Revision as of 10:42, 30 October 2013

Heavy chain human ferritin

This part is the heavy ferritin subunit from human ferritin, inspired by P02794 [UniParc]. Ferritin is ubiquitous across prokaryotic and eukaryotic systems and is used to buffer intracellular iron. This part, along with the light ferritin subunit, form a 24 multimeric iron sequestering nanoparticle (Chasteen et al., 1991). The difference between light ferritin is that this chain contains a ferroxidase centre. Protein domains which orient toward the core of ferritin molecules cause the oxidation of intracellular iron from Fe^2+ to Fe^3+ to initiate formation of a ferrihydrite core. (Chasteen et al., 1999). These nanoparticles are robust, remain stable at extreme pHs, and withstand temperature variations (Kim et al., 1999).

Ferritin's utility in iGEM

Ferritin as a nanoparticle is interesting for other iGEM teams for two reasons. Firstly, its iron core can be replaced with other compounds to serve different functions. The iGEM Calgary 2013 demonstrated this by chemically modifying recombinant ferritin's iron core into a robust colourmetric reporter. Other intriguing applications include making ferritin’s iron core magnetically active as magnetoferritin (Jordan et al. 2013), using ferritin as a nanocage for other metals, or the incorporation of other reporters such as quantum dots (Naito et al. 2013) (Figure 2).

Secondly, the ferritin nanoparticle is useful for iGEM teams as a self-assembling and spherical protein scaffold. Each of the 24 subunits forming ferritin can be fused to proteins of interest, such that when the nanoparticle assembles, proteins surround the ferritin sphere (Kim et al., 2011). The iGEM Calgary 2013 team demonstrated this by binding DNA sensing proteins, TALEs, as part of their FerriTALE sensor. The Calgary team also constructed ferritin subunits with a coiled-coil linker system so that other teams can scaffold proteins to E-coil ferritin (BBa_K1189018, BBa_K1189019, BBa_K1189020, BBa_K1189037). See Figure 3 for a demonstration of these applications.

References

Sequence and Features