ID RELE_ECOLI Reviewed; 95 AA. AC P0C077; P07008; DT 01-APR-1988, integrated into UniProtKB/Swiss-Prot. DT 01-APR-1988, sequence version 1. DT 24-JAN-2024, entry version 136. DE RecName: Full=mRNA interferase toxin RelE; DE EC=3.1.-.-; DE AltName: Full=Endoribonuclease RelE; DE AltName: Full=Toxin RelE; GN Name=relE; OrderedLocusNames=b1563, JW1555; OS Escherichia coli (strain K12). OC Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales; OC Enterobacteriaceae; Escherichia. OX NCBI_TaxID=83333; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RC STRAIN=K12 / CS520; RX PubMed=2990907; DOI=10.1002/j.1460-2075.1985.tb03739.x; RA Bech F.W., Joergensen S.T., Diderichsen B., Karlstroem O.H.; RT "Sequence of the relB transcription unit from Escherichia coli and RT identification of the relB gene."; RL EMBO J. 4:1059-1066(1985). RN [2] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911; RX PubMed=9097039; DOI=10.1093/dnares/3.6.363; RA Aiba H., Baba T., Fujita K., Hayashi K., Inada T., Isono K., Itoh T., RA Kasai H., Kashimoto K., Kimura S., Kitakawa M., Kitagawa M., Makino K., RA Miki T., Mizobuchi K., Mori H., Mori T., Motomura K., Nakade S., RA Nakamura Y., Nashimoto H., Nishio Y., Oshima T., Saito N., Sampei G., RA Seki Y., Sivasundaram S., Tagami H., Takeda J., Takemoto K., Takeuchi Y., RA Wada C., Yamamoto Y., Horiuchi T.; RT "A 570-kb DNA sequence of the Escherichia coli K-12 genome corresponding to RT the 28.0-40.1 min region on the linkage map."; RL DNA Res. 3:363-377(1996). RN [3] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / MG1655 / ATCC 47076; RX PubMed=9278503; DOI=10.1126/science.277.5331.1453; RA Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., RA Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., RA Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., RA Shao Y.; RT "The complete genome sequence of Escherichia coli K-12."; RL Science 277:1453-1462(1997). RN [4] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911; RX PubMed=16738553; DOI=10.1038/msb4100049; RA Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., RA Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T.; RT "Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 RT and W3110."; RL Mol. Syst. Biol. 2:E1-E5(2006). RN [5] RP FUNCTION AS A TOXIN, FUNCTION AS A TRANSCRIPTIONAL COREPRESSOR, AND RP INDUCTION. RX PubMed=9767574; DOI=10.1046/j.1365-2958.1998.00993.x; RA Gotfredsen M., Gerdes K.; RT "The Escherichia coli relBE genes belong to a new toxin-antitoxin gene RT family."; RL Mol. Microbiol. 29:1065-1076(1998). RN [6] RP FUNCTION, SUBUNIT, AND RIBOSOME-BINDING. RX PubMed=11274135; DOI=10.1128/jb.183.8.2700-2703.2001; RA Galvani C., Terry J., Ishiguro E.E.; RT "Purification of the RelB and RelE proteins of Escherichia coli: RelE binds RT to RelB and to ribosomes."; RL J. Bacteriol. 