sb400133g_si_001.pdf (28.98 kB)
Rational Design of Allosteric Regulation of Homoserine Dehydrogenase by a Nonnatural Inhibitor l‑Lysine
journal contribution
posted on 2015-02-20, 00:00 authored by Zhen Chen, Sugima Rappert, An-Ping ZengAllosteric proteins, which can sense
different signals, are interesting
biological parts for synthetic biology. In particular, the design
of an artificial allosteric enzyme to sense an unnatural signal is
both challenging and highly desired, for example, for a precise and
dynamical control of fluxes of growth-essential but byproduct pathways
in metabolic engineering of industrial microorganisms. In this work,
we used homoserine dehydrogenase (HSDH) of Corynebacterium
glutamicum, which is naturally allosterically regulated by
threonine and isoleucine, as an example to demonstrate the feasibility
of reengineering an allosteric enzyme to respond to an unnatural inhibitor l-lysine. For this purpose, the natural threonine binding sites
of HSD were first predicted and verified by mutagenesis experiments.
The threonine binding sites were then engineered to a lysine binding
pocket. The reengineered HSD only responds to lysine inhibition but
not to threonine. This is a significant step toward the construction
of artificial molecular circuits for dynamic control of growth-essential
byproduct formation pathway for lysine biosynthesis.