Part:BBa_K4628003

Enhancer

A nanoantibody derived from alpaca that specifically recognizes GFP, making its fluorescence intensity increase after binding.

Introduction to Nanoantibodies

Nanoantibody is a naturally absent light chain antibody present in the peripheral blood of alpacas, which only contains one heavy chain variable region (VHH) and two conventional CH2 and CH3 regions. Unlike artificially modified single chain antibody fragments (ScFv), they are not prone to adhesion or even aggregation into blocks.

Figure.1 Introduction to the Origin of Nanoantibodies^[1]

History of this part

Based on this property, researchers attempted to screen nanoantibodies that can regulate the conformation and spectral properties of GFP. Using phage display screening, they identified 7 different nanoantibodies that can bind to GFP.

After binding one of the nanoantibodies to GFP, the fluorescence increased by four times compared to eGFP itself. Later they named this nanoantibody, “Enhancer”. Structural analysis shows that in the GFP-Enhancer complex, the luminescent group carries negative charge. The binding of Enhancer with eGFP only increased fluorescence by 1.5 times, so the authors speculate that the binding of enhancer performs a function similar to the mutation of eGFP, thereby increasing fluorescence intensity. In fact, the absorption spectrum of Enhancer-GFP is similar to that of eGFP.^[2]

Reference

[1] Kourelis J, Marchal C, Posbeyikian A, Harant A, Kamoun S. NLR immune receptor-nanobody fusions confer plant disease resistance. Science. 2023 Mar 3;379(6635):934-939.
[2] Kirchhofer A, Helma J, Schmidthals K, Frauer C, Cui S, Karcher A, Pellis M, Muyldermans S, Casas-Delucchi CS, Cardoso MC, Leonhardt H, Hopfner KP, Rothbauer U. Modulation of protein properties in living cells using nanobodies. Nat Struct Mol Biol. 2010 Jan;17(1):133-8.</br> Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 151
  Illegal NgoMIV site found at 166
  
• 1000
  COMPATIBLE WITH RFC[1000]