EC Number   |
General Information |
Reference |
|---|
   3.6.5.4 | evolution |
co-evolution of two GTPases enables efficient protein targeting in an RNA-less chloroplast signal recognition particle pathway |
757189 |
| 3.6.5.4 | evolution |
SR ribosome binding is evolutionarily conserved |
757758 |
| 3.6.5.4 | evolution |
SR ribosome binding is evolutionarily conserved. Unlike the ribosome-binding activity of human SRalpha, CtSRalpha is unable to destabilize the interaction between protein translocase subunit Sec61beta and the Sec translocase-associated endoplasmic reticulum membrane protein Sec62, suggesting that this interaction is specific to higher eukaryotes |
-, 757758 |
| 3.6.5.4 | evolution |
the signal recognition particle receptor SRbeta belongs to the Ras-family of small monomeric GTPases, specific differences to the Arf and Sar1 families with implications for GTPase regulation are determined, overview. SRbeta is the oldest member of all small GTPases branching first in eukaryotic evolution |
-, 758481 |
| 3.6.5.4 | malfunction |
asymmetries in the catalytic center affect GTP hydrolysis, overview |
758489 |
| 3.6.5.4 | malfunction |
deletion of the finger loop abolishes loading of the cpSRP cargo, light-harvesting chlorophyll binding protein |
756198 |
| 3.6.5.4 | malfunction |
deletion of the N-terminal transmembrane domain of SRbeta does not effect receptor dimerization but reveals a cryptic translocation signal that overlaps the GTPase domain. Deletion of the G-1 region, (SRbetaD5) which comprises part of the SRbeta GTPase domain, abolishes binding to SRalpha. A mutant SRbeta containing an amino acid substitution allows the GTPase domain to bind XTP dimerizes with SRalpha most efficiently in the presence of XTP or XDP, but not ATP |
757430 |
| 3.6.5.4 | malfunction |
in contrast to the Sec61beta-SRalpha cross-link species, which increase in abundance when SR is added to EKRMs (membranes stripped of ribosomes with EDTA and high salt), most other Sec61beta-derived cross-linked adducts are reduced, in particular, the cross-link between Sec61beta and Sec62. A mutant SRP receptor, which contains only the SRX domain of SRalpha (SRalpha126/betaDN), shows a much weaker reduction in Sec61beta-Sec62 crosslinking |
757758 |
| 3.6.5.4 | metabolism |
in prokaryotic cells, the signal recognition particle consists of a SRP54 protein or Ffh and a 4.5S SRP RNA. Ffh contains a methionine-rich M domain, which binds the SRP RNA and the signal sequence on the translating ribosome. In addition, an NG domain in Ffh, comprising a GTPase G domain and a four-helix bundle N domain, forms a tight complex with a highly homologous NG domain in the SRP receptor, called FtsY in bacteria, in the presence of GTP. GTP hydrolysis at the end of the signal recognition particle cycle drives the disassembly of the Ffh-FtsY GTPase complex. The assembly of the signal recognition particle-FtsY GTPase complex and its GTPase activation require discrete conformational rearrangements in the signal recognition particle that are regulated by the RNC and the target membrane, respectively, thus ensuring the spatial and temporal precision of these molecular events during protein targeting, function of SRP RNA during co-translational protein targeting, overiew |
734245 |
| 3.6.5.4 | metabolism |
two distinct pathways deliver secretory proteins to the Sec61 protein translocase in the endoplasmic reticulum (ER) membrane. The canonical pathway requires the signal recognition particle (SRP) and its cognate receptor (SR), and targets ribosome-associated proteins to the Sec translocase. The SRP-independent pathway requires the Sec translocase-associated ER membrane protein Sec62 and can be uncoupled from translation. SR switches translocons to SRP-dependent translocation by displacing Sec62. This activity localizes to the charged linker region between the longin and GTPase domains of SRalpha. A second pathway promotes ribosome binding and is conserved between all eukaryotes. These specific regions in SRalpha reprogramme the Sec translocon and facilitate recruitment of ribosome-nascent chain complexes |
757758 |
