The Composition of SRP
Despite SRP function being analogous in all organisms, its composition varies greatly. The eukaryotic SRP is composed of six distinct polypeptides bound to an RNA molecule (the 7SL RNA), with GTPase activity. The components of the complex are:
- SRP9
- SRP14
- SRP19
- SRP54
- SRP68
- SRP72
- SRP RNA
The prokaryotic SRP is composed of one polypeptide bound to an RNA molecule (the 4.5S RNA), with GTPase activity. The components of the complex are:
- Ffh
- 4.5S RNA
Ffh is the structural and functional homolog of the SRP54 protein in eukaryotes. The 4.5S RNA shares sequence and structural homology with one domain of the larger 7S RNA.
| Crystallographic structures of representative SRPs | |||||||||
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Read more about this topic: Signal Recognition Particle
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