What are nanoantibodies? 5th November 2021 – Tags: , , ,

What are nanoantibodies?

Many people wonder what are nanoantibodies? The nanoantibodies are a type of camelid-derived antibody, being much smaller than the usual antibodies, each of which is a conglomerate of two heavy chains and two heavy chains. ligeras, intricately folded and bound to complex sugars. In other words, the nanoantibodies are tiny recombinantly produced antigen-binding VHH fragments derived from the alpaca heavy chain IgG antibody (HCAb).

nanobodies definition

The domain VHH represents the smallest antibody fragment necessary to bind specifically to an antigen with exceptionally high affinity.

How can I use a nanoantibody?

In short, almost any shape!

Nanoantibodies come in a variety of formats. They are raised against quite a diverse range of antigens, making them very versatile tools, capable of being used in a variety of different situations.

The most common uses for nanoantibodies are experiments you are probably already familiar with, such as immunoprecipitation or fluorescence microscopy.

There are also a handful of applications where the use of a nanoantibody is feasible, but the use of a conventional antibody would be impractical or impossible.

Difference between nanoantibodies and traditional monoclonal or polyclonal antibodies

  • More consistent
  • Greater affinity
  • Easier to use

 

Nanobodies are offered in a variety of formats, including Nano-Traps, Nano-Boosters and Chromobodies®.

What is a Nano-Trap?

Nano-traps are nano-bodies which have been conjugated with agarose or magnetic beads to facilitate cleaner, faster and simpler immunoprecipitations.

Nano-traps are available in a variety of formats and target a variety of common tags, including green fluorescent protein (GFP), red fluorescent protein (RFP), Myc, GST and MBP.

Nano-traps for DNA methyltransferase (Dnmt-1), p53 and PARP-1 are also available for immunoprecipitation of unlabelled and endogenously expressed proteins.

nano-trap

Nano-traps allow you to perform IP experiments with exceptionally high throughput and without contamination of antibody heavy or light chains.

Nano-traps significantly improve on conventional IP protocols, we will see some improvements:

  • Faster (about half the time required for an antibody IP)
  • Cleaner (no contamination of heavy or light chain antibodies)
  • More consistent (recombinant reagents for the same interaction each time)
  • Higher throughput (picomolar to nanomolar affinity constants for GFP and RFP-traps®)

To facilitate greater versatility in IP methodology, all nano-traps come conjugated to agarose beads, ferromagnetic beads or agarose/magnetic beads.

Researchers in the US and Western Europe receive the GFP and RFP traps the day after purchase from antibodies-online.

What is a Nano-Booster?

Nano-Boosters use the power of the nano-body to enhance, modulate or reactivate the weak fluorescent signal of a fluorescent protein.

A Nano-Booster is composed of a nano-body, targeted to GFP or RFP, and conjugated with an ultra-bright ATTO dye.
The natural fluorescent properties of GFP are enhanced by the ultra-bright ATTO-488 dye coupled to the ABIN509419 GFP-Booster®.

ATTO dyes were specifically chosen for use with the Nano-Booster because of their exceptionally bright signal, best-in-class photostability, and narrow Stokes shift.

Next-generation imaging techniques, such as super-resolution microscopy, require bright, photostable fluorescent probes.

Nano-Boosters can provide the “signal boost” needed to make fluorescent proteins such as GFP bright and stable for super-resolution microscopy.

What is a Chromobody®?

Chromobodies® are novel tools for intracellular fluorescent labelling of living cells.

Chromobodies® are fusion proteins containing a nanobody targeting your protein of interest and a glowing, photostable fluorescent protein.

Because the nanobodies are produced from recombinant DNA, you can generate Chromobodies® directly, right inside the cell you want to tag. No cumbersome, frustrating or time-consuming fixation or labelling protocols.

Simply start with the appropriate Chromobody® plasmid, transfect it into a compatible cell line and use persistent intracellular immunolabelling in live cells.

Chromobodies® uses your own cells to produce the nanobodies that will tag your protein of interest.

Neither fixation nor additional staining steps are necessary. Finally, intracellular immunolabelling in live cells is a viable strategy.

Nanobodies structure

Nanobodies are also called single domain antibodies or VHH antibodies because they consist of only one variable domain (VHH) of the heavy chain of an antibody. Nanobodies are peptides of approximately 110 amino acids in length.

VHH domains have four framework regions (FR) and three hypervariable regions (HV) or CDR complementarity determining regions. The CDRs or HVs have a high proportion of amino acid variability at one position, and are the regions involved in antigen binding, as they come into contact with the antigen surface.

HHV has four amino acid substitutions in the FR2 region at positions 37, 44, 45, and 47. The FR2 of conventional VH does not have these substitutions and is involved in the formation of the hydrophobic interface with the VL domain.

Nanobodies applications

The main applications in which nanoantibodies are being studied are the treatment of human diseases by interacting with specific toxic enzymes or blocking molecular interactions.

In the field of oncology, HHVs are used to disrupt molecular interactions or lysis of oncogenic cells. To kill cancer cells, VHH binds to the carcinoembryonic antigen that serves as a marker for β-lactamase, turning a non-toxic prodrug into a drug that is toxic to the cancer cell.

The biotechnological application of nanoantibodies is potentially feasible, one example being antigen tagging in living cells by applying specific fluorescent nanoantibodies to endogenous proteins.

Read more in our blog