Conveners
Biocrystallography: Signalling and Macromolecular Complexes
- Hartmut Niemann
We report the crystal structure of CRISPR-Lon, a type-III CRISPR related protease that is activated by cyclic oligoadenylates. The protein is a soluble monomer and contains a SAVED domain that accommodates cA4. Further, we show that CRISPR-Lon forms a stable complex with the 34 kDa CRISPR-T protein. Upon activation by cA4, CRISPR-Lon specifically cleaves CRISRP-T, releasing CRISPR-T23, a 23...
Type III secretion systems (T3SS) are bacterial molecular assemblies employed to inject effector proteins in host cells. We present the structure of a T3S export gate with a substrate:chaperone complex. Following a divide-and-conquer strategy, we first determined the structure of the previously uncharacterized substrate:chaperone complex at higher resolution. Our ternary complex marks the...
The TSC complex is a tumor suppressor regulating cellular growth. We investigated the structure of the TSC1 subunit and identified a coiled-coil domain that binds TSC2, a central helical domain that mediates oligomerization of TSC1 and an N-terminal domain that binds to lipids via a basic interface. These findings reveal a role of TSC1 in by mediating TSC complex membrane recruitment and...
Type VII secretion systems export proteins across the mycobacterial cell envelope into the extracellular environment. While it is still unknown how proteins cross the highly impermeable outer mycobacterial membrane, our recent cryo-EM structure has provided insights into the architecture of the base of this system- the part spanning the cytoplasmic membrane. In this presentation, this...
The bacterial transcriptional regulator RutR was shown to be lysine acetylated at five distinct sites in the DBD and LBD. However, how lysine acetylation affects RutR function is not known. Applying genetic code expansion using a synthetically evolved acetyl-lysyl-tRNA-synthetase (AcKRS3)/tRNACUA (MbPylT)-pair from Methanosarcina barkeri, we produced site-specifically lysine-acetylated...
