2′-Phosphate cyclase activity of RtcA: A potential rationale for the operon organization of RtcA with an RNA repair ligase RtcB in Escherichia coli and other bacterial taxa Journal Article
| Authors: | Das, U.; Shuman, S. |
| Article Title: | 2′-Phosphate cyclase activity of RtcA: A potential rationale for the operon organization of RtcA with an RNA repair ligase RtcB in Escherichia coli and other bacterial taxa |
| Abstract: | RNA terminal phosphate cyclase catalyzes the ATP-dependent conversion of a 3′-phosphate RNA end to a 2′,3′-cyclic phosphate via covalent enzyme-(histidinyl-Nε)-AMP and RNA(3′)pp(5′)A intermediates. Here, we report that Escherichia coli RtcA (and its human homolog Rtc1) are capable of cyclizing a 2′-phosphate RNA end in high yield. The rate of 2′-phosphate cyclization by RtcA is five orders of magnitude slower than 3′-phosphate cyclization, notwithstanding that RtcA binds with similar affinity to RNA3′p and RNA2′p substrates. These findings expand the functional repertoire of RNA cyclase and suggest that phosphate geometry during adenylate transfer to RNA is a major factor in the kinetics of cyclization. RtcA is coregulated in an operon with an RNA ligase, RtcB, that splices RNA 5′-OH ends to either 3′-phosphate or 2′,3′-cyclic phosphate ends. Our results suggest that RtcA might serve an end healing function in an RNA repair pathway, by converting RNA 2′-phosphates, which cannot be spliced by RtcB, to 2′,3′- cyclic phosphates that can be sealed. The rtcBA operon is controlled by the σ54 coactivator RtcR encoded by an adjacent gene. This operon arrangement is conserved in diverse bacterial taxa, many of which have also incorporated the RNA-binding protein Ro (which is implicated in RNA quality control under stress conditions) as a coregulated component of the operon. © 2013; Published by Cold Spring Harbor Laboratory Press for the RNA Society. |
| Keywords: | unclassified drug; nonhuman; protein; enzyme activity; enzyme substrate; enzyme analysis; escherichia coli; cyclization; enzyme binding; ligase; protein rna binding; rna repair; operon; protein rtcb; 2′,3′-cyclic phosphate ends; protein rtca |
| Journal Title: | RNA |
| Volume: | 19 |
| Issue: | 10 |
| ISSN: | 1355-8382 |
| Publisher: | Cold Spring Harbor Laboratory Press |
| Date Published: | 2013-10-01 |
| Start Page: | 1355 |
| End Page: | 1362 |
| Language: | English |
| DOI: | 10.1261/rna.039917.113 |
| PROVIDER: | scopus |
| PUBMED: | 23945037 |
| PMCID: | PMC3854526 |
| DOI/URL: | |
| Notes: | --- - "Export Date: 1 November 2013" - "CODEN: RNARF" - "Source: Scopus" |
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