Part:BBa_K4905001

Elastin-Like polypeptide (VPGIG)[60]-(VPGAG)3(VPGGG)2[12]

Information

Elastin-like polypeptides (ELPs) are protein polymers derived from human tropoelastin. One of their key features is that they exhibit a phase separation that is often reversible whereby samples remain soluble below a transition temperature (T_t) but form coacervates above T_t. They have many possible applications in purification, sensing, activation, and nano assembly. Furthermore, they are non-immunogenic, substrates for proteolytic biodegradation, and can be decorated with pharmacologically active peptides, proteins, and small molecules. Recombinant synthesis additionally allows precise control over ELP architecture and molecular weight, resulting in protein polymers with uniform physicochemical properties suited to the design of multifunctional biologics. As such, ELPs have been employed for various uses including as anti-cancer agents, ocular drug delivery vehicles, and protein trafficking modulators^[2].

The general structure of polymeric ELPs is (VPGXG)n, where the monomeric unit is Val-Pro-Gly-X-Gly, and the "X" denotes a variable amino acid that can have consequences on the general properties of the ELP, such as the T_t. Specifically, the hydrophilicity or hydrophobicity and the presence or absence of a charge on the guest residue play a great role in determining the T_t. Also, the solubilization of the guest residue can affect the T_t. The "n" denotes the number of monomeric units that comprise the polymer^[1]. In general, these polymers are linear below the T_t, but aggregate into spherical clumps above the T_t^[3]. The repeating sequence for this specific part is (VPGIG)_[60] and then (VPGAG)₃(VPGGG)_2[12].

The TU-Eindhoven 2023 team used this part in a composite part for the formation of a hydrogel in E. coli. It has been codon optimized for expression in E. coli BL21 cells. The composite part is BBa_K4905006 .

Sequence and Features

the following sequence was used to create this part. It was optimized for E.coli BL21 cells. The sequence was cloned into a pET24a(+) vector, this was multiplied in TOP10 competent cells.

Assembly Compatibility:

• 10
  INCOMPATIBLE WITH RFC[10]

  Illegal EcoRI site found at 1890
  Illegal XbaI site found at 7
  
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal EcoRI site found at 1890
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal EcoRI site found at 1890
  Illegal XhoI site found at 1907
  
• 23
  INCOMPATIBLE WITH RFC[23]

  Illegal EcoRI site found at 1890
  Illegal XbaI site found at 7
  
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal EcoRI site found at 1890
  Illegal XbaI site found at 7
  Illegal NgoMIV site found at 64
  Illegal NgoMIV site found at 244
  Illegal NgoMIV site found at 334
  Illegal NgoMIV site found at 514
  
• 1000
  COMPATIBLE WITH RFC[1000]

Characterization

We ran an electrophoresis gel with the plasmid, digested with enzymes AcuI and BglI. The band of I[60]-A[60] is shown in slot 1. A 60 kb ladder (L) was used. Slot 2 was used for a different part.

1. I[60]-A[60]: AcuI + BglI
2. A[40]-I[60]: BseRI + BglI
3. A[60]-I[60]: BseRI + BglI

Figure 1 | Electrophoresis gel with I[60]-A[60] in slot 1

This digested DNA was used for the development of further composite parts.

References

[1] Christensen, T., Hassouneh, W., Trabbic-Carlson, K., & Chilkoti, A. (2023). Predicting Transition Temperatures of Elastin-Like Polypeptide Fusion Proteins. https://doi.org/10.1021/bm400167h

[2] Despanie, J., Dhandhukia, J. P., Hamm-Alvarez, S. F., & MacKay, J. A. (2016). Elastin-like polypeptides: Therapeutic applications for an emerging class of nanomedicines. Journal of Controlled Release, 240, 93–108. https://doi.org/10.1016/j.jconrel.2015.11.010

[3] Hassouneh, W., Christensen, T., & Chilkoti, A. (2010). Elastin-Like Polypeptides as a Purification Tag for Recombinant Proteins. Current Protocols in Protein Science, 61(1), 6.11.1-6.11.16. https://doi.org/10.1002/0471140864.PS0611S61