Part:BBa_K4322006

CsgA-γ (CsgA-Fibrin Hole Domain Fusion Protein)

CsgA is the polymer forming unit of the curli biogenesis pathway which leads to biofilm formation in Escherichia coli. The wild-type csgA monomer can already self-assemble to form homopolymers outside of the cell. However, for other purposes such as creating a hydrogel, the interaction between wild type csgA monomers lacks sufficient stability[2].

The mammalian protein fibrin arranges into fibrous chains to produce clots that hinder further blood loss. The polymerization of these chains relies on the interaction between N-terminal A- and B-knobs (alpha) and corresponding a- and b-holes (gamma) in the γ- and β-modules of fibrin[1].

When fused with protein csgA of the curli operon and chromoproteins, the fibrin knob domain (alpha)BBa K4322001 and the fibrin hole domain (gamma) BBa K4322002 will interact (as they do in fibrin) to form long polymers that are covalently linked to chromoproteins.

References:

[1]R. I. Litvinov et al., “Polymerization of fibrin: direct observation and quantification of individual B:b knob-hole interactions,” Blood, vol. 109, no. 1, pp. 130–138, Jan. 2007, doi: 10.1182/blood-2006-07-033910.

[2]A. M. Duraj-Thatte et al., “Programmable microbial ink for 3D printing of living materials produced from genetically engineered protein nanofibers,” Nat Commun, vol. 12, no. 1, p. 6600, Dec. 2021, doi: 10.1038/s41467-021-26791-x.