The crystal structure of the EspB-EspK virulence factor-chaperone complex suggests an additional type VII secretion mechanism in M. tuberculosis.

Gijsbers A, Eymery M, Gao Y, Menart I, Vinciauskaite V, Siliqi D, Peters PJ, McCarthy A, Ravelli RBG, J Biol Chem :102761 (2022) Europe PMC

SASDMG7 – ESX-1 secretion-associated protein EspB large construct bound to ESX-1 secretion-associated protein EspK — EspBL-K complex

ESX-1 secretion-associated protein EspK
ESX-1 secretion-associated protein EspB
MWexperimental 72 kDa
MWexpected 75 kDa
VPorod 128 nm3
log I(s) 4.06×10-2 4.06×10-3 4.06×10-4 4.06×10-5
ESX-1 secretion-associated protein EspK ESX-1 secretion-associated protein EspB small angle scattering data  s, nm-1
ln I(s)
ESX-1 secretion-associated protein EspK ESX-1 secretion-associated protein EspB Guinier plot ln 4.07×10-2 Rg: 5.0 nm 0 (5.0 nm)-2 s2
(sRg)2I(s)/I(0)
ESX-1 secretion-associated protein EspK ESX-1 secretion-associated protein EspB Kratky plot 1.104 0 3 sRg
p(r)
ESX-1 secretion-associated protein EspK ESX-1 secretion-associated protein EspB pair distance distribution function Rg: 5.2 nm 0 Dmax: 18.3 nm

Data validation


There are no models related to this curve.

Synchrotron SAXS data from solutions of the EspBL-K complex in 20 mM Tris-HCl, 300 mM NaCl, pH 8 were collected on the B21 beam line at the Diamond Light Source (Didcot, UK) using a Pilatus 2M detector at a sample-detector distance of 4.0 m and at a wavelength of λ = 0.1 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 50.00 μl sample at 4.3 mg/ml was injected onto a Shodex KW403 column at 20°C. 580 successive 3 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 sample consists of a complex between EspB (large construct, amino acids 2–460) with the C-terminal region of EspK (amino acids 484–729). The SEC-eluted protein complex was directed through a 1.6-mm diameter quartz capillary cell held in vacuum.

ESX-1 secretion-associated protein EspK (EspK(484-729))
Mol. type   Protein
Organism   Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)
Olig. state   Monomer
Mon. MW   27.2 kDa
 
UniProt   P9WJC1 (484-729)
Sequence   FASTA
 
ESX-1 secretion-associated protein EspB (EspBL(2-460))
Mol. type   Protein
Organism   Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)
Olig. state   Monomer
Mon. MW   47.8 kDa
 
UniProt   P9WJD9 (2-460)
Sequence   FASTA