HEPT_APHF2
ID HEPT_APHF2 Reviewed; 147 AA.
AC A0A0B0QJR1;
DT 07-APR-2021, integrated into UniProtKB/Swiss-Prot.
DT 07-APR-2021, sequence version 2.
DT 25-MAY-2022, entry version 25.
DE RecName: Full=tRNA nuclease HepT {ECO:0000303|PubMed:33290744};
DE EC=3.1.27.- {ECO:0000269|PubMed:33290744};
DE AltName: Full=Toxin HEPN {ECO:0000303|PubMed:33290744};
DE AltName: Full=tRNA nuclease HEPN {ECO:0000303|PubMed:33290744};
GN Name=hepT {ECO:0000303|PubMed:33290744};
GN Synonyms=hepn {ECO:0000303|PubMed:33290744}; ORFNames=OA07_26455;
OS Aphanizomenon flos-aquae (strain 2012/KM1/D3).
OC Bacteria; Cyanobacteria; Nostocales; Aphanizomenonaceae; Aphanizomenon.
OX NCBI_TaxID=1532906;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=2012/KM1/D3;
RX PubMed=25593252; DOI=10.1128/genomea.01392-14;
RA Sulcius S., Alzbutas G., Kvederaviciute K., Koreiviene J., Zakrys L.,
RA Lubys A., Paskauskas R.;
RT "Draft Genome Sequence of the Cyanobacterium Aphanizomenon flos-aquae
RT Strain 2012/KM1/D3, Isolated from the Curonian Lagoon (Baltic Sea).";
RL Genome Announc. 3:0-0(2015).
RN [2] {ECO:0007744|PDB:7AE2, ECO:0007744|PDB:7AE6, ECO:0007744|PDB:7AE8, ECO:0007744|PDB:7AE9}
RP X-RAY CRYSTALLOGRAPHY (1.65 ANGSTROMS) ALONE AND IN COMPLEX WITH MNTA,
RP FUNCTION AS A TOXIN, SUBUNIT, POSSIBLE ACTIVE SITE, DI-AMPYLATION AT
RP TYR-109, MUTAGENESIS OF ARG-12; ARG-46; 102-ARG--TYR-109; ARG-102 AND
RP TYR-109, AND SEQUENCE REVISION TO N-TERMINUS.
RC STRAIN=2012/KM1/D3;
RX PubMed=33290744; DOI=10.1016/j.molcel.2020.11.034;
RA Songailiene I., Juozapaitis J., Tamulaitiene G., Ruksenaite A., Sulcius S.,
RA Sasnauskas G., Venclovas C., Siksnys V.;
RT "HEPN-MNT Toxin-Antitoxin System: The HEPN Ribonuclease Is Neutralized by
RT OligoAMPylation.";
RL Mol. Cell 0:0-0(2020).
CC -!- FUNCTION: Toxic component of a type VII toxin-antitoxin (TA) system.
CC Upon cloning in E.coli inhibits cell growth for several hours;
CC eventually cells recover and start growing. Cleaves the last 4
CC nucleotides from the tRNA acceptor stem (shown in vitro with E.coli
CC tRNA-Glu(UUC)); only cleaves intact tRNA. Has no activity on mRNA.
CC Neutralized by coexpression with cognate antitoxin MntA, which is due
CC to di-AMPylation of the RNase. {ECO:0000269|PubMed:33290744}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(tRNA)-3'-end (ribonucleoside 5'-phosphate)-(guanosyl 5'-
CC phosphate)-(cytosyl 5'-phosphate)-(cytosyl 5'-phosphate)-(adenosine
CC 5'-phosphate) + H2O = GpCpCpA + H(+) + tRNA 3'-end (ribonucleotide
CC 3'-phosphate); Xref=Rhea:RHEA:66608, Rhea:RHEA-COMP:17075, Rhea:RHEA-
CC COMP:17076, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:83062,
CC ChEBI:CHEBI:167197, ChEBI:CHEBI:167198;
CC Evidence={ECO:0000269|PubMed:33290744};
CC -!- SUBUNIT: Homodimer. Forms a complex with MntA, probably MntA(1):HepT(2)
CC in vivo; can only be purified when both Arg-102 and Tyr-109 (or His-107
CC and Tyr-109) of this protein have been mutated. The fully di-AMPylated
CC homodimer is not found in a complex with MntA.
CC {ECO:0000269|PubMed:33290744}.
CC -!- PTM: Di-AMPylated by cognate antitoxin MntA on Tyr-109 when both are
CC expressed in E.coli; GMPylation occurs much less often. Leads to an
CC increase of mass of 659 Da. Di-AMPylation moves the catalytic His-107
CC away from the catalytic center, leading to loss of nuclease activity
CC and thus toxicity. Probably one subunit of the dimer is di-AMPylated,
CC the complex dissociates and then reassociates to di-AMPylate the other
CC HepT subunit. {ECO:0000269|PubMed:33290744}.
