A Structural Basis for Inhibition of the Complement Initiator Protease C1r by Lyme Disease Spirochetes.

Garrigues RJ, Powell-Pierce AD, Hammel M, Skare JT, Garcia BL, J Immunol 207(11):2856-2867 (2021) Europe PMC

SASDKX7 – CCP2-SP domains of the complement C1r subcomponent bound to the complement inhibitory domain of the Borrelia burgdorferi fibronectin-binding protein BBK32

Fibronectin-binding protein BBK32
Complement C1r subcomponent
MWexperimental 56 kDa
MWexpected 55 kDa
VPorod 75 nm3
log I(s) 1.98×101 1.98×100 1.98×10-1 1.98×10-2
Fibronectin-binding protein BBK32 Complement C1r subcomponent small angle scattering data  s, nm-1
ln I(s)
Fibronectin-binding protein BBK32 Complement C1r subcomponent Guinier plot ln 1.98×101 Rg: 2.8 nm 0 (2.8 nm)-2 s2
(sRg)2I(s)/I(0)
Fibronectin-binding protein BBK32 Complement C1r subcomponent Kratky plot 1.104 0 3 sRg
p(r)
Fibronectin-binding protein BBK32 Complement C1r subcomponent pair distance distribution function Rg: 2.8 nm 0 Dmax: 8.6 nm

Data validation


Fits and models


log I(s)
 s, nm-1
Fibronectin-binding protein BBK32 Complement C1r subcomponent PYMOL model

Synchrotron SAXS data from solutions of the complex formed between the CCP2-SP domains of the complement C1r subcomponent and the complement inhibitory domain of the Borrelia burgdorferi fibronectin-binding protein BBK32 in 10 mM HEPES, pH 7.3,140 mM NaCl, were collected on the 12.3.1 (SIBYLS) beam line at the Advanced Light Source (ALS; Berkeley, CA, USA) using a Pilatus3 X 2M detector at a sample-detector distance of 2.1 m and at a wavelength of λ = 0.1127 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 55.00 μl sample at 2 mg/ml was injected at a 0.50 ml/min flow rate onto a Shodex KW-802.5 column at 20°C. 3 second X-ray exposures were collected continuously during the entire 30 min elution. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted from the appropriate sample peak frames.

The beam line is equipped with an online Agilent 1260 Infinity HPLC system with a series of UV at 280 and 260 nm, multi-angle light scattering (MALS), quasi-elastic light scattering (QELS), and refractometer detectors. MALS experiments were performed using an 18-angle DAWN HELEOS II light scattering detector connected in tandem to an Optilab refractive index concentration detector (Wyatt Technology).

Fibronectin-binding protein BBK32 (BBK32)
Mol. type   Protein
Organism   Borrelia burgdorferi (strain ATCC 35210 / B31 / CIP 102532 / DSM 4680)
Olig. state   Monomer
Mon. MW   16.9 kDa
 
UniProt   O50835 (206-348)
Sequence   FASTA
 
Complement C1r subcomponent (C1r)
Mol. type   Protein
Organism   Homo sapiens
Olig. state   Monomer
Mon. MW   37.7 kDa
 
UniProt   P00736 (376-705)
Sequence   FASTA