salt and some cations (all at physiological temperature, 37 °C, and pH 7.3–7.4). Z-DNA can form a junction with B-DNA (called a "B-to-Z junction box") in a structure which involves the extrusion of a base pair. The Z-DNA conformation has been difficult to study because it does not exist as a stable feature of the double helix. Instead, it is a transient structure that is occasionally induced by biological activity and then quickly disappears. Predicting Z-DNA structure It is possible to predict the likelihood of a DNA sequence forming a Z-DNA structure. An algorithm for predicting the propensity of DNA to flip from the B-form to the Z-form, ZHunt, was written by P. Shing Ho in 1984 at MIT. This algorithm was later developed by Tracy Camp, P. Christoph Champ, Sandor Maurice, and Jeffrey M. Vargason for genome-wide mapping of Z-DNA (with Ho as the principal investigator). Pathway of formation of Z-DNA from B-DNA Since the discovery and crystallization of Z-DNA in 1979, the configuration has left scientists puzzled about the pathway and mechanism from the B-DNA configuration to the Z-DNA configuration. The conformational change from B-DNA to the Z-DNA structure was unknown at the atomic level, but in 2010, computer simulations conducted by Lee et al. were able to computationally determine that the step-wise propagation of a B-to-Z transition would provide a lower energy barrier than the previously hypothesized concerted mechanism. Since this was computationally proven, the pathway would still need to be tested experimentally in the lab for further confirmation and validity, in which Lee et al. specifically states in their journal article, "The current [computational] result could be tested by Single-molecule FRET (smFRET) experiments in the future." In 2018, the pathway from B-DNA to Z-DNA was experimentally proven using smFRET assays. This was performed by measuring the intensity values between the donor and acceptor fluorescent dyes, also known as Fluorophores, in relation to each other as they exchange electrons, while tagged onto a DNA molecule. The distances between the fluorophores could be used to quantitatively calculate the changes in proximity of the dyes and conformational changes in the DNA. A Z-DNA high affinity binding protein, hZαADAR1, was used at varying concentrations to induce the transformation from B-DNA to Z-DNA. The smFRET assays revealed a B* transition state, which formed as the binding of hZαADAR1 accumulated on the B-DNA structure and stabilized it. This step occurs to avoid