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The fungal ribonucleases T2 from Aspergillus oryzae, M from Aspergillus saitoi and Rh from Rhizopeus niveus are structurally and functionally related 30 Kd glycoproteins [1] that cleave the 3'-5' internucleotide linkage of RNA via a nucleotide 2',3'-cyclic phosphate intermediates (EC 3.1.27.1).

A number of other RNAses have been found to be evolutionary related to these fungal enzymes:

• Self-incompatibility [2] in flowering plants is often controlled by a single gene (S-gene) that has several alleles. This gene prevents fertilization by self-pollen or by pollen bearing either of the two S- alleles expressed in the style. The self-incompatibility glycoprotein from several higher plants of the solanaceae family has been shown [2,3] to be a ribonuclease.
• Phosphate-starvation induced RNAses LE and LX from tomato [4]. These two enzymes are probably involved in a phosphate-starvation rescue system.
• Escherichia coli periplasmic RNAse I (EC 3.1.27.6) (gene rna) [5].
• Aeromonas hydrophila periplasmic RNAse.
• Haemophilus influenzae hypothetical protein HI0526.

Two histidines residues have been shown [6,7] to be involved in the catalytic mechanism of RNase T2 and Rh. These residues and the region around them are highly conserved in all the sequence described above. We have developed two signature patterns, one for each of the two active-site histidines. The second pattern also contains a cysteine which is known to be involved in a disulfide bond.

April 2006 / Pattern revised.

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

RNASE_T2_1, PS00530; Ribonuclease T2 family histidine active site 1  (PATTERN)

Consensus pattern: [FYWL]-x-[LIVM]-H-G-L-[WY]-P H is an active site residue 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 PS00530 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00530 • Scan Swiss-Prot/TrEMBL entries against PS00530 • view ligand binding statistics

Matching PDB structures: 1BK7 1BOL 1DIX 1IOO ... [ALL]

RNASE_T2_2, PS00531; Ribonuclease T2 family histidine active site 2  (PATTERN)

Consensus pattern: [LIVMF]-x(2)-[HDGTY]-[EQ]-[FYW]-x-[KRT]-H-[GA]-x-C H is an active site residue; C is involved in a disulfide bond Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: genome polyproteins from Bovine viral diarrhea virus and Hog cholera virus. It seems that these pestiviruses polyproteins include a RNAse T2-like domain [8].

• 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 PS00531 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00531 • Scan Swiss-Prot/TrEMBL entries against PS00531 • view ligand binding statistics

Matching PDB structures: 1BK7 1BOL 1DIX 1J1F ... [ALL]

1	Authors	Watanabe H., Naitoh A., Suyama Y., Inokuchi N., Shimada H., Koyama T., Ohgi K., Irie M.
	Title	Primary structure of a base non-specific and adenylic acid preferential ribonuclease from Aspergillus saitoi.
	Source	J. Biochem. 108:303-310(1990).
	PubMed ID	2229029

2	Authors	Haring V., Gray J.E., McClure B.A., Anderson M.A., Clarke A.E.
	Title	Self-incompatibility: a self-recognition system in plants.
	Source	Science 250:937-941(1990).
	PubMed ID	2237440

3	Authors	McClure B.A., Haring V., Ebert P.R., Anderson M.A., Simpson R.J., Sakiyama F., Clarke A.E.
	Title	Style self-incompatibility gene products of Nicotiana alata are ribonucleases.
	Source	Nature 342:955-957(1989).
	PubMed ID	2594090
	DOI	10.1038/342955a02296281

4	Authors	Loeffler A., Glund K., Irie M.
	Source	Eur. J. Biochem. 214:627-633(1993).

5	Authors	Meador J. III, Kennell D.
	Title	Cloning and sequencing the gene encoding Escherichia coli ribonuclease I: exact physical mapping using the genome library.
	Source	Gene 95:1-7(1990).
	PubMed ID	2253883

6	Authors	Kawata Y., Sakiyama F., Hayashi F., Kyogoku Y.
	Title	Identification of two essential histidine residues of ribonuclease T2 from Aspergillus oryzae.
	Source	Eur. J. Biochem. 187:255-262(1990).
	PubMed ID	2298207

7	Authors	Kurihara H., Mitsui Y., Ohgi K., Irie M., Mizuno H., Nakamura K.T.
	Title	Crystal and molecular structure of RNase Rh, a new class of microbial ribonuclease from Rhizopus niveus.
	Source	FEBS Lett. 306:189-192(1992).
	PubMed ID	1633875

8	Authors	Bairoch A.
	Source	Unpublished observations (1993).

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