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RNA 3'-terminal phosphate cyclase (EC 6.5.1.4) [1,2] catalyzes the conversion of 3'-phosphate to a 2',3'-cyclic phosphodiester at the end of RNA. The biological role of this enzyme is unknown but it is likely to function in some aspects of cellular RNA processing.

The reaction catalyzed by the enzyme occurs in three steps:

 1) adenylation of the enzyme by ATP;
 2) the  enzyme  acts  on  RNA-3'terminal  phosphate to produce RNA-3'terminal
    diphosphate adenylate;
 3) Release  of  AMP and cyclisation by a non catalytic nucleophilic attack by
    the adjacent 2'hydroxyl on the phosphorus in the diester linkage.

This enzyme, which has been characterized in human (where there seems to be at least three isozymes) and Escherichia coli (gene rtCA), seems to be taxonomically widespread. It is found in insects, plants, fungi (gene RTC1 in yeast) and in archeabacteria.

RNA cyclase is a protein of from 36 to 42 Kd. The best conserved region, which we use as a signature pattern, is a glycine-rich stretch of residues located in the central part of the sequence and which is reminiscent of various ATP, GTP or AMP glycine-rich loops. In this context, the conserved Arg (His in the E.coli enzyme) could be the AMP-binding residue.

Filipowicz W.
.

November 1997 / First entry.

PROSITE method (with tools and information) covered by this documentation:

RTC, PS01287; RNA 3'-terminal phosphate cyclase signature  (PATTERN)

Consensus pattern: [RH]-G-x(2)-P-x-G(3)-x-[LIV] Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS01287 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS01287 • Scan Swiss-Prot/TrEMBL entries against PS01287 • view ligand binding statistics

Matching PDB structures: 1QMH 1QMI 3KGD 3TUT ... [ALL]

1	Authors	Genschik P., Billy E., Swianiewicz M., Filipowicz W.
	Title	The human RNA 3'-terminal phosphate cyclase is a member of a new family of proteins conserved in Eucarya, Bacteria and Archaea.
	Source	EMBO J. 16:2955-2967(1997).
	PubMed ID	9184239
	DOI	10.1093/emboj/16.10.2955

2	Authors	Filipowicz W., Vicente O.
	Title	RNA 3'-terminal phosphate cyclase from HeLa cells.
	Source	Methods Enzymol. 181:499-510(1990).
	PubMed ID	2199762

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