Riboswitch is a novel type of posttranscriptional regulatory elements discovered by Breaker et al. in 2002. It can regulate gene expression by binding directly to small metabolites without the aid of protein molecules. Compared to normal protein-mediated regulation, riboswitch responds to metabolites more rapidly and sensitively. Its discovery opens a new world for RNA research. The recent advances in riboswitch researches were summarized, including crystal structure determination, mechanism and dynamics study, biosensor and antibacterial drug design. Topp et al. successfully reprogrammed E. coli to detect, follow, and precisely localize to a completely new chemical signal by using a synthetic riboswitch. This work provided new ideas for synthetic biology and artificial biology network. The advances in riboswitch 3D structure determination, reaction mechanism and dynamics provide useful information for rational drug design towards new generation of riboswitch-targeting antibacterials.

Functional proteins designed de novo have potential application in chemical engineering, agriculture and healthcare. Metal binding sites are commonly used to incorporate functions. Based on a de novo designed protein DS119 with a βαβ structure, we have computationally engineered zinc binding sites into it using a home-made searching program. Seven out of the eight designed sequences tested were shown to bind Zn(2+) with micromolar affinity, and one of them bound Zn(2+) with 1:1 stoichiometry. This is the first time that metalloproteins with an α, β mixed structure have been designed from scratch.
Amino Acid Sequence ; Binding Sites ; Computer Simulation ; Escherichia coli ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Magnetic Resonance Spectroscopy ; Metalloproteins ; chemistry ; genetics ; metabolism ; Models, Molecular ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; Protein Binding ; Protein Engineering ; Protein Structure, Secondary ; Recombinant Proteins ; chemistry ; genetics ; metabolism ; Zinc ; chemistry ; metabolism