H
IPR036430

Ribonuclease T2-like superfamily

InterPro entry
Short nameRNase_T2-like_sf
Overlapping entries
 

Description

Ribonuclease T2 (RNase T2) is a widespread family of secreted RNases found in every organism examined thus far. This family includes RNase Rh, RNase MC1, RNase LE, and self-incompatibility RNases (S-RNases)
[3, 5, 4, 1, 6]
. Plant T2 RNases are expressed during leaf senescence in order to scavenge phosphate from ribonucleotides. They are also expressed in response to wounding or pathogen invasion. S-RNases are thought to prevent self-fertilization by acting as selective cytotoxins of "self" pollen. Generally, RNases have two distinct binding sites: the primary site (B1 site) and the subsite (B2 site), for nucleotides located at the 5'- and 3'- terminal ends of the sissile bond, respectively.

The fungal ribonucleases T2 from Aspergillus oryzae, M from Aspergillus saitoi and Rh from Rhizopus niveus are structurally and functionally related 30 Kd glycoproteins
[2]
that cleave the 3'-5' internucleotide linkage of RNA via a nucleotide 2',3'-cyclic phosphate intermediate (
3.1.27.1
). Two histidines residues have been shown
[8, 7]
to be involved in the catalytic mechanism of RNase T2 and Rh. These residues and the region around them are highly conserved in a number of other RNAses that have been found to be evolutionary related to these fungal enzymes.

The structure of ribonuclease T2 is composed of an α+β fold.

References

1.Crystal structures of the ribonuclease MC1 mutants N71T and N71S in complex with 5'-GMP: structural basis for alterations in substrate specificity. Numata T, Suzuki A, Kakuta Y, Kimura K, Yao M, Tanaka I, Yoshida Y, Ueda T, Kimura M. Biochemistry 42, 5270-8, (2003). View articlePMID: 12731868

2.Primary structure of a base non-specific and adenylic acid preferential ribonuclease from Aspergillus saitoi. Watanabe H, Naitoh A, Suyama Y, Inokuchi N, Shimada H, Koyama T, Ohgi K, Irie M. J. Biochem. 108, 303-10, (1990). View articlePMID: 2229029

3.Ribonucleases from T2 family. Deshpande RA, Shankar V. Crit. Rev. Microbiol. 28, 79-122, (2002). PMID: 12109772

4.Crystal structure of a ribonuclease from the seeds of bitter gourd (Momordica charantia) at 1.75 A resolution. Nakagawa A, Tanaka I, Sakai R, Nakashima T, Funatsu G, Kimura M. Biochim. Biophys. Acta 1433, 253-60, (1999). View articlePMID: 10446375

5.Ribonuclease T2. Irie M, Ohgi K. Meth. Enzymol. 341, 42-55, (2001). View articlePMID: 11582795

6.Characterization of Rny1, the Saccharomyces cerevisiae member of the T2 RNase family of RNases: unexpected functions for ancient enzymes? MacIntosh GC, Bariola PA, Newbigin E, Green PJ. Proc. Natl. Acad. Sci. U.S.A. 98, 1018-23, (2001). View articlePMID: 11158587

7.Crystal and molecular structure of RNase Rh, a new class of microbial ribonuclease from Rhizopus niveus. Kurihara H, Mitsui Y, Ohgi K, Irie M, Mizuno H, Nakamura KT. FEBS Lett. 306, 189-92, (1992). View articlePMID: 1633875

8.Identification of two essential histidine residues of ribonuclease T2 from Aspergillus oryzae. Kawata Y, Sakiyama F, Hayashi F, Kyogoku Y. Eur. J. Biochem. 187, 255-62, (1990). View articlePMID: 2298207

GO terms

biological process

  • None

cellular component

  • None

Cross References

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