Difference between revisions of "Part:BBa K3257069"

Latest revision as of 05:16, 20 October 2019

SsrA(LAA)

This degradation tag has the amino acid sequence of AANDENYALAA. SsrA is a widely-used type of protein degradation tag that commonly consists of 11 amino acid residues and LAA stands for the last 3 amino acid residues of the tag. When fused after a protein, it will cause protein degradation to happen.

SsrA(LAA) is the wild-type SsrA degradation tag and the other 4 degradation tags are mutants of SsrA(LAA) which are expected to have nearly the same or lower degradation rate.

Using EGFP (BBa_E0040 https://parts.igem.org/Part:BBa_E0040) as a reporter protein, we have measured the fluorescent intensity of EGFP attached to different degradation tags at the steady-state (Figure 1), which indicates the degradation rate of each degradation tag when attached after a CDS of a protein.

Figure 1. Degradation tag greatly reduces the protein level at the steady state. WT represents the positive control of EGFP without any tag attachment. The five degradation tags are represented by their last five amino acid sequence. The vertical axis shows the quantitative analysis of EGFP fluorescence (excitation wavelength: 485 nm; detection wavelength: 528 nm), normalized by cell amount (OD600). The fluorescence is quantified by the concentration of green fluorescein, cell number is quantified by the number of silicon beads, both are from the distributed measurement kit. Fluorescence below detection level is eliminated. Error bar stands for the SEM of 3 replicates. t-test is performed between WT and each degradation tag, P<0.0001 (****).

Sequence and Features