Membraneless compartments, such as complex coacervates, have been hypothesized as plausible prebiotic micro-compartments due to their ability to sequester RNA; however, their compatibility with essential RNA World chemistries is unclear. We show that such compartments can enhance key prebiotically-relevant RNA chemistries. We demonstrate that template-directed RNA polymerization is sensitive to polycation identity, with polydiallyldimethylammonium chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in polycation/RNA coacervates. Differences in RNA diffusion rates between PDAC/RNA and oligoarginine/RNA coacervates imply distinct biophysical environments. Template-directed RNA polymerization is relatively insensitive to Mg2+ concentration when performed in PDAC/RNA coacervates as compared to buffer, even enabling partial rescue of the reaction in the absence of magnesium. Finally, we show enhanced activities of multiple nucleic acid enzymes including two ribozymes and a deoxyribozyme, underscoring the generality of this approach, in which functional nucleic acids like aptamers and ribozymes, and in some cases key cosolutes localize within the coacervate microenvironments.

Widespread testing for the presence of the novel coronavirus SARS-CoV-2 in individuals remains vital for controlling the COVID-19 pandemic prior to the advent of an effective treatment. Challenges in testing can be traced to an initial shortage of supplies, expertise and/or instrumentation necessary to detect the virus by quantitative reverse transcription polymerase chain reaction (RT-qPCR), the most robust, sensitive, and specific assay currently available. Here we show that academic biochemistry and molecular biology laboratories equipped with appropriate expertise and infrastructure can replicate commercially available SARS-CoV-2 RT-qPCR test kits and backfill pipeline shortages. The Georgia Tech COVID-19 Test Kit Support Group, composed of faculty, staff, and trainees across the biotechnology quad at Georgia Institute of Technology, synthesized multiplexed primers and probes and formulated a master mix composed of enzymes and proteins produced in-house. Our in-house kit compares favorably to a commercial product used for diagnostic testing. We also developed an environmental testing protocol to readily monitor surfaces across various campus laboratories for the presence of SARS-CoV-2. Our blueprint should be readily reproducible by research teams at other institutions, and our protocols may be modified and adapted to enable SARS-CoV-2 detection in more resource-limited settings.

Divalent metal cations are essential to the structure and function of the ribosome. Previous characterizations of the ribosome performed under standard laboratory conditions have implicated Mg2+ as a primary mediator of ribosomal structure and function. Possible contributions of Fe2+ as a ribosomal cofactor have been largely overlooked, despite the ribosome's early evolution in a high Fe2+ environment, and the continued use of Fe2+ by obligate anaerobes inhabiting high Fe2+ niches. Here, we show that (i) Fe2+ cleaves RNA by in-line cleavage, a non-oxidative mechanism that has not previously been shown experimentally for this metal, (ii) the first-order in-line rate constant with respect to divalent cations is >200 times greater with Fe2+ than with Mg2+, (iii) functional ribosomes are associated with Fe2+ after purification from cells grown under low O2 and high Fe2+ and (iv) a small fraction of Fe2+ that is associated with the ribosome is not exchangeable with surrounding divalent cations, presumably because those ions are tightly coordinated by rRNA and deeply buried in the ribosome. In total, these results expand the ancient role of iron in biochemistry and highlight a possible new mechanism of iron toxicity.

5Divalent metal cations are essential to the structure and function of the ribosome. Previous 2 6 characterizations of ribosome structure and function performed under standard laboratory 2 7conditions have implicated Mg 2+ as the primary mediator of ribosomal structure and function. 8The contribution of Fe 2+ as a ribosomal cofactor has been largely overlooked, despite the 2 9 ribosome's evolution in a high Fe 2+ environment, and its continued use by obligate anaerobes 3 0 inhabiting high Fe 2+ niches. Here we show that (i) iron readily cleaves RNA by a non-oxidative 3 1 mechanism that has not been detected previously, (ii) functional ribosomes purified from cells 3 2 grown under low O 2 , high Fe 2+ conditions are associated with Fe 2+ , (iii) a small subset of Fe 2+ 3 3that is associated with the ribosome is not exchangeable with surrounding cations, presumably 3 4 because they are highly coordinated by rRNA. In total, these results expand the ancient role of 3 5 iron in biochemistry, suggest a novel method for regulation of translation by iron, and highlight a 3 6 possible new mechanism of iron toxicity. 3 7