183:2700-2703(2001). RN [7] RP FUNCTION AS A TRANSLATION INHIBITOR, INDUCTION, AND DISRUPTION PHENOTYPE. RX PubMed=11717402; DOI=10.1073/pnas.251327898; RA Christensen S.K., Mikkelsen M., Pedersen K., Gerdes K.; RT "RelE, a global inhibitor of translation, is activated during nutritional RT stress."; RL Proc. Natl. Acad. Sci. U.S.A. 98:14328-14333(2001). RN [8] RP FUNCTION AS A TOXIN, AND MUTAGENESIS OF ARG-81 AND 90-ALA--LEU-95. RC STRAIN=K12; RX PubMed=12123459; DOI=10.1046/j.1365-2958.2002.03027.x; RA Pedersen K., Christensen S.K., Gerdes K.; RT "Rapid induction and reversal of a bacteriostatic condition by controlled RT expression of toxins and antitoxins."; RL Mol. Microbiol. 45:501-510(2002). RN [9] RP FUNCTION AS AN ENDORIBONUCLEASE ON THE RIBOSOME, AND SUBSTRATE SPECIFICITY. RX PubMed=12526800; DOI=10.1016/s0092-8674(02)01248-5; RA Pedersen K., Zavialov A.V., Pavlov M.Y., Elf J., Gerdes K., Ehrenberg M.; RT "The bacterial toxin RelE displays codon-specific cleavage of mRNAs in the RT ribosomal A site."; RL Cell 112:131-140(2003). RN [10] RP RELATION WITH PERSISTERS. RX PubMed=15576765; DOI=10.1128/jb.186.24.8172-8180.2004; RA Keren I., Shah D., Spoering A., Kaldalu N., Lewis K.; RT "Specialized persister cells and the mechanism of multidrug tolerance in RT Escherichia coli."; RL J. Bacteriol. 186:8172-8180(2004). RN [11] RP FUNCTION IN CELL DEATH, DISRUPTION PHENOTYPE, AND ANTIBIOTIC RESISTANCE. RC STRAIN=K12 / MC4100 / ATCC 35695 / DSM 6574; RX PubMed=19707553; DOI=10.1371/journal.pone.0006785; RA Kolodkin-Gal I., Verdiger R., Shlosberg-Fedida A., Engelberg-Kulka H.; RT "A differential effect of E. coli toxin-antitoxin systems on cell death in RT liquid media and biofilm formation."; RL PLoS ONE 4:E6785-E6785(2009). RN [12] RP FUNCTION, SUBUNIT, AND INDUCTION. RX PubMed=18501926; DOI=10.1016/j.jmb.2008.04.039; RA Li G.Y., Zhang Y., Inouye M., Ikura M.; RT "Structural mechanism of transcriptional autorepression of the Escherichia RT coli RelB/RelE antitoxin/toxin module."; RL J. Mol. Biol. 380:107-119(2008). RN [13] RP FUNCTION, SUBUNIT, AND INDUCTION. RC STRAIN=K12; RX PubMed=18532983; DOI=10.1111/j.1365-2958.2008.06313.x; RA Overgaard M., Borch J., Joergensen M.G., Gerdes K.; RT "Messenger RNA interferase RelE controls relBE transcription by conditional RT cooperativity."; RL Mol. Microbiol. 69:841-857(2008). RN [14] RP FUNCTION, SUBUNIT, AND INDUCTION. RC STRAIN=K12; RX PubMed=19747491; DOI=10.1016/j.jmb.2009.09.006; RA Overgaard M., Borch J., Gerdes K.; RT "RelB and RelE of Escherichia coli form a tight complex that represses RT transcription via the ribbon-helix-helix motif in RelB."; RL J. Mol. Biol. 394:183-196(2009). RN [15] RP FUNCTION, AND DISRUPTION PHENOTYPE. RC STRAIN=K12 / MC4100 / ATCC 35695 / DSM 6574; RX PubMed=20005847; DOI=10.1016/j.molcel.2009.11.024; RA Davies B.W., Kohanski M.A., Simmons L.A., Winkler J.A., Collins J.J., RA Walker G.C.; RT "Hydroxyurea induces hydroxyl radical-mediated cell death in Escherichia RT coli."; RL Mol. Cell 36:845-860(2009). RN [16] RP FUNCTION, AND SUBSTRATE SPECIFICITY. RC STRAIN=K12 / BW25113; RX PubMed=21324908; DOI=10.1074/jbc.m110.108969; RA Hurley