Synthetic biology is a field of science that deals with design of new biomolecular
components, signalling pathways, cascades, and their use to regulate cell function,
reprogramming tissue, and organism organizations. An example of a module is de novo
designed synthetic protein, which forms the motif of a four helical bundle. The module is
represented by four α-helices wrapped together. De novo designed four helical bundles
also have applicative use in mammalian cell lines as dimerization, trimerization or
tetramerization modules. With proper system design, we have shown that it is possible to
regulate the inducible 1: 3 dimerization of α-helices in four helical bundle that can be
regulated via orthogonal viral proteases. The catalytically active protease cleaves the
inserted cleavage site between the dimerization modules of the four helical bundle and
thus induces dimerization. Viral proteases were also used in a cleaved inactive form, the
activity of which is restored with appropriate proximity manipulation. Spatial
approximation was performed via a system of exogenously regulated dimerization of
heterodimerization domains having linker-linked cleaved protease units. With the
addition of an appropriate chemical inducer, the dimerization domains bind. This results
in the spatial approximation of the protease units, and thus the restoration of its catalytic
activity. Time response of the prepared system is faster than the transcriptional regulation.
And it allows a fourfold increase in signal over a time span of 2 h. The inducible
dimerization of the four helical bundle was designed and characterized on the luciferase
reporter system. The luciferase reporter can be replaced with other cellular components
and thus regulate or detect several cellular processes via four helical bundle.
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