Part:BBa_K844008

Spider Silk 1x Subunit "B" (Balanced tRNA codon optimized) with Met (ATG) added

Spider silk subunit optimized to use a reduced set of tRNA codons (1 to 2 codons per amino acid); contains two elasticity domains and one strength domain, also contains 5’ Met (ATG) codon.

IMPORTANT NOTE: This part uses Assembly Standard #23 (Silver Fusion) scar sites, which the sequence data below and on composite parts using this part will not reflect this scar sequence (it shows Assembly Standard #10 scars).

Usage and Biology

This subunit is based on the 2E subunit from MaSp2 silk gene from Argiope aurantia The DNA sequence was altered from the native sequence so that each of the six amino acids in the silk subunit has either one or two codons representing it (example: all glycines are GGT or GGA in the DNA). See part BBa_K844004 for additional sequence details. This part contains an added Met (ATG) codon at the 5’ end and is designed for use as the first subunit in a longer spider silk construct. This part should be followed by numerous repeats of the BBa_K844004 silk subunit, and the silk coding region should end with a BBa_K844000 part, which contains a 10-Histidine tag and a double stop codon (TAATAA).

The silk subunit contains four main domains: two elasticity domains, a linker domain, and a strength domain. The elasticity domains contains sequences coding for beta-helices and beta-spiral in the protein; these structures increase the elasticity of the spider silk. The linker domain joins the strength and elasticity domains together. The strength domain will form beta-sheets and strengthen the silk fibers by cross-linking silk strands.

Related parts:

BBa_K844002 – the native 2E spider silk subunit with two elasticity domains and one strength domain (no sequence manipulation)

BBa_K844004 – this spider silk subunit without the added Met (ATG) start codon at the 5’ end

BBa_K844016 – this part is an expression unit containing this silk subunit fused to a 10x-His Tag. This protein generator is driven by a lactose/IPTG inducible promoter coupled with a RBS.

References:

Brooks AE, Stricker SM, Joshi SB, Kamerzell TJ, Middaugh CR, and Lewis RV. 2008. Properties of synthetic spider silk fibers based on Argiope aurantia MaSp2. Biomacromolecules 9:1506–10.

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]