J.M., Cruz J.W., Ouyang M., Woychik N.A.; RT "Bacterial toxin RelE mediates frequent codon-independent mRNA cleavage RT from the 5' end of coding regions in vivo."; RL J. Biol. Chem. 286:14770-14778(2011). RN [17] RP RETRACTED PAPER. RC STRAIN=K12 / MG1655 / ATCC 47076; RX PubMed=21788497; DOI=10.1073/pnas.1100186108; RA Maisonneuve E., Shakespeare L.J., Joergensen M.G., Gerdes K.; RT "Bacterial persistence by RNA endonucleases."; RL Proc. Natl. Acad. Sci. U.S.A. 108:13206-13211(2011). RN [18] RP RETRACTION NOTICE OF PUBMED:21788497. RX PubMed=29531044; DOI=10.1073/pnas.1803278115; RA Maisonneuve E., Shakespeare L.J., Joergensen M.G., Gerdes K.; RL Proc. Natl. Acad. Sci. U.S.A. 115:E2901-E2901(2018). RN [19] RP FUNCTION IN DORMANCY, AND ANTIBIOTIC RESISTANCE. RC STRAIN=K12 / MG1655 / ATCC 47076; RX PubMed=22210768; DOI=10.1128/jb.06628-11; RA Tashiro Y., Kawata K., Taniuchi A., Kakinuma K., May T., Okabe S.; RT "RelE-mediated dormancy is enhanced at high cell density in Escherichia RT coli."; RL J. Bacteriol. 194:1169-1176(2012). RN [20] RP FUNCTION, AND INDUCTION BY OTHER TA SYSTEMS. RC STRAIN=K12 / BW25113; RX PubMed=23432955; DOI=10.1186/1471-2180-13-45; RA Kasari V., Mets T., Tenson T., Kaldalu N.; RT "Transcriptional cross-activation between toxin-antitoxin systems of RT Escherichia coli."; RL BMC Microbiol. 13:45-45(2013). RN [21] RP FUNCTION, PROBABLE ACTIVE SITE, AND MUTAGENESIS OF LYS-52; LYS-54; ARG-61; RP ARG-81 AND TYR-87. RC STRAIN=K12 / MG1655 / ATCC 47076; RX PubMed=24251350; DOI=10.1021/bi401325c; RA Griffin M.A., Davis J.H., Strobel S.A.; RT "Bacterial toxin RelE: a highly efficient ribonuclease with exquisite RT substrate specificity using atypical catalytic residues."; RL Biochemistry 52:8633-8642(2013). RN [22] RP REVIEW. RX PubMed=19215780; DOI=10.1016/s0079-6603(08)00812-x; RA Yamaguchi Y., Inouye M.; RT "mRNA interferases, sequence-specific endoribonucleases from the toxin- RT antitoxin systems."; RL Prog. Mol. Biol. Transl. Sci. 85:467-500(2009). RN [23] RP X-RAY CRYSTALLOGRAPHY (2.5 ANGSTROMS) IN ISOLATION AND BOUND TO RIBOSOMES RP BEFORE AND AFTER MRNA CLEAVAGE, FUNCTION, RIBOSOME-BINDING, RRNA-BINDING, RP MECHANISM OF RNA CLEAVAGE, AND MUTAGENESIS OF ARG-61; ARG-81 AND TYR-87. RX PubMed=20005802; DOI=10.1016/j.cell.2009.11.015; RA Neubauer C., Gao Y.G., Andersen K.R., Dunham C.M., Kelley A.C., RA Hentschel J., Gerdes K., Ramakrishnan V., Brodersen D.E.; RT "The structural basis for mRNA recognition and cleavage by the ribosome- RT dependent endonuclease RelE."; RL Cell 139:1084-1095(2009). RN [24] RP STRUCTURE BY NMR OF MUTANT 81-ARG--ARG-83 IN COMPLEX WITH RELB FRAGMENT, RP AND SUBUNIT. RX PubMed=19297318; DOI=10.1074/jbc.m809656200; RA Li G.Y., Zhang Y., Inouye M., Ikura M.; RT "Inhibitory mechanism of Escherichia coli RelE-RelB toxin-antitoxin module RT involves a helix displacement near an mRNA interferase active site."; RL J. Biol. Chem. 284:14628-14636(2009). RN [25] RP X-RAY CRYSTALLOGRAPHY (1.80 ANGSTROMS) AND X-RAY CRYSTALLOGRAPHY (2.75 RP ANGSTROMS) IN COMPLEX WITH RELE, FUNCTION, SUBUNIT, AND INDUCTION. RX PubMed=22981948; DOI=10.1016/j.str.2012.08.017; RA Boggild A., Sofos N., Andersen K.R., Feddersen A., Easter A.D., RA Passmore L.A., Brodersen D.E.; RT "The crystal structure of the intact E. coli RelBE toxin-antitoxin complex RT provides the structural basis for conditional cooperativity."; RL Structure 20:1641-1648(2012). CC -!