Decoupling of size and shape fluctuations in heteropolymeric sequences reconciles discrepancies in SAXS vs. FRET measurements.

Fuertes G, Banterle N, Ruff KM, Chowdhury A, Mercadante D, Koehler C, Kachala M, Estrada Girona G, Milles S, Mishra A, Onck PR, Gräter F, Esteban-Martín S, Pappu RV, Svergun DI, Lemke EA, Proc Natl Acad Sci U S A 114(31):E6342-E6351 (2017) Europe PMC

SASDER2 – Unlabeled Importin Beta Binding domain (IBB) from importin subunit alpha-1 without denaturant

Importin subunit alpha-1
MWexperimental 17 kDa
MWexpected 11 kDa
VPorod 30 nm3
log I(s) 1.16×103 1.16×102 1.16×101 1.16×100
Importin subunit alpha-1 small angle scattering data  s, nm-1
ln I(s)
Importin subunit alpha-1 Guinier plot ln 1.16×103 Rg: 3.2 nm 0 (3.2 nm)-2 s2
(sRg)2I(s)/I(0)
Importin subunit alpha-1 Kratky plot 1.104 0 3 sRg
p(r)
Importin subunit alpha-1 pair distance distribution function Rg: 3.2 nm 0 Dmax: 11.5 nm

Data validation


Fits and models


log I(s)
 s, nm-1
Unlabeled Importin Beta Binding domain (IBB) from importin subunit alpha-1 without denaturant Rg histogram Rg, nm
Importin subunit alpha-1 OTHER model
Importin subunit alpha-1 OTHER model
Importin subunit alpha-1 OTHER model
Importin subunit alpha-1 OTHER model

Synchrotron SAXS data from solutions of Unlabeled Importin Beta Binding domain (IBB) from importin subunit alpha-1 without denaturant in PBS, 10 mM DTT, pH 7.4 were collected on the EMBL P12 beam line at the PETRA III storage ring (Hamburg, Germany) using a Pilatus 2M detector at a sample-detector distance of 3 m and at a wavelength of λ = 0.1 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). Solute concentrations ranging between 1 and 5 mg/ml were measured at 23°C. 20 successive 0.050 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 low angle data collected at lower concentration were merged with the highest concentration high angle data to yield the final composite scattering curve.

The protein contains a penultimate non-canonical amino acid p-acetylphenylalanine (207 Da) that is represented as U (selenocysteine, 168 Da) in the amino acid sequence for the entry. Therefore, the calculated MW from sequence (MW(expected)) must be adjusted accordingly (ca. 40 Da).

Tags: idp
Importin subunit alpha-1 (IBB)
Mol. type   Protein
Organism   Homo sapiens
Olig. state   Monomer
Mon. MW   11.3 kDa
 
UniProt   P52292 (3-97)
Sequence   FASTA