Signal recognition particle RNA

He, X. P., Bataille, N., and Fried, H. M. (1994). Nuclear export of signal recognition particle RNA is a facilitated process that involves the Alu sequence domain. J. Cell Sci. 107,903-912. 

Huang, Q., S. Abdulrahman, J. Yin and C. Zwieb (2002). "Systematic site-directed mutagenesis of human protein SRP54 interactions with signal recognition particle RNA and modes of signal peptide recognition." Biochemistry A Q%) 11362-11371. 

NMR Structure Determination of a 28-Nucleotide Signal Recognition Particle RNA with Complete Relaxation Matrix Methods Using Corrected Nuclear Overhauser Effect Intensities... 

Comparative Modeling of the Three-Dimensional Structure of Signal Recognition Particle RNA... 

Comparative sequence analysis and ERNA-3D software were used to model the three-dimensional structures of several signal recognition particle RNAs. RNA secondary structures were established by allowing only phylogenetically-supported base pairs. The folding of the RNA molecules was constrained further to include a pseudoknot and a tertiary interaction. Founded by the concept that all SRP RNAs must be shaped similarly in three dimensions, helical sections were oriented coaxially where a continuous helical stack was formed in the RNA of another species. Finally, RNA helices were placed at distances that preserved the connectivity of the molecule with the smallest number of single-stranded nucleotide residues as identified from the aligned sequences. Representative models of the three-dimensional structures of an eukaryote, an archaeon, and three bacterial SRP RNAs are presented. 

The signal recognition particle (SRP) is a cytosolic ribonucleoprotein complex which binds to signal sequences of nascent membrane and secretory proteins emerging from ribosomes. The SRP consists of a 7S RNA and at least six polypeptide subunits (relative molecular masses 9, 14, 19, 54, 68, and 72 kD). It induces an elongation arrest until the nascent chain/ ribosome/SRP complex reaches the translocon at the endoplasmic reticulum (ER) membrane. 

The Alu sequence has strong homology with the 7S RNA (Table 5-4) that is part of the signal recognition particle involved in transport of newly synthesized peptide chains across the membranes of the ER (Chapter 10). Alu sequences are transcribed into hnRNA, the precursors to mRNA. Some Alu sequences are present in intervening sequences (introns)... 

Ke et al., 2004) and the signal recognition particle (SRP) M domain—4.5 S RNA complex (Batey et al., 2001) required complete denaturation in 8 M urea and refolding into the native form by slow dialysis to native conditions. Some RNAs in our experience have required extensive screening of ionic conditions, temperature protocols, and use of denaturants to find conditions that yield a near-homogeneous population. 

Batey, R. T., Sagar, M. B., and Doudna, J. A. (2001). Structural and energetic analysis of RNA recognition by a universally conserved protein from the signal recognition particle. J. Mol. Biol. 307, 229-246. 

In eukaryotes, RNA is synthesized by three RNA polymerases RNA Pol I is a nucleolar enzyme that transcribes rRNAs, RNA Pol II is located in the nucleoplasm and transcribes mRNAs and most snRNAs, RNA Pol III is also nucleoplasmic and transcribes tRNA and 5S rRNA, as well as U6 snRNA and the 7S RNA of the signal recognition particle (SRP). 

RNA polymerase III (RNA Pol III) is also located in the nucleoplasm. It transcribes the genes for tRNA, 5S rRNA, U6 snRNA, and the 7S RNA associated with the signal recognition particle (SRP) involved in the translocation of proteins across the endoplasmic reticulum membrane (see Topic H4). 

The mRNA for the secretory protein binds to a free cytoplasmic ribosome and protein synthesis begins. The first part of the protein made is the N-terminal signal peptide. A signal recognition particle (SRP), which is a complex of a 7S RNA and six proteins, binds to the signal peptide and stops further protein synthesis. This stops the secretory protein from being released prematurely into the cytosol. The ribosome-mRNA-SRP complex now binds to an SRP receptor, a protein on the surface of the ER. The ER membrane also contains a ribosome receptor protein associated with a protein translocator. In a concerted series of reactions, the ribosome is held tightly by the ribosome receptor protein, the SRP... 

Archaea contain a stable 7S RNA species of unknown function, which is not associated with the ribosome. The 7S RNA gene from Halobacterium halobium NRC817 has been cloned and sequenced [120]. The sequence resembles the 7SL RNA of eucarya [85] and the 4.5S Escherichia coli) or sc Bacillus subtilis) RNAs of bacteria [121] in potential secondary structure. The 7SL RNA forms part of the signal-recognition particle, involved in protein translocation. The function of the 4.5S RNA is not known exactly, but it is known to be essential [122]. 

The signal-recognition particle (SRP) is an 11 S ribonucleoprotein composed of a 7 S RNA molecule and six nonidentical polypeptide chains (Walter and Blobel, 1983). It is viewed as functioning to couple the translation of secretory proteins to their translocation through the membrane (Walter and Blobel, 1981b). SRP is isolated from the microsomal membrane by a high-salt wash (Walter and Blobel, 1981a). It can be disassembled into its individual components, which can then be reconstituted into an active particle (Walter and Blobel, 1983). 

A small RNA molecule is an essential component of the signal-recognition particle, an RNA protein complex in the cytoplasm that helps target newly synthesized proteins to intracellular compartments and extracellular destinations. 

Figure 30.30 The signal-recognition particle. The signal-recognition particle (SRP) consists of six proteins (one of which is SRPS-I) and one 300-nucleotide R,NA molecule. The RNA has a complex structure with many double-hclicat stretches punctuated by single-stranded regions, shown as circles. [After H, Lodish et al., Molecular Cell Biology, 5th ed.

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