Part:BBa_K1442033:Design
C2 3
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25INCOMPATIBLE WITH RFC[25]Illegal NgoMIV site found at 38
Illegal NgoMIV site found at 67 - 1000COMPATIBLE WITH RFC[1000]
Design Notes
Image of sequence generated by using Genious
DNA
5’ GGTTGAACCGTACGCCTTTGTAAATAAACG 3’
RNA and secondary structure
Features
Gel electrophoresis showing replication by HCV RdRP of a number of potential RNA promoters. The bands show the amount of replicated product and its approximate length, and quantify the tendency promoters to produce strands of wrong size. C2 (band 8) shows considerable efficiency in directing replication of the full template, although an amount of incorrect products were also present.
Ribozyme
The use of a ribozyme is necessitated due to the complicated binding process between the RNA template and the RdRP. In order to optimise the process and avoid any risk of unfavourable secondary structures or obstruction by unneeded nucleotides, a self-cleaving ribozyme was put after the RNA promoter. The rationale being that after transctiption (either in vitro for human cell tests or in vivo for e-coli tests), any added bases as a result of the T7 polymerase would be removed from the main template strand.
The chosen ribozyme taken from the Hepatitis Delta virus was investigated at length by the team of J. Doudna and is reported to be the fastest naturally occurring self-cleaving protein. It also functions independently, without the need for adding chemical substances, and is resistant to denaturants. Its close genetic origin to the RdRP also contributes to a better working and more compatible system.
The structure of the molecule and its active site in particular are shown below.
Source
B. Heinz, C. Kao – “Template Requirements for RNA Synthesis by a Recombinant Hepatitis C Virus RNA-Dependent RNA Polymerase” - [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC113194/]
“Crystal structure of a hepatitis delta virus ribozyme”, 1998, Adrian R. Ferré-D'Amaré, Kaihong Zhou and Jennifer A. Doudna