Part:BBa_K5396002

Nt2RepCt-SpyTag

This Nt2RepCt protein has a SpyTag, a 13-amino-acid peptide that is part of the SpyCatcher-SpyTag system, which can enable irreversible protein conjugation.

This part was used as template to construct:

• BBa_K5396005
• BBa_K5396006
• BBa_K5396009
• BBa_K5396010
• and BBa_K5396011

Usage and Biology

Nt2RepCt

Spidroins are the primary proteins that compose spider silk, renowned for their exceptional mechanical properties, including strength, elasticity, and biodegradability. These proteins are produced in specialized glands of spiders and it can have various functions, such as web construction, prey capture, and mobility.

Spidroins are characterized by repetitive amino acid sequences that contribute to their unique structural properties[1]. They typically consist of two main domains:

• N-terminal domain (Nt): This region is involved in the initial formation of silk fibers and is crucial for the protein's solubility and stability.
• C-terminal domain (Ct):This domain plays a significant role in the dimerization of spidroins and helps prevent aggregation during storage. The Ct has been shown to adopt a dimeric folding structure that is conserved across different types of spidroins, indicating a common functional role in silk formation

The repetitive sequences within spidroins often contain motifs rich in glycine and alanine, which facilitate the formation of β-sheet structures that enhance the mechanical properties of the silk fibers.

[2] NT2RepCT features a complex structure that includes both repetitive elements and unique sequences that distinguish it from other spidroins. The N-terminal domain forms amyloid-like fibrils capable of creating hydrogels, which can serve as a platform for protein immobilization.

Figure 1. 3D simulation of Nt2RepCt.

SpyTag

The SpyTag is a 13-amino-acid peptide that plays a crucial role in the SpyCatcher-SpyTag system, a powerful tool for protein engineering and conjugation. This system was developed from a modified domain of the surface protein CnaB2 from Streptococcus pyogenes, which naturally forms isopeptide bonds to aid in bacterial adhesion to host cells. The SpyTag peptide specifically reacts with the protein SpyCatcher, resulting in an irreversible covalent bond that facilitates various biotechnological applications.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

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• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]