Direct localization of detergents and bacteriorhodopsin in the lipidic cubic phase by small-angle neutron scattering

Cleveland IV T, Blick E, Krueger S, Leung A, Darwish T, Butler P, IUCrJ 8(1) (2021) DOI

SASDJD4 – Bacteriorhodopsin solubilized in contrast-matched octyl glucoside

MWexperimental 33 kDa
MWexpected 27 kDa
VPorod 68 nm3
log I(s) 1.73×10-1 1.73×10-2 1.73×10-3 1.73×10-4
Bacteriorhodopsin small angle scattering data  s, nm-1
ln I(s)
Bacteriorhodopsin Guinier plot ln 1.74×10-1 Rg: 2.7 nm 0 (2.7 nm)-2 s2
Bacteriorhodopsin Kratky plot 1.104 0 3 sRg
Bacteriorhodopsin pair distance distribution function Rg: 2.0 nm 0 Dmax: 5.4 nm

Data validation

There are no models related to this curve.

Small-angle neutron scattering (SANS) data from a solution of Bacteriorhodopsin (bR) at a concentration of 1.68 mg/mL measured at 22°C. Protein was solubilized in an octyl glucoside (OG) detergent mixture consisting of 21.8 mM fully deuterated OG, 14.6 mM tail-deuterated OG, and 3.6 mM non-deuterated OG (40 mM total OG). This contrast-matched OG mixture (cmOG) is designed so that the average scattering length density of the headgroup and tail layers is about 6.4 * 10^(-6) Å^(-2), i.e. matched to 100% D2O. The sample buffer consisted of 25 mM Sodium Phosphate, 1.35 mM potassium phosphate, and 40 mM cmOG in 100% D2O. Data were collected on the NGB30 SANS instrument at the NIST Center for Neutron Research (Gaithersburg, MD, USA) using a 640x640 mm 3He position sensitive Ordela 2660N detector at wavelength of λ = 0.6 nm (I(s) vs s, where s = 4πsinθ/λ and 2θ is the scattering angle). The data were normalized to the intensity of the transmitted beam and radially averaged; the constant incoherent scattering background was determined from the scattering at high angle (s > 4.5 nm^(-1)) and was subtracted. Three detector positions (in m) and count times (s) were employed: 1.33 m (one frame of 300 s total count time); 4 m (one frame of 2160 s total count time); 13.17 m (one frame of 600 s total count time). Access to NGB30 was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. Reduced scattering data in its original format, without any subtractions, is also provided in a downloadable archive. This data is in NIST 6-column format and can be displayed in, for example, the software SasView. These data also include an estimate of the Q-dependent instrument resolution, which can be used during model fitting to smear calculated SANS intensity curves. In addition, detergent-only scattering data from a panel of 31 detergent conditions is included in the archive, as well as a spreadsheet containing full details of the sample conditions.

Bacteriorhodopsin (bR)
Mol. type   Protein
Organism   Halobacterium salinarum
Olig. state   Monomer
Mon. MW   26.9 kDa
UniProt   P02945 (14-262)
Sequence   FASTA