UV-light-driven prebiotic synthesis of iron–sulfur clusters

Abstract

Iron-sulfur clusters are ancient cofactors that play a fundamental role in metabolism and may have impacted the prebiotic chemistry that led to life. However, it is unclear whether iron-sulfur clusters could have been synthesized on prebiotic Earth. Dissolved iron on early Earth was predominantly in the reduced ferrous state, but ferrous ions alone cannot form polynuclear iron-sulfur clusters. Similarly, free sulfide may not have been readily available. Here we show that UV light drives the synthesis of [2Fe-2S] and [4Fe-4S] clusters through the photooxidation of ferrous ions and the photolysis of organic thiols. Iron-sulfur clusters coordinate to and are stabilized by a wide range of cysteine-containing peptides and the assembly of iron-sulfur cluster-peptide complexes can take place within model protocells in a process that parallels extant pathways. Our experiments suggest that iron-sulfur clusters may have formed easily on early Earth, facilitating the emergence of an iron-sulfur-cluster-dependent metabolism.

Protocells realize their potential

“…Increasing the pH would prevent NAD + degradation, but this leads to precipitation of inactive oxo-hydroxo iron complexes. Building on their recent work in which UV-light was shown to promote iron-sulfur cluster formation starting from a range of short cysteine peptide ligands under anoxic conditions, 4 the present study reveals that simple cysteine peptides stabilise and solubilise Fe(III) at higher pH whilst maintaining redox activity.…”

“…However, current methods for (short) prebiotic peptide synthesis remain ineffective for amino acids with functional side chains such as cysteine and serine, and the pronounced nucleophilicity of thiols renders cysteine incompatible with current methods for electrophilic activation of amino acids. Nevertheless, in a broader sense, the work of Bonfio et al 3,4 suggests that the activity of simple iron-sulfur peptides could have helped to couple catabolism with anabolism during early evolution, and exemplifies value accrued by uniting catalysis with compartmentalisation.…”

The miraculous dynamism of the Qur’an: An example of a modern reading reveals a DNA designation

“…In addition, my proposal agrees strongly with experimental results (Rickard 1975;Butler and Rickard 2000) suggesting that in strictly anoxic systems pyrite (FeS 2 , quite present on early Earth) can form very fast by the hydrogen sulfure (H 2 S) oxidation of iron (II) monosulfide (FeS) in aqueous solutions at relatively low temperatures (between 20 and 50°C) very likely similar to those of the beginning of Archean period marked by the emergence of life. Moreover, more recent experimental results show that UV light can drive the synthesis of [2Fe-2S] and [4Fe-4S] clusters and suggest that iron-sulfur clusters may have formed easily on early Earth, facilitating the emergence of an iron-sulfur-cluster-dependent metabolism (Bonfio et al 2017).…”

Effect of UV Radiation on Fluorescent RNA Aptamers’ Functional and Templating Ability

“…In particular, the dual nature of RNA suggests that the complexities of implementing the central dogma of molecular biology could be avoided by using RNA as both genetic carrier and functional molecules, and thus an early RNA World has been proposed as a simpler precursor to more modern cells . Intriguing prebiotic syntheses of ribonucleotides, amino acids, and even iron–sulfur clusters rely on reactions driven by UV radiation. Indeed, UV radiation might have been the largest source of energy available for prebiotic chemistry .…”