{PDOC00459} {PS00530; RNASE_T2_1} {PS00531; RNASE_T2_2} {BEGIN} ************************************************* * Ribonuclease T2 family histidine active sites * ************************************************* 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. -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. -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]. -Last update: April 2006 / Pattern revised. [ 1] Watanabe H., Naitoh A., Suyama Y., Inokuchi N., Shimada H., Koyama T., Ohgi K., Irie M. "Primary structure of a base non-specific and adenylic acid preferential ribonuclease from Aspergillus saitoi." J. Biochem. 108:303-310(1990). PubMed=2229029 [ 2] Haring V., Gray J.E., McClure B.A., Anderson M.A., Clarke A.E. "Self-incompatibility: a self-recognition system in plants." Science 250:937-941(1990). PubMed=2237440 [ 3] McClure B.A., Haring V., Ebert P.R., Anderson M.A., Simpson R.J., Sakiyama F., Clarke A.E. "Style self-incompatibility gene products of Nicotiana alata are ribonucleases." Nature 342:955-957(1989). PubMed=2594090; DOI=10.1038/342955a02296281 [ 4] Loeffler A., Glund K., Irie M. Eur. J. Biochem. 214:627-633(1993). [ 5] Meador J. III, Kennell D. "Cloning and sequencing the gene encoding Escherichia coli ribonuclease I: exact physical mapping using the genome library." Gene 95:1-7(1990). PubMed=2253883 [ 6] Kawata Y., Sakiyama F., Hayashi F., Kyogoku Y. "Identification of two essential histidine residues of ribonuclease T2 from Aspergillus oryzae." Eur. J. Biochem. 187:255-262(1990). PubMed=2298207 [ 7] Kurihara H., Mitsui Y., Ohgi K., Irie M., Mizuno H., Nakamura K.T. "Crystal and molecular structure of RNase Rh, a new class of microbial ribonuclease from Rhizopus niveus." FEBS Lett. 306:189-192(1992). PubMed=1633875 [ 8] Bairoch A. Unpublished observations (1993). -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}