Part:BBa_K4207007

BYDV toehold switch B69

Toehold switch for the detection of BYDV gRNA

Usage and Biology

Toehold switches are engineered riboregulators that control the expression of a downstream protein coding sequence. They can be designed to detect virtually any sequence. Toehold switches are designed in silico so that they fold into a pre-determined secondary structure. This structure contains a stable stem-loop that sequesters the ribosome binding site (RBS) and the start codon, thus preventing translation. After a specific trigger RNA binds to the binding site of the toehold, the lower part of the stem-loop unfolds, revealing the start codon. A weak stem remains, but this structure unfolds upon ribosome binding to the RBS, starting translation (Green et al., 2017). This toehold switch was designed to detect conserved sequences in the X genome. The structural change of the toehold switch is illustrated in Figure 1.

[[[[[Animation]]]]] Figure 1. Toehold switch mechanism. This animation illustrates the operation of the toehold switch. Initially, the structure is in an inactive state and the RBS and the start codon are hidden in the stem-loop. When a specific trigger binds to the binding site, the stem-loop structure opens and the ribosome binding site and start codon are revealed.

To use this toehold switch, it should be assembled in a construct containing a promoter, the toehold switch, and a protein-coding sequence. To prevent frame-shifting, the last nucleotide of this toehold switch is removed from this sequence and it's compatible with iGEM Type IIS assembly.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]