Structural Characterization of the Extracellular Domain of CASPR2 and Insights into Its Association with the Novel Ligand Contactin1.

Rubio-Marrero EN, Vincelli G, Jeffries CM, Shaikh TR, Pakos IS, Ranaivoson FM, von Daake S, Demeler B, De Jaco A, Perkins G, Ellisman MH, Trewhella J, Comoletti D, J Biol Chem 291(11):5788-802 (2016) Europe PMC

SASDBR2 – Contactin-associated protein-like 2 (Caspr2) extracellular domains 1-1261.

Contactin-associated protein-like 2 extracellular domains (1-1261)
MWexperimental 160 kDa
MWexpected 140 kDa
VPorod 282 nm3
log I(s) 9.84×10-1 9.84×10-2 9.84×10-3 9.84×10-4
Contactin-associated protein-like 2 extracellular domains (1-1261) small angle scattering data  s, nm-1
ln I(s)
Contactin-associated protein-like 2 extracellular domains (1-1261) Guinier plot ln 9.84×10-1 Rg: 4.4 nm 0 (4.4 nm)-2 s2
(sRg)2I(s)/I(0)
Contactin-associated protein-like 2 extracellular domains (1-1261) Kratky plot 1.104 0 √3 sRg
p(r)
Contactin-associated protein-like 2 extracellular domains (1-1261) pair distance distribution function Rg: 4.6 nm 0 Dmax: 14.5 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Contactin-associated protein-like 2 extracellular domains (1-1261) DAMMIN model
log I(s)
 s, nm-1
Contactin-associated protein-like 2 extracellular domains (1-1261) CRYSOL model
log I(s)
 s, nm-1
Contactin-associated protein-like 2 extracellular domains (1-1261) CORAL model
SAXS data were collected from solutions of contactin-associated protein-like 2 (Caspr2, amino acids 1-1261) in 10 mM HEPES 150 mM NaCl using an Anton Paar SAXSess line collimation instrument (University of Utah, USA). Scattering intensities, I(s) vs s (where s = 4π sin θ/λ, 2θ is the scattering angle, λ = 0.154 nm, CuKα) were recorded on image plates using a 10 mm slit geometry for 30 minutes (20°C sample temperature). A 10 mm integration width was employed to produce averaged 1D-smeared data that were corrected for beam intensity and beam geometry to generate the 1D-desmeared SAXS data for this entry. Different solute concentrations were measured in the range of 1.9-9.6 mg/ml. The data, P(r) vs r, ab initio bead model and rigid-body models shown above report the results obtained for the 7.7 mg/ml sample ('0.80' dilution.) All additional data, including the desmeared data for the diltution series (1, 0.8, 0.6, 0.4 and 0.2), the P(r) vs r calculated using GNOM and GIFT as well as all DAMMIN, DAMMIF (ab initio) and CORAL rigid-body models are included in the full-entry.zip archive. Both CRYSOL and CORAL fits to the data for the rigid-body models are included. Note: although one Caspr2 model is presented above, the protein likely samples several conformational states in solution as evidenced by the variation in the models generated during the course of ab initio and rigid-body modelling (refer to the full-entry archive).

Contactin-associated protein-like 2 extracellular domains (1-1261) (Caspr2)
Mol. type   Protein
Organism   Homo sapiens
Olig. state   Monomer
Mon. MW   140.4 kDa
 
UniProt   Q9UHC6 (1-1261)
Sequence   FASTA
 
ALPHAFOLD ID   Q9UHC6