HACB_METMA
ID HACB_METMA Reviewed; 169 AA.
AC Q8PZ49;
DT 19-SEP-2002, integrated into UniProtKB/Swiss-Prot.
DT 19-SEP-2002, sequence version 1.
DT 25-MAY-2022, entry version 127.
DE RecName: Full=Methanogen homoaconitase small subunit;
DE Short=HACN;
DE EC=4.2.1.114 {ECO:0000250|UniProtKB:Q58667};
DE AltName: Full=Homoaconitate hydratase;
GN Name=hacB; OrderedLocusNames=MM_0645;
OS Methanosarcina mazei (strain ATCC BAA-159 / DSM 3647 / Goe1 / Go1 / JCM
OS 11833 / OCM 88) (Methanosarcina frisia).
OC Archaea; Euryarchaeota; Stenosarchaea group; Methanomicrobia;
OC Methanosarcinales; Methanosarcinaceae; Methanosarcina.
OX NCBI_TaxID=192952;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=ATCC BAA-159 / DSM 3647 / Goe1 / Go1 / JCM 11833 / OCM 88;
RX PubMed=12125824;
RA Deppenmeier U., Johann A., Hartsch T., Merkl R., Schmitz R.A.,
RA Martinez-Arias R., Henne A., Wiezer A., Baeumer S., Jacobi C.,
RA Brueggemann H., Lienard T., Christmann A., Boemecke M., Steckel S.,
RA Bhattacharyya A., Lykidis A., Overbeek R., Klenk H.-P., Gunsalus R.P.,
RA Fritz H.-J., Gottschalk G.;
RT "The genome of Methanosarcina mazei: evidence for lateral gene transfer
RT between Bacteria and Archaea.";
RL J. Mol. Microbiol. Biotechnol. 4:453-461(2002).
CC -!- FUNCTION: Component of a hydro-lyase with broad substrate specificity
CC for cis-unsaturated tricarboxylic acids. Catalyzes both the reversible
CC dehydration of (R)-homocitrate ((R)-2-hydroxybutane-1,2,4-
CC tricarboxylate) to produce cis-homoaconitate ((Z)-but-1-ene-1,2,4-
CC tricarboxylate), and its hydration to homoisocitrate ((1R,2S)-1-
CC hydroxybutane-1,2,4-tricarboxylate). Is also able to hydrate the
CC analogous longer chain substrates cis-homo(2)-aconitate, cis-homo(3)-
CC aconitate. These reactions are part of the biosynthesis pathway of
CC coenzyme B. {ECO:0000250|UniProtKB:Q58667}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(2R)-homocitrate = (2R,3S)-homoisocitrate;
CC Xref=Rhea:RHEA:32303, ChEBI:CHEBI:15404, ChEBI:CHEBI:58884;
CC EC=4.2.1.114; Evidence={ECO:0000250|UniProtKB:Q58667};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:32304;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(2R)-homocitrate = cis-homoaconitate + H2O;
CC Xref=Rhea:RHEA:26101, ChEBI:CHEBI:15377, ChEBI:CHEBI:58174,
CC ChEBI:CHEBI:58884; Evidence={ECO:0000250|UniProtKB:Q58667};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:26102;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(2R,3S)-homoisocitrate = cis-homoaconitate + H2O;
CC Xref=Rhea:RHEA:15485, ChEBI:CHEBI:15377, ChEBI:CHEBI:15404,
CC ChEBI:CHEBI:58174; Evidence={ECO:0000250|UniProtKB:Q58667};
CC PhysiologicalDirection=right-to-left; Xref=Rhea:RHEA:15487;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=cis-(homo)2aconitate + H2O = (2R,3S)-iso(homo)2citrate;
CC Xref=Rhea:RHEA:68416, ChEBI:CHEBI:15377, ChEBI:CHEBI:72710,
CC ChEBI:CHEBI:72722; EC=4.2.1.114;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:68417;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=cis-(homo)3aconitate + H2O = (2R,3S)-iso(homo)3citrate;
CC Xref=Rhea:RHEA:68420, ChEBI:CHEBI:15377, ChEBI:CHEBI:72712,
CC ChEBI:CHEBI:177881; EC=4.2.1.114;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:68421;
CC Evidence={ECO:0000250|UniProtKB:Q58667};
CC -!- PATHWAY: Organic acid metabolism; 2-oxosuberate biosynthesis.
CC {ECO:0000250|UniProtKB:Q58667}.
CC -!- SUBUNIT: Heterotetramer of 2 HacA and 2 HacB proteins.
CC {ECO:0000250|UniProtKB:Q58667}.
CC -!- SIMILARITY: Belongs to the LeuD family. LeuD type 2 subfamily.
CC {ECO:0000305}.
CC -!- CAUTION: Functional assignment as methanogen HACN has been made based
CC on the presence of the YLRT motif involved in substrate specificity as
CC discussed in PubMed:20170198. {ECO:0000305}.
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DR EMBL; AE008384; AAM30341.1; -; Genomic_DNA.
DR AlphaFoldDB; Q8PZ49; -.
DR SMR; Q8PZ49; -.
DR STRING; 192952.MM_0645; -.
DR EnsemblBacteria; AAM30341; AAM30341; MM_0645.
DR KEGG; mma:MM_0645; -.
DR PATRIC; fig|192952.21.peg.763; -.
DR eggNOG; arCOG02230; Archaea.
DR HOGENOM; CLU_081378_1_1_2; -.
DR OMA; GLPIIEC; -.
DR UniPathway; UPA00919; -.
DR Proteomes; UP000000595; Chromosome.
DR GO; GO:0004409; F:homoaconitate hydratase activity; IEA:UniProtKB-UniRule.
DR GO; GO:0019298; P:coenzyme B biosynthetic process; IEA:UniProtKB-UniRule.
DR CDD; cd01577; IPMI_Swivel; 1.
DR Gene3D; 3.20.19.10; -; 1.
DR HAMAP; MF_01032; LeuD_type2; 1.
DR InterPro; IPR015928; Aconitase/3IPM_dehydase_swvl.
DR InterPro; IPR000573; AconitaseA/IPMdHydase_ssu_swvl.
DR InterPro; IPR033940; IPMI_Swivel.
DR InterPro; IPR011827; LeuD_type2/HacB/DmdB.
DR Pfam; PF00694; Aconitase_C; 1.
DR TIGRFAMs; TIGR02087; LEUD_arch; 1.
PE 3: Inferred from homology;
KW Lyase; Reference proteome.
FT CHAIN 1..169
FT /note="Methanogen homoaconitase small subunit"
FT /id="PRO_0000141940"
FT MOTIF 27..30
FT /note="YLRT"
FT SITE 29
FT /note="Critical for substrate specificity"
FT /evidence="ECO:0000250"
SQ SEQUENCE 169 AA; 18489 MW; 3E1AFAEE5EDD0CBE CRC64;
MMENPIKGRV WKFGNDIDTD VIIPGKYLRT KDMQVFAAHA MEGIDPGFSK KAKPGDIIVA
GDNFGCGSSR EQAPLALKHA GIACIVAKSF ARIFFRNAIN IGLPLMEADI ECEEGDQIEV
DLLKGEVKVS GKGVFRGNKL PDFLLDMLTD GGLVAHRKKV RDQEKEESA
