Structural and functional insights into peptidoglycan access for the lytic amidase LytA of Streptococcus pneumoniae.

Mellroth P, Sandalova T, Kikhney A, Vilaplana F, Hesek D, Lee M, Mobashery S, Normark S, Svergun D, Henriques-Normark B, Achour A, MBio 5(1):e01120-13 (2014) Europe PMC

SASDBF4 – Wild-type LytA (N-His6) with choline

Lytic Amidase with choline
MWI(0) 66 kDa
MWexpected 75 kDa
VPorod 115 nm3
log I(s) 7.79×101 7.79×100 7.79×10-1 7.79×10-2
Lytic Amidase with choline small angle scattering data  s, nm-1
ln I(s)
Lytic Amidase with choline Guinier plot ln 7.79×101 Rg: 4.9 nm 0 (4.9 nm)-2 s2
Lytic Amidase with choline Kratky plot 1.104 0 3 sRg
Lytic Amidase with choline pair distance distribution function Rg: 5.0 nm 0 Dmax: 15 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Lytic Amidase with choline SASREF model

log I(s)
 s, nm-1
Lytic Amidase with choline DAMMIF model

Synchrotron SAXS data from solutions of Wild-type LytA (N-His6) with choline in 20 mM Tris 150 mM NaCl 5 mM choline chloride 1 ┬ÁM ZnCl2, pH 7.5 were collected on the EMBL X33 beam line at the DORIS III storage ring (Hamburg, Germany) using a Pilatus 1M-W detector at a sample-detector distance of 2.7 m and at a wavelength of λ = 0.15 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). Solute concentrations ranging between 1 and 5 mg/ml were measured at 10°C. Eight successive 15 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. The low angle data collected at lower concentrations were extrapolated to infinite dilution and merged with the higher concentration data to yield the final composite scattering curve.

The full-length LytA dimer adopts a rigid V-shaped scaffold with the two amidase domains in the trans configuration.

Lytic Amidase with choline (wt-LytA-His6)
Mol. type   Protein
Organism   Streptococcus pneumoniae
Olig. state   Dimer
Mon. MW   37.4 kDa