The solution structure of the heavy chain-only C5-Fc nanobody reveals exposed variable regions that are optimal for COVID-19 antigen interactions.

Gao X, Thrush JW, Gor J, Naismith JH, Owens RJ, Perkins SJ, J Biol Chem :105337 (2023) Europe PMC

SASDSD2 – Recombinant Heavy-chain-only nanobody C5-Fc (glycosylated)

Immunoglobulin heavy constant gamma 1
MWexperimental 78 kDa
MWexpected 78 kDa
VPorod 157 nm3
log I(s) 5.14×10-2 5.14×10-3 5.14×10-4 5.14×10-5
Immunoglobulin heavy constant gamma 1 small angle scattering data  s, nm-1
ln I(s)
Immunoglobulin heavy constant gamma 1 Guinier plot ln 5.14×10-2 Rg: 3.9 nm 0 (3.9 nm)-2 s2
(sRg)2I(s)/I(0)
Immunoglobulin heavy constant gamma 1 Kratky plot 1.104 0 √3 sRg
p(r)
Immunoglobulin heavy constant gamma 1 pair distance distribution function Rg: 4.0 nm 0 Dmax: 13.2 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Immunoglobulin heavy constant gamma 1 PYMOL model
Synchrotron SEC-SAXS data from solutions of Nanobody C5-Fc Glycosylated in 20 mM L-histidine, 138 mM NaCl, and 2.6 mM KCl buffer, pH 6 were collected on the B21 beam line at the Diamond Light Source storage ring (Didcot, UK) using a Pilatus 2M detector at a sample-detector distance of 4 m and at a wavelength of λ = 0.12 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 1.0mg/ml was measured at 20°C. 30 successive 30 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.

Non-standard fit file.

Immunoglobulin heavy constant gamma 1 (C5-Fc Glycosylated)
Mol. type   Protein
Organism   Homo sapiens
Olig. state   Monomer
Mon. MW   78.4 kDa
Sequence   FASTA