Sas20 is a highly flexible starch-binding protein in the Ruminococcus bromii cell-surface amylosome

Cerqueira F, Photenhauer A, Doden H, Brown A, Abdel-Hamid A, Moraïs S, Bayer E, Wawrzak Z, Cann I, Ridlon J, Hopkins J, Koropatkin N, Journal of Biological Chemistry :101896 (2022) DOI

SASDMY9 – Dockerin domain-containing protein, starch adherence system 20 (Sas20), domain 2

Dockerin domain-containing protein

MW^experimental	26	kDa
MW^expected	26	kDa
V^Porod	35	nm³

log I(s) 8.28×10^-2 8.28×10^-3 8.28×10^-4 8.28×10^-5

Dockerin domain-containing protein small angle scattering data

s, nm^-1

Log plot Log-Log plot

ln I(s)

Dockerin domain-containing protein Guinier plot

ln 8.28×10^-2 R_g: 2.3 nm 0 (2.3 nm)^-2 s²

(sR_g)²I(s)/I(0)

Dockerin domain-containing protein Kratky plot

1.104 0 √3 sR_g

p(r)	R_g: 2.3 nm 0 D_max: 7.8 nm

Data validation

Experimental data range

p(r) fit to data

Metric

Value

s_min D_max / π

0.2

N_Shannon

Worse

Better

Metric

Value

p_cormap

χ²

0.036
-1

Worse

Better

Fits and models

log I(s)	s, nm^-1
+3 Δ/σ -3	s, nm^-1

Dockerin domain-containing protein MULTIFOXS model

Synchrotron SAXS data from solutions of Dockerin domain-containing protein, starch adherence system 20 (Sas20), domain 2 in phosphate buffered saline, 1 mM TCEP, pH 7 were collected on the BioCAT 18ID beam line at the Advanced Photon Source (APS), Argonne National Laboratory storage ring (Lemont, IL, USA) using a Pilatus3 X 1M detector at a sample-detector distance of 3.6 m and at a wavelength of λ = 0.1033 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 17.00 mg/ml was measured at 23°C. 2500 successive 0.500 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.

Dockerin domain-containing protein (Doc20)
Mol. type		Protein
Organism		Ruminococcus bromii
Olig. state		Monomer
Mon. MW		26.5 kDa

UniProt		A0A2N0URA4 (311-556)
Sequence		FASTA