Small GTPases are cellular switches that are switched on when bound to GTP and switched off when bound to GDP. Different small GTPase proteins or those with mutations may bind to GTP or GDP with different relative affinities. However, small GTPases generally have very high affinities for guanine nucleotides, rendering it difficult to compare the relative binding affinities for GTP and GDP. Here we developed a method for comparing the relative binding strength of a protein to GTP and GDP using a mant-GDP dissociation assay, whereby the abilities of GTP and GDP to induce the dissociation of

Given the scale of the ongoing COVID-19 pandemic, the need for reliable, scalable testing, and the likelihood of reagent shortages, especially in resource-poor settings, we have developed an RT-qPCR assay that relies on an alternative to conventional viral reverse transcriptases, a thermostable reverse transcriptase/DNA polymerase (RTX) (Ellefson et al., 2016). Here we show that RTX performs comparably to the other assays sanctioned by the CDC and validated in kit format. We demonstrate two modes of RTX use – (i) dye-based RT-qPCR assays that require only RTX polymerase, and (ii) TaqMan