CC -!- MISCELLANEOUS: Part of a locus that includes subtype I-D CRISPR-Cas
CC genes. {ECO:0000269|PubMed:25593252}.
CC -!- SIMILARITY: Belongs to the HepT RNase toxin family. {ECO:0000305}.
CC -!- SEQUENCE CAUTION:
CC Sequence=KHG38990.1; Type=Erroneous initiation; Note=Truncated N-terminus.; Evidence={ECO:0000269|PubMed:33290744};
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DR EMBL; JSDP01000312; KHG38990.1; ALT_INIT; Genomic_DNA.
DR PDB; 7AE2; X-ray; 2.00 A; A=1-147.
DR PDB; 7AE6; X-ray; 1.65 A; A/B=1-147.
DR PDB; 7AE8; X-ray; 2.00 A; A/B/C/D=1-147.
DR PDB; 7AE9; X-ray; 2.90 A; A/B/C/D=1-147.
DR PDBsum; 7AE2; -.
DR PDBsum; 7AE6; -.
DR PDBsum; 7AE8; -.
DR PDBsum; 7AE9; -.
DR AlphaFoldDB; A0A0B0QJR1; -.
DR SMR; A0A0B0QJR1; -.
DR EnsemblBacteria; KHG38990; KHG38990; OA07_26455.
DR GO; GO:0110001; C:toxin-antitoxin complex; IEA:InterPro.
DR GO; GO:0004519; F:endonuclease activity; IEA:UniProtKB-KW.
DR GO; GO:0000166; F:nucleotide binding; IEA:UniProtKB-KW.
DR GO; GO:0004540; F:ribonuclease activity; IEA:InterPro.
DR Gene3D; 1.20.120.580; -; 1.
DR InterPro; IPR008201; HepT-like.
DR InterPro; IPR037038; HepT-like_sf.
DR Pfam; PF01934; DUF86; 1.
PE 1: Evidence at protein level;
KW 3D-structure; Endonuclease; Hydrolase; Nuclease; Nucleotide-binding;
KW Phosphoprotein; Toxin-antitoxin system.
FT CHAIN 1..147
FT /note="tRNA nuclease HepT"
FT /id="PRO_0000452432"
FT MOTIF 102..109
FT /note="RX(4)HXY motif"
FT /evidence="ECO:0000269|PubMed:33290744"
FT MOTIF 107..113
FT /note="Y-loop"
FT /evidence="ECO:0000269|PubMed:33290744"
FT ACT_SITE 102
FT /evidence="ECO:0000305|PubMed:33290744"
FT ACT_SITE 107
FT /evidence="ECO:0000305|PubMed:33290744"
FT MOD_RES 109
FT /note="O-di-AMP-tyrosine"
FT /evidence="ECO:0000269|PubMed:33290744,
FT ECO:0007744|PDB:7AE6"
FT MUTAGEN 12
FT /note="R->A: Most protein is di-AMPylated, but a small
FT amount is tri-AMPylated."
FT /evidence="ECO:0000269|PubMed:33290744"
FT MUTAGEN 46
FT /note="R->E: No longer dimerizes."
FT /evidence="ECO:0000269|PubMed:33290744"
FT MUTAGEN 102..109
FT /note="RNRLVHEY->ANRLVHEF: Protein is non-toxic and not
FT AMPylated."
FT /evidence="ECO:0000269|PubMed:33290744"
FT MUTAGEN 102
FT /note="R->A: Protein is no longer toxic, does not cleave
FT tRNA, still AMPylated."
FT /evidence="ECO:0000269|PubMed:33290744"
FT MUTAGEN 109
FT /note="Y->F: Protein is not AMPylated, is toxic, cleaves
FT tRNA, not neutralized by MntA."
FT /evidence="ECO:0000269|PubMed:33290744"
FT HELIX 5..23
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 24..26
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 31..35
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 38..66
FT /evidence="ECO:0007829|PDB:7AE6"
FT STRAND 67..69
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 74..83
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 89..95
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 98..105
FT /evidence="ECO:0007829|PDB:7AE6"
FT STRAND 108..110
FT /evidence="ECO:0007829|PDB:7AE6"
FT HELIX 114..147
FT /evidence="ECO:0007829|PDB:7AE6"
SQ SEQUENCE 147 AA; 17110 MW; 7ED5547340C8811C CRC64;
MTNIEPVIIE TRLELIGRYL DHLKKFENIS LDDYLSSFEQ QLITERLLQL ITQAAIDIND
HILSKLKSGK SYTNFEAFIE LGKYQILTPE LAKQIAPSSG LRNRLVHEYD DIDPNQVFMA
ISFALQQYPL YVRQINSYLI TLEEEND
