Difference between revisions of "Part:BBa K3071006"

Revision as of 07:06, 21 October 2019

Phage shock protein F (PspF)

Descirption

This the protein-encoding gene for the Phage-shock protein pspF, which is originated from escherica coli K12 strain. The SDS-PAGE gel data and western blot data of our composite part (BBa_K3071020) show it could be correctly expressed in escherica coli Bl21(DE3) strain in form of the fusion protein. In our project, the original DNA-binding domain would be replaced by the Clp, leaving the transcription activation domain(TAD) in our biobrick design (BBa_K3071009).

Biology

PspF has a hexameric structure, with α/β and α domains in each monomer (figure 1). It has ATPase activity in E. Coli to promote DNA strand separation, forming the open complex. Loop 1 (L1) and loop 2 (L2) are two loops locate in the α/β domains and α domains respectively. They are responsible for the interaction between PspF and the sigma 54. The 8 to 238 amino acids are the Sigma 54 interactive domain while the DNA strand binding motif is at the amino acid position 302 to 321.

Usage

PspF is a constitutively active enhancer-binding protein for activating the PspA promoter (BBa_K3071013) transcription in vivo. The enhancer is located in -80 to -126 upstream of the pspA transcription start site.

Characterization

The bacteria culture was induced by 1mM IPTG at 32℃ and collected at different time points, which are 12hr, 16hr, 20hr, 24hr, and 28hr. After blotting with corresponding antibodies, pspF-Clp was confirmed with successful expression at all time points. Results of blots probing pspF-Clp showed that clones collected at 12hr contained the highest amount of target proteins and the protein quantity decreased from 16hr to 28hr. This may due to degradation inside the cells.

Sequence and Features