|PROSITE documentation PDOC00989
RNA 3'-terminal phosphate cyclase signature
RNA 3'-terminal phosphate cyclase (EC 126.96.36.199) [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
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.
November 1997 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|RTC, PS01287; RNA 3'-terminal phosphate cyclase signature (PATTERN)
|Sequences in UniProtKB/Swiss-Prot known to belong to this class detected by PS01287:
||83 true positives with 16 false negatives.
|Other sequence(s) in UniProtKB/Swiss-Prot detected by PS01287:
||2 false positives.
|Matching PDB structures:
1QMH 1QMI 3KGD 3TUT ... [ALL]
||Genschik P., Billy E., Swianiewicz M., Filipowicz W.
||The human RNA 3'-terminal phosphate cyclase is a member of a new family of proteins conserved in Eucarya, Bacteria and Archaea.
||EMBO J. 16:2955-2967(1997).
||Filipowicz W., Vicente O.
||RNA 3'-terminal phosphate cyclase from HeLa cells.
||Methods Enzymol. 181:499-510(1990).
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