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PMID:11179231
| Citation |
Jenkins, BD and Barkan, A (2001) Recruitment of a peptidyl-tRNA hydrolase as a facilitator of group II intron splicing in chloroplasts. EMBO J. 20:872-9 |
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| Abstract |
Group II introns are catalytic RNAs that have been proposed to be the evolutionary precursors to the spliceosome. Most group II introns require accessory factors to splice efficiently in vivo, but few such factors have been identified. We have cloned the maize nuclear gene crs2, which is required for the splicing of nine group II introns in chloroplasts. CRS2 is related to peptidyl-tRNA hydrolase enzymes. However, CRS2 expression failed to rescue an Escherichia coli pth(ts) mutant and CRS2 lacks several conserved amino acids that are important for the activity of the E.coli enzyme, indicating that it may lack peptidyl-tRNA hydrolase activity. CRS2 is localized to the chloroplast stroma, where it is found in a large salt-stable complex that contains RNA. CRS2 co-sediments with group II intron RNA during centrifugation of stroma through sucrose gradients, suggesting that CRS2 facilitates splicing via direct interaction with intron RNA. Sequence comparisons indicate how evolutionary tinkering may have allowed an enzyme that interacts with peptidyl-tRNAs to acquire a function in group II intron splicing. |
| Links |
PubMed PMC145411 Online version:10.1093/emboj/20.4.872 |
| Keywords |
Amino Acid Sequence; Base Sequence; Carboxylic Ester Hydrolases/chemistry; Carboxylic Ester Hydrolases/genetics; Carboxylic Ester Hydrolases/metabolism; Chloroplasts/genetics; Cloning, Molecular; DNA, Plant; Introns; Molecular Sequence Data; Plant Proteins; RNA Splicing; Sequence Homology, Amino Acid |
| edit table |
Significance
Annotations
| Gene product | Qualifier | GO Term | Evidence Code | with/from | Aspect | Extension | Notes | Status |
|---|---|---|---|---|---|---|---|---|
| GO:0009570: chloroplast stroma |
ECO:0000314: |
C |
Figure 3c: Immunoblots of chloroplast subfractions showed that CRS2 is found predominantly in the chloroplast stroma. |
complete | ||||
| GO:0030529: ribonucleoprotein complex |
ECO:0000314: |
C |
Figure 6 a,c,d: Following sucrose gradient sedimentation of crude stroma, essentially all of the CRS2 was found in a peak that sediments more rapidly than Rubisco (550 kDa) and more slowly than ribosomes (Figure 6A, C and D). A260 profile of the +MNase gradient illustrating that ribosomes peak in fractions 18–21 (6D) |
complete | ||||
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