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RNA. 2014 Oct;20(10):1560-6. doi: 10.1261/rna.045823.114. Epub 2014 Aug 26.

Structure of RNA 3'-phosphate cyclase bound to substrate RNA.

Author information

1
Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
2
Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA BioSciences at Rice and Department of Chemistry, Rice University, Houston, Texas 77005, USA.
3
Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA rtraines@wisc.edu.

Abstract

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(ε) 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.

KEYWORDS:

2′,3′-cyclic phosphate termini; RNA 3′-phosphate termini; RtcA

PMID:
25161314
PMCID:
PMC4174438
DOI:
10.1261/rna.045823.114
[Indexed for MEDLINE]
Free PMC Article

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