- FUNCTION: Toxic component of a type II toxin-antitoxin (TA) system CC (PubMed:9767574). A sequence-specific, ribosome-dependent mRNA CC endoribonuclease that inhibits translation during amino acid starvation CC (the stringent response). In vitro acts by cleaving mRNA with high CC codon specificity in the ribosomal A site between positions 2 and 3. CC The stop codon UAG is cleaved at a fast rate while UAA and UGA are CC cleaved with intermediate and slow rates. In vitro mRNA cleavage can CC also occur in the ribosomal E site after peptide release from peptidyl- CC tRNA in the P site as well as on free 30S subunits (PubMed:12526800). CC In vivo cuts frequently in the first 100 codons, most frequently after CC the second and third base and rarely near the stop codon CC (PubMed:21324908). Overexpression of RelE results in the inhibition of CC bacterial growth and a sharp decrease in colony-forming ability which CC is neutralized by the labile cognate antitoxin RelB. Overexpression CC also sharply increases persisters (cells that neither grow nor die in CC the presence of bactericidal agents and are largely responsible for CC high levels of biofilm tolerance to antimicrobials) (PubMed:15576765). CC Plays a role in dormancy when expressed in high-density cells in the CC absence of antitoxin RelB; amino acid starvation and an unidentified CC extracellular factor promote dormancy, while expression of antitoxin CC RelB restores cell culturability (PubMed:22210768). Acts with RelB as a CC corepressor of relBE transcription, considerably increasing the CC repression of RelB alone. 2 RelB dimers bind to 2 operator sequences; CC DNA-binding and repression is stronger when complexed with CC toxin/corepressor RelE by conditional cooperativity (PubMed:9767574, CC PubMed:19747491, PubMed:18501926, PubMed:22981948). CC {ECO:0000269|PubMed:11274135, ECO:0000269|PubMed:11717402, CC ECO:0000269|PubMed:12123459, ECO:0000269|PubMed:12526800, CC ECO:0000269|PubMed:15576765, ECO:0000269|PubMed:18501926, CC ECO:0000269|PubMed:18532983, ECO:0000269|PubMed:19747491, CC ECO:0000269|PubMed:20005802, ECO:0000269|PubMed:21324908, CC ECO:0000269|PubMed:22210768, ECO:0000269|PubMed:22981948, CC ECO:0000269|PubMed:24251350, ECO:0000269|PubMed:9767574}. CC -!- FUNCTION: Seems to be a principal mediator of cell death in liquid CC media (PubMed:19707553). Implicated in hydroxy radical-mediated cell CC death induced by hydroxyurea treatment (PubMed:20005847). CC {ECO:0000269|PubMed:19707553, ECO:0000269|PubMed:20005847}. CC -!