RNA 3'-phosphate cyclase (RtcA) catalyzes the ATP-dependent cyclization of a 3'-phosphate to form a 2',3'-cyclic phosphate at RNA termini. Cyclization proceeds through RtcA-AMP and RNA(3')pp(5')A covalent intermediates, which are analogous to intermediates formed during catalysis by the tRNA ligase RtcB. Here we present a crystal structure of Pyrococcus horikoshii RtcA in complex with a 3'-phosphate terminated RNA and adenosine in the AMP-binding pocket. Our data reveal that RtcA recognizes substrate RNA by ensuring that the terminal 3'-phosphate makes a large contribution to RNA binding. Furthermore, the RNA 3'-phosphate is poised for in-line attack on the P-N bond that links the phosphorous atom of AMP to N of His307. Thus, we provide the first insights into RNA 3'-phosphate termini recognition and the mechanism of 3'-phosphate activation by an Rtc enzyme.
Structure of RNA 3'-phosphate cyclase bound to substrate RNA.,Desai KK, Bingman CA, Cheng CL, Phillips GN Jr, Raines RT RNA. 2014 Aug 26. PMID:25161314[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑ Desai KK, Bingman CA, Cheng CL, Phillips GN Jr, Raines RT. Structure of RNA 3'-phosphate cyclase bound to substrate RNA. RNA. 2014 Aug 26. PMID:25161314 doi:http://dx.doi.org/10.1261/rna.045823.114
