Sarcin/ricin

Iordanov, M. S. et al. Ribotoxic stress response Activation of the stress-activated protein kinase JNK1 by inhibitors of the peptidyl transferase reaction and by sequence-specific RNA damage to the alpha-sarcin/ricin loop in the 28S rRNA. Mol. Cell. Biol. 17, 3373, 1997. 

Fig. 3 Secondary structure of the ribosomal rRNA of Saccharomyces cerevisiae. http //www.ma.icmb.utexas. edu (Cannone et al. 2002). The numbering of nucleotides is according to E. coli. Helices H) discussed in the text are highlighted and localization of yeast rdn mutations are indicated, a Secondary structure of the small subunit 18S rRNA. Helices discussed in the text are labeled in red. b Secondary structure of the 25 rRNA. Helices discussed in the text are labeled in blue. Helix 44 is part of the L7/L12 stalk hehx 95 contains the sarcin-ricin loop. For details, see text...

Liu R, Liebman SW (1996) A translational fidelity mutation in the universally conserved sarcin/ricin domain... 

Panopoulos P, Dresios J, Synetos D (2004) Biochemical evidence of translational infidelity and decreased peptidyltransferase activity by a sarcin/ricin domain mutation of yeast 25S rRNA. Nucleic Acids Res... 

Specific metal ion binding sites are directly observed in the crystal structures of hammerhead ribozymes [18], P4—P6 domain of Tetrahymena group I intron [19], transfer (tRNA) [20], GAAA tetraloop receptor [21], sarcin-ricin loop [22], and MMTV pseudoknots [23], for example. High... 

Chan, Y.L., Correll, C.C. and Wool, I.G. (2004) The location and the significance of a cross-link between the sarcin/ricin domain of ribosomal RNA and the elongation factor-G. J Mol Biol, 331, 263-272. 

Chen, C., Jiang, L., Michalczyk, R. and Russu, LM. (2006) Structural energetics and base-pair opening dynamics in sarcin-ricin domain RNA. Biochemistry, 45, 13606-13613. 

Mansouri, S., NouroUahzadeh, E. and Hudak, K.A. (2006) Pokeweed antiviral protein depurinates the sarcin/ricin loop of the rRNA prior to binding of aminoacyl-tRNA to the ribosomal A-site. RNA, 12, 1683-1692. 

The ricin A-chain contains an enzymatically active site that recognizes and binds a highly conserved region in the large 28S rRNA of the intoxicated cell, referred to as the sarcin/ricin loop (Rajamohan et al.. 

Rajamohan, R, Mao, C., Uckun, EM., 2001. Binding interactions between the active center cleft of recombinant pokeweed antiviral protein and the alpha-sarcin/ricin stem loop of ribosomal RNA. J. Biol. Chem. 276, 24075-24081. 

Figure 1 GAGA tetraloop extracted form the sarcin-ricin loop, (a) Secondary structure of the tetraloop. The backbone connectivity is shown with thin lines, the canonical pairing with a thick line, and the non-canonical piairing with a thin dotted line. Only the last canonical base pair of the stem is shown, (b) Stereoview of one of the NMR spectroscopy three-dimensional structures. The Cu Gig Watson-Crick base pair is shown in blue. The non-canonical A G base pair is shown in green...

The toxins or-sarcin and ricin inactivate ribosomes by altering a highly conserved sequence in 23S-like rRNAs (the sarcin-ricin loop). Elongation factors Tu and G bind near this loop, suggesting that it is involved in AA-tRNA selection and translocation. Protein L6 and the sarcin-ricin loop are involved in translational accuracy control, as suggested by the mutations in these components that... 

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