SbpA | RFP


Designed by: Timo Wolf   Group: iGEM11_Bielefeld-Germany   (2011-09-10)

Fusion Protein of S-Layer SbpA and mCherry RFP


Fusion Protein of S-Layer sbpA and mCherry RFP

S-layers (crystalline bacterial surface layer) are crystal-like layers consisting of multiple protein monomers and can be found in various (archae-)bacteria. They constitute the outermost part of the cell wall. Especially their ability for self-assembly into distinct geometries is of scientific interest. At phase boundaries, in solutions and on a variety of surfaces they form different lattice structures. The geometry and arrangement is determined by the C-terminal self assembly-domain, which is specific for each S-layer protein. The most common lattice geometries are oblique, square and hexagonal. By modifying the characteristics of the S-layer through combination with functional groups and protein domains as well as their defined position and orientation to eachother (determined by the S-layer geometry) it is possible to realize various practical applications (Sleytr et al., 2007).

Usage and Biology

S-layer proteins can be used as scaffold for nanobiotechnological applications and devices by e.g. fusing the S-layer's self-assembly domain to other functional protein domains. It is possible to coat surfaces and liposomes with S-layers. A big advantage of S-layers: after expressing in E. coli and purification, the nanobiotechnological system is cell-free. This enhances the biological security of a device.

This fluorescent S-layer fusion protein is used to characterize purification methods and the S-layer's ability to self-assemble on surfaces. It is also possible to use the characteristic of mCherry as a pH indicator (Kainz et al., 2010).

Important parameters

Experiment Characteristic Result
Expression (E. coli) Localisation Inclusion body
Compatibility E. coli KRX and BL21(DE3)
Induction of expression expression of T7 polymerase + IPTG or lactose
Purification Molecular weight 136.7 kDa
Theoretical pI 4.92
Excitation / emission 587 / 610 nm
Immobilization behaviour Immobilization time 4 h

Sequence and Features

Assembly Compatibility:
  • 10
  • 12
  • 21
    Illegal BglII site found at 104
    Illegal BglII site found at 221
    Illegal XhoI site found at 1996
  • 23
  • 25
    Illegal NgoMIV site found at 76
    Illegal AgeI site found at 3904
  • 1000
    Illegal BsaI.rc site found at 493
    Illegal BsaI.rc site found at 622

Functional Parameters: Austin_UTexas

BBa_K525404 parameters

Burden Imposed by this Part:

Burden Value: 3.2 ± 5.3%

Burden is the percent reduction in the growth rate of E. coli cells transformed with a plasmid containing this BioBrick (± values are 95% confidence limits). This BioBrick did not exhibit a burden that was significantly greater than zero (i.e., it appears to have little to no impact on growth). Therefore, users can depend on this part to remain stable for many bacterial cell divisions and in large culture volumes. Refer to any one of the BBa_K3174002 - BBa_K3174007 pages for more information on the methods, an explanation of the sources of burden, and other conclusions from a large-scale measurement project conducted by the 2019 Austin_UTexas team.

This functional parameter was added by the 2020 Austin_UTexas team.