Solution structural studies of pre-amyloid oligomer states of the biofilm protein Aap.

Yarawsky AE, Hopkins JB, Chatzimagas L, Hub JS, Herr AB, J Mol Biol :167708 (2022) Europe PMC

SASDP83 – Accumulation-association protein (Aap) Brpt5.5 2xH85A tetramer in the presence of ZnCl2

Accumulation associated protein (mutant)
MWexperimental 282 kDa
MWexpected 312 kDa
log I(s) 8.47×10-2 8.47×10-3 8.47×10-4 8.47×10-5
Accumulation associated protein (mutant) small angle scattering data  s, nm-1
ln I(s)
Accumulation associated protein (mutant) Guinier plot ln 8.47×10-2 Rg: 15.7 nm 0 (15.7 nm)-2 s2
Accumulation associated protein (mutant) Kratky plot 1.104 0 3 sRg
Accumulation associated protein (mutant) pair distance distribution function Rg: 17.7 nm 0 Dmax: 70 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Accumulation associated protein (mutant) PYMOL model

Synchrotron SAXS data from solutions of accumulation-association protein (Aap) Brpt5.5 2xH85A tetramer in the presence of ZnCl2 in 50 mM MOPS, 50 mM NaCl, 5 mM ZnCl2, pH 7.2 were collected on the BioCAT 18ID beam line at the Advanced Photon Source (APS), Argonne National Laboratory (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). In-line size-exclusion chromatography (SEC) SAS was employed. The SEC parameters were as follows: A 275.00 μl sample at 7.1 mg/ml was injected at a 0.80 ml/min flow rate onto a GE Superose 6 Increase 10/300 column at 23°C. 2843 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.

Brpt5.5 2xH85A (G5 08 - G5 13) in the presence of 5 mM ZnCl2, which induces tetramerization. This is a mutant construct which contains a His to Ala mutation in the 85 position of spacer subdomains 09 and 11 (H213A, H469A).

Accumulation associated protein (mutant) (Aap)
Mol. type   Protein
Organism   Staphylococcus epidermidis (strain ATCC 35984 / RP62A)
Olig. state   Tetramer
Mon. MW   77.9 kDa
UniProt   Q5HKE8 (1505-2223)
Sequence   FASTA