Team:Heidelberg/Toolbox/Oligomerization

Split inteins constitute a useful tool to produce huge polymers in vivo: Hauptmann et al. managed to fabricate synthetic spider silk with microfiber structure. The results using an easy-to-handle split intein system were stunning: The polymers had a molecular weight of 250 kDa and more.[1]

Standardization of a unique tool

The valuable properties of spider silk, for example its exceptional strength and elasticity, result from numerous repeats of certain protein motifs. Convenitonal methods to multimerize these motifs bear a lot of difficulties: Often genetic and mRNA instability constitute a barrier for the production of multimers as fusion proteins.[1] Posttranslational assembly through split inteins is therefore the solution to overcome these problems. The successfull polimerization of spider silk potein motifs demonstrates the potential of split inteins to be a useful tool for the production of new biomaterials by performing oligomerization reactions with split inteins. The iGEM team Heidelberg standardized (lik to toolbox guide) the oligomerization procedure with split inteins to allow easy handling with different proteins.

The mechanism

Oligomerization reactions require the same constructs as the ones used for protein circularization.

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Circularization is achieved by bringing the N and C terminus of a protein very close together, so both intein parts can asseble, cut out off the protein and thereby circularize it. In contrast, oligomerization occurs when the both termini of a protein cannot reach each other and the intein parts of two neighbouring proteins assemble, at the same assembling the protein parts.

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References

[1] Hauptmann, V. et al.: Native-sized spider silk proteins synthesized in planta via intein-based multimerization. Transgenic Res (2013) 22:369–377. DOI 10.1007/s11248-012-9655-6.