- FUNCTION: Cross-talk can occur between different TA systems. Ectopic CC expression of this toxin induces transcription of 7 tested TA systems CC (dinJ/yafQ, hicAB, mazEF, mqsRA, prlF(sohA)/yhaV, relBEF and yefM/yoeB) CC with specific cleavage of the relBEF mRNA produced immediately upstream CC and within the relB coding sequence. The cleaved mRNA can be translated CC into RelE, leading to a positive feedback cycle of RelE expression. The CC relBEF operon is required for transcription of the mazEF TA system CC operon during amino acid starvation. {ECO:0000269|PubMed:23432955}. CC -!- SUBUNIT: Forms an RelB(2)-RelE(2) heterotetramer (PubMed:18501926, CC PubMed:22981948). Also forms an RelB(2)-RelE heterotrimer CC (PubMed:18532983, PubMed:19747491). The RelB(2)-RelE complex is CC probably the one that binds DNA and represses transcription, possibly CC as 2 heterotrimers, 1 bound to each of 2 operators (PubMed:22981948, CC PubMed:19747491). RelE occupies the A site of the 70S ribosome, making CC extensive contacts with the 16S rRNA. Its presence blocks access of CC tRNAs and translation factors. RelB bound to RelE prevents RelE from CC entering the ribosomal A site and thus inhibits its endonuclease CC activity (PubMed:19297318). {ECO:0000269|PubMed:11274135, CC ECO:0000269|PubMed:18501926, ECO:0000269|PubMed:18532983, CC ECO:0000269|PubMed:19297318, ECO:0000269|PubMed:19747491, CC ECO:0000269|PubMed:22981948}. CC -!- INTERACTION: CC P0C077; P0C079: relB; NbExp=3; IntAct=EBI-549378, EBI-1124503; CC -!- INDUCTION: By amino acid starvation, by glucose starvation and by CC chloramphenicol; induction is independent of ppGpp. Autorepressed by CC RelB, RelE acts as a corepressor (PubMed:9767574, PubMed:19747491, CC PubMed:18501926, PubMed:22981948). Member of the relBEF operon CC (PubMed:2990907). Operon induced by ectopic expression of toxins HicA, CC HipA, MazF, MqsR and itself, but not by YafQ (PubMed:23432955). CC {ECO:0000269|PubMed:11717402, ECO:0000269|PubMed:18501926, CC ECO:0000269|PubMed:18532983, ECO:0000269|PubMed:19747491, CC ECO:0000269|PubMed:22981948, ECO:0000269|PubMed:23432955, CC ECO:0000269|PubMed:2990907, ECO:0000269|PubMed:9767574}. CC -!- DISRUPTION PHENOTYPE: Cells missing relBE have a higher steady-state CC level of translation during amino acid starvation than wild-type cells. CC They survive antibiotic treatment in log phase better than wild-type CC cells. Cells missing mazE-mazF survive hydroxyurea treatment better CC than wild-type; further disruption of relE-relB and tonB yields even CC better survival (PubMed:20005847). {ECO:0000269|PubMed:11717402, CC ECO:0000269|PubMed:19707553, ECO:0000269|PubMed:20005847}. CC -!- MISCELLANEOUS: There are estimated to be 550-1100 RelB and 50-100 RelE CC molecules in rapidly growing cells of MG1655; as they have quite high CC affinity for each other (dissociation constant of 0.33 nM) there is CC probably less than 1 free RelE molecule per cell. The RelB(2)-RelE CC complex has a half-life of over 70 minutes. CC {ECO:0000269|PubMed:19747491}. CC -!