

154

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SummarySince a key requirement of known life forms is available water (water activity; a w), recent searches for signatures of past life in terrestrial and extraterrestrial environments have targeted places known to have contained significant quantities of biologically available water. However, early life on Earth inhabited high-salt environments, suggesting an ability to withstand low water-activity. The lower limit of water activity that enables cell division appears to be ∼ 0.605 which, until now, was only known to be exhibited by a single eukaryote, the sugar-tolerant, fungal xerophile Xeromyces bisporus. The first forms of life on Earth were, though, prokaryotic. Recent evidence now indicates that some halophilic Archaea and Bacteria have water-activity limits more or less equal to those of X. bisporus. We discuss water activity in relation to the limits of Earth's present-day biosphere; the possibility of microbial multiplication by utilizing water from thin, aqueous films or non-liquid sources; whether prokaryotes were the first organisms able to multiply close to the 0.605-a w limit; and whether extraterrestrial aqueous milieux of ≥ 0.605 aw can resemble fertile microbial habitats found on Earth.

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The ambivalent role of water at the origins of life

et al. 2020

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Life as we know it would not exist without water. However, water molecules not only serve as a solvent and reactant but can also promote hydrolysis, which counteracts the formation of essential organic molecules. This conundrum constitutes one of the central issues in origin of life. Hydrolysis is an important part of energy metabolism for all living organisms but only because, inside cells, it is a controlled reaction. How could hydrolysis have been regulated under prebiotic settings? Lower water activities possibly provide an answer: geochemical sites with less free and more bound water can supply the necessary conditions for protometabolic reactions. Such conditions occur in serpentinising systems, hydrothermal sites that synthesise hydrogen gas via rock–water interactions. Here, we summarise the parallels between biotic and abiotic means of controlling hydrolysis in order to narrow the gap between biochemical and geochemical reactions and briefly outline how hydrolysis could even have played a constructive role at the origin of molecular self‐organisation.

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Prebiotic protein design supports a halophile origin of foldable proteins

Cited by 24 publications

References 18 publications

A single aromatic core mutation converts a designed “primitive” protein from halophile to mesophile folding

A single aromatic core mutation converts a designed “primitive” protein from halophile to mesophile folding

Multiplication of microbes below 0.690 water activity: implications for terrestrial and extraterrestrial life

The ambivalent role of water at the origins of life

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