Difference between revisions of "Part:BBa M0050"

Latest revision as of 04:14, 3 October 2013

AANDENYALAA. (Very fast) SsrA degradation tag.

This sequence codes for the amino acid sequence AANDENYALAA, which when fused to the C-terminal of proteins, will make the protein susceptible to very fast degradation through SspB-mediated binding to the ClpX protease as well as ClpA protease.

Note that tagged protein degradation rates are dependent on concentration of proteases (ClpX, ClpA) and binding mediators (SspB). Degradation rates are also heavily dependent on protein stability and depend on Km of binding to the protease, which is highly variable with each substrate. Be aware of ClpX, ClpA, and SspB knockouts when using SsrA tags; some expression strains have these mutations.

The following rates of degradation of respective tagged proteins were observed when this tag was linked to the C-terminal of the protein: ~5 Vmax/ [Clpx6] min-1 tagged to Arc from (1), ~0.5%/min on log scale tagged to GFP from (3), ~1 min half life tagged to Arc from (2).

See the following references for further information on degradation rates and mechanisms of this tag: (1)McGinness, Baker, Sauer. 2006. Mol. Cell. 22:701. (2)Flynn et al 2003. Mol. Cell. 11: 671. Flynn et al. 2001. PNAS 98(19): 10584. Anderson et al 1998. App. Env. Microbiol. 64(6):2240.

This is probably the degradation tag used by Elowitz and Leibler in the Repressilator paper. They never explicitly name the tag but reference a paper in which only this version of the tag was effective in designating degradation.
See the improvement of this part at https://parts.igem.org/Part:BBa_K1051206.
Sequence and Features