- SIMILARITY: Belongs to the RelE toxin family. {ECO:0000305}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; X02405; CAA26251.1; -; Genomic_DNA. DR EMBL; U00096; AAC74636.1; -; Genomic_DNA. DR EMBL; AP009048; BAA15262.1; -; Genomic_DNA. DR PIR; B22830; QQECR1. DR RefSeq; NP_416081.1; NC_000913.3. DR RefSeq; WP_000323025.1; NZ_SSUV01000001.1. DR PDB; 2KC8; NMR; -; A=1-95. DR PDB; 2KC9; NMR; -; A=1-95. DR PDB; 4FXE; X-ray; 2.75 A; D/E/F=1-95. DR PDB; 4FXH; X-ray; 2.40 A; A/B=1-95. DR PDB; 4FXI; X-ray; 1.80 A; A/B/C=1-95. DR PDB; 4V7J; X-ray; 3.30 A; Ay/By=1-95. DR PDB; 4V7K; X-ray; 3.60 A; Ay/By=1-95. DR PDBsum; 2KC8; -. DR PDBsum; 2KC9; -. DR PDBsum; 4FXE; -. DR PDBsum; 4FXH; -. DR PDBsum; 4FXI; -. DR PDBsum; 4V7J; -. DR PDBsum; 4V7K; -. DR AlphaFoldDB; P0C077; -. DR BMRB; P0C077; -. DR SMR; P0C077; -. DR BioGRID; 4260243; 249. DR ComplexPortal; CPX-1081; RelBE toxin-antitoxin complex. DR DIP; DIP-35978N; -. DR IntAct; P0C077; 12. DR STRING; 511145.b1563; -. DR jPOST; P0C077; -. DR PaxDb; 511145-b1563; -. DR EnsemblBacteria; AAC74636; AAC74636; b1563. DR GeneID; 72533945; -. DR GeneID; 947549; -. DR KEGG; ecj:JW1555; -. DR KEGG; eco:b1563; -. DR PATRIC; fig|1411691.4.peg.699; -. DR EchoBASE; EB1121; -. DR eggNOG; COG2026; Bacteria. DR HOGENOM; CLU_155761_0_1_6; -. DR InParanoid; P0C077; -. DR OMA; GHADRYK; -. DR OrthoDB; 9801234at2; -. DR PhylomeDB; P0C077; -. DR BioCyc; EcoCyc:EG11131-MONOMER; -. DR BioCyc; MetaCyc:EG11131-MONOMER; -. DR EvolutionaryTrace; P0C077; -. DR PRO; PR:P0C077; -. DR Proteomes; UP000000318; Chromosome. DR Proteomes; UP000000625; Chromosome. DR CollecTF; EXPREG_00000890; -. DR GO; GO:0032993; C:protein-DNA complex; IMP:CollecTF. DR GO; GO:0110001; C:toxin-antitoxin complex; IPI:ComplexPortal. DR GO; GO:0001217; F:DNA-binding transcription repressor activity; IMP:CollecTF. DR GO; GO:0043022; F:ribosome binding; IDA:EcoCyc. DR GO; GO:0004521; F:RNA endonuclease activity; IDA:EcoCyc. DR GO; GO:0019843; F:rRNA binding; IEA:UniProtKB-KW. DR GO; GO:0097351; F:toxin sequestering activity; EXP:DisProt. DR GO; GO:0000976; F:transcription cis-regulatory region binding; IMP:CollecTF. DR GO; GO:0034198; P:cellular response to amino acid starvation; IEP:EcoCyc. DR GO; GO:0006402; P:mRNA catabolic process; IDA:EcoCyc. DR GO; GO:0017148; P:negative regulation of translation; IDA:EcoCyc. DR GO; GO:0006355; P:regulation of DNA-templated transcription; NAS:ComplexPortal. DR GO; GO:0040008; P:regulation of growth; NAS:ComplexPortal. DR GO; GO:0046677; P:response to antibiotic; IMP:EcoCyc. DR GO; GO:0044010; P:single-species biofilm formation; IDA:ComplexPortal. DR DisProt; DP01881; -. DR Gene3D; 3.30.2310.20; RelE-like; 1. DR InterPro; IPR007712; RelE/ParE_toxin. DR InterPro; IPR035093; RelE/ParE_toxin_dom_sf. DR NCBIfam; TIGR02385; RelE_StbE; 1. DR PANTHER; PTHR35601:SF2; MRNA INTERFERASE TOXIN RELE; 1. DR PANTHER; PTHR35601; TOXIN RELE; 1. DR Pfam; PF05016; ParE_toxin; 1. DR SUPFAM; SSF143011; RelE-like; 1. PE 1: Evidence at protein