A solution structure analysis reveals a bent collagen triple helix in the complement activation recognition molecule mannan-binding lectin.

Iqbal H, Fung KW, Gor J, Bishop AC, Makhatadze GI, Brodsky B, Perkins SJ, J Biol Chem 299(2):102799 (2023) Europe PMC

SASDRX2 – [(Pro-Hyp-Gly)13]3

Ac-(POG)13-NH2
MWexperimental 11 kDa
MWexpected 15 kDa
VPorod 14 nm3
log I(s) 1.19×10-2 1.19×10-3 1.19×10-4 1.19×10-5
Ac-(POG)13-NH2 small angle scattering data  s, nm-1
ln I(s)
Ac-(POG)13-NH2 Guinier plot ln 1.19×10-2 Rg: 2.8 nm 0 (2.8 nm)-2 s2
(sRg)2I(s)/I(0)
Ac-(POG)13-NH2 Kratky plot 1.104 0 √3 sRg
p(r)
Ac-(POG)13-NH2 pair distance distribution function Rg: 3.2 nm 0 Dmax: 9.5 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Ac-(POG)13-NH2 PYMOL model
Synchrotron SAXS data from solutions of (POG)13 in 20 mM L-histidine, 138 mM NaCl, 2.7 mM KCL, pH 6 were collected on the B21 beam line at the Diamond Light Source (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 1.50 mg/ml was measured at 20°C. 60 successive 1 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.

The protein is N-terminal acetylated with a C-terminal amino group.

Ac-(POG)13-NH2 ((POG)13)
Mol. type   Protein
Organism   synthetic construct
Olig. state   Trimer
Mon. MW   5.1 kDa
Sequence   FASTA