TY  - JOUR
A1  - Mietrach, Nicole
A1  - Schlosser, Andreas
A1  - Geibel, Sebastian
T1  - An extracellular domain of the EsaA membrane component of the type VIIb secretion system: expression, purification and crystallization
JF  - Acta Crystallographica Section F
N2  - The membrane protein EsaA is a conserved component of the type VIIb secretion system. Limited proteolysis of purified EsaA from Staphylococcus aureus USA300 identified a stable 48 kDa fragment, which was mapped by fingerprint mass spectrometry to an uncharacterized extracellular segment of EsaA. Analysis by circular dichroism spectroscopy showed that this fragment folds into a single stable domain made of mostly α‐helices with a melting point of 34.5°C. Size‐exclusion chromatography combined with multi‐angle light scattering indicated the formation of a dimer of the purified extracellular domain. Octahedral crystals were grown in 0.2 M ammonium citrate tribasic pH 7.0, 16% PEG 3350 using the hanging‐drop vapor‐diffusion method. Diffraction data were analyzed to 4.0 Å resolution, showing that the crystals belonged to the enantiomorphic tetragonal space groups P41212 or P43212, with unit‐cell parameters a = 197.5, b = 197.5, c = 368.3 Å, α = β = γ = 90°.
KW  - ESAT‐6‐like secretion system
KW  - ESS
KW  - type VII secretion system
KW  - EsaA
KW  - extracellular domain
KW  - Staphylococcus aureus USA300
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213681
VL  - 75
IS  - 12
ER  - 
TY  - JOUR
A1  - Jarick, Marcel
A1  - Bertsche, Ute
A1  - Stahl, Mark
A1  - Schultz, Daniel
A1  - Methling, Karen
A1  - Lalk, Michael
A1  - Stigloher, Christian
A1  - Steger, Mirco
A1  - Schlosser, Andreas
A1  - Ohlsen, Knut
T1  - The serine/threonine kinase Stk and the phosphatase Stp regulate cell wall synthesis in Staphylococcus aureus
JF  - Scientific Reports
N2  - The cell wall synthesis pathway producing peptidoglycan is a highly coordinated and tightly regulated process. Although the major components of bacterial cell walls have been known for decades, the complex regulatory network controlling peptidoglycan synthesis and many details of the cell division machinery are not well understood. The eukaryotic-like serine/threonine kinase Stk and the cognate phosphatase Stp play an important role in cell wall biosynthesis and drug resistance in S. aureus. We show that stp deletion has a pronounced impact on cell wall synthesis. Deletion of stp leads to a thicker cell wall and decreases susceptibility to lysostaphin. Stationary phase Δstp cells accumulate peptidoglycan precursors and incorporate higher amounts of incomplete muropeptides with non-glycine, monoglycine and monoalanine interpeptide bridges into the cell wall. In line with this cell wall phenotype, we demonstrate that the lipid II:glycine glycyltransferase FemX can be phosphorylated by the Ser/Thr kinase Stk in vitro. Mass spectrometric analyses identify Thr32, Thr36 and Ser415 as phosphoacceptors. The cognate phosphatase Stp dephosphorylates these phosphorylation sites. Moreover, Stk interacts with FemA and FemB, but is unable to phosphorylate them. Our data indicate that Stk and Stp modulate cell wall synthesis and cell division at several levels.
KW  - bacterial transcription
KW  - pathogens
KW  - cell wall synthesis
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177333
VL  - 8
IS  - 13693
ER  -