level; KW 3D-structure; Antibiotic resistance; Endonuclease; Hydrolase; Nuclease; KW Reference proteome; Repressor; RNA-binding; rRNA-binding; Stress response; KW Toxin-antitoxin system; Transcription; Transcription regulation. FT CHAIN 1..95 FT /note="mRNA interferase toxin RelE" FT /id="PRO_0000097245" FT ACT_SITE 52 FT /note="Proton acceptor" FT /evidence="ECO:0000305|PubMed:24251350" FT ACT_SITE 81 FT /note="Proton donor" FT /evidence="ECO:0000305|PubMed:24251350" FT SITE 54 FT /note="Transition state stabilizer" FT /evidence="ECO:0000305|PubMed:24251350" FT SITE 61 FT /note="Transition state stabilizer" FT /evidence="ECO:0000305|PubMed:24251350" FT MUTAGEN 52 FT /note="K->A: Reduces mRNA cleavage rate constant 2100-fold. FT Reduces mRNA cleavage rate constant 1000000-fold; when FT associated with F-87." FT /evidence="ECO:0000269|PubMed:24251350" FT MUTAGEN 54 FT /note="K->A: Reduces mRNA cleavage rate constant FT 2700-fold." FT /evidence="ECO:0000269|PubMed:24251350" FT MUTAGEN 61 FT /note="R->A: Reduces mRNA cleavage rate constant FT 2700000-fold." FT /evidence="ECO:0000269|PubMed:20005802, FT ECO:0000269|PubMed:24251350" FT MUTAGEN 81..83 FT /note="RER->AEA: Significant reduction in endonuclease FT activity, still binds RelB." FT /evidence="ECO:0000269|PubMed:19297318" FT MUTAGEN 81 FT /note="R->A: Reduces mRNA cleavage rate constant FT 60000-fold, significantly less translation inhibition which FT is countered by RelB. Almost complete loss of mRNA FT cleavage; when associated with F-87." FT /evidence="ECO:0000269|PubMed:12123459, FT ECO:0000269|PubMed:20005802, ECO:0000269|PubMed:24251350" FT MUTAGEN 87 FT /note="Y->A: Reduces mRNA cleavage rate constant FT 180000-fold." FT /evidence="ECO:0000269|PubMed:20005802, FT ECO:0000269|PubMed:24251350" FT MUTAGEN 87 FT /note="Y->F: Reduces mRNA cleavage rate constant 130-fold. FT Almost complete loss of mRNA cleavage; when associated with FT A-81 (Ref.20). Reduces mRNA cleavage rate constant FT 1000000-fold; when associated with A-52 (Ref.18)." FT /evidence="ECO:0000269|PubMed:20005802, FT ECO:0000269|PubMed:24251350" FT MUTAGEN 90..95 FT /note="AVKRIL->VTVTVT: Does not inhibit translation." FT /evidence="ECO:0000269|PubMed:12123459" FT STRAND 4..7 FT /evidence="ECO:0007829|PDB:4FXI" FT HELIX 9..17 FT /evidence="ECO:0007829|PDB:4FXI" FT HELIX 20..35 FT /evidence="ECO:0007829|PDB:4FXI" FT HELIX 40..42 FT /evidence="ECO:0007829|PDB:4FXI" FT STRAND 45..47 FT /evidence="ECO:0007829|PDB:4FXI" FT STRAND 50..54 FT /evidence="ECO:0007829|PDB:4FXI" FT TURN 56..59 FT /evidence="ECO:0007829|PDB:4FXH" FT STRAND 60..67 FT /evidence="ECO:0007829|PDB:4FXI" FT HELIX 68..70 FT /evidence="ECO:0007829|PDB:4FXI" FT STRAND 72..80 FT /evidence="ECO:0007829|PDB:4FXI" FT HELIX 82..84 FT /evidence="ECO:0007829|PDB:4FXI" FT HELIX 85..94 FT /evidence="ECO:0007829|PDB:4FXI" SQ SEQUENCE 95 AA; 11225 MW; F516B2E7A437CCEC CRC64; MAYFLDFDER ALKEWRKLGS TVREQLKKKL VEVLESPRIE ANKLRGMPDC YKIKLRSSGY RLVYQVIDEK VVVFVISVGK RERSEVYSEA VKRIL //