HACB2_METAC
ID HACB2_METAC Reviewed; 164 AA.
AC Q8TRF7;
DT 19-SEP-2002, integrated into UniProtKB/Swiss-Prot.
DT 01-JUN-2002, sequence version 1.
DT 25-MAY-2022, entry version 115.
DE RecName: Full=Methanogen homoaconitase small subunit 2;
DE Short=HACN 2;
DE EC=4.2.1.114 {ECO:0000250|UniProtKB:Q58667};
DE AltName: Full=Homoaconitate hydratase 2;
GN Name=hacB2; OrderedLocusNames=MA_1223;
OS Methanosarcina acetivorans (strain ATCC 35395 / DSM 2834 / JCM 12185 /
OS C2A).
OC Archaea; Euryarchaeota; Stenosarchaea group; Methanomicrobia;
OC Methanosarcinales; Methanosarcinaceae; Methanosarcina.
OX NCBI_TaxID=188937;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=ATCC 35395 / DSM 2834 / JCM 12185 / C2A;
RX PubMed=11932238; DOI=10.1101/gr.223902;
RA Galagan J.E., Nusbaum C., Roy A., Endrizzi M.G., Macdonald P., FitzHugh W.,
RA Calvo S., Engels R., Smirnov S., Atnoor D., Brown A., Allen N., Naylor J.,
RA Stange-Thomann N., DeArellano K., Johnson R., Linton L., McEwan P.,
RA McKernan K., Talamas J., Tirrell A., Ye W., Zimmer A., Barber R.D.,
RA Cann I., Graham D.E., Grahame D.A., Guss A.M., Hedderich R.,
RA Ingram-Smith C., Kuettner H.C., Krzycki J.A., Leigh J.A., Li W., Liu J.,
RA Mukhopadhyay B., Reeve J.N., Smith K., Springer T.A., Umayam L.A.,
RA White O., White R.H., de Macario E.C., Ferry J.G., Jarrell K.F., Jing H.,
RA Macario A.J.L., Paulsen I.T., Pritchett M., Sowers K.R., Swanson R.V.,
RA Zinder S.H., Lander E., Metcalf W.W., Birren B.;
RT "The genome of Methanosarcina acetivorans reveals extensive metabolic and
RT physiological diversity.";
RL Genome Res. 12:532-542(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. Cannot form a
CC complex with LeuC. {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; AE010299; AAM04642.1; -; Genomic_DNA.
DR RefSeq; WP_011021244.1; NC_003552.1.
DR AlphaFoldDB; Q8TRF7; -.
DR SMR; Q8TRF7; -.
DR STRING; 188937.MA_1223; -.
DR EnsemblBacteria; AAM04642; AAM04642; MA_1223.
DR GeneID; 1473111; -.
DR KEGG; mac:MA_1223; -.
DR HOGENOM; CLU_081378_1_1_2; -.
DR InParanoid; Q8TRF7; -.
DR OMA; DDVNTDY; -.
DR OrthoDB; 86621at2157; -.
DR PhylomeDB; Q8TRF7; -.
DR UniPathway; UPA00919; -.
DR Proteomes; UP000002487; 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..164
FT /note="Methanogen homoaconitase small subunit 2"
FT /id="PRO_0000141935"
FT MOTIF 26..29
FT /note="YLRT"
FT SITE 28
FT /note="Critical for substrate specificity"
FT /evidence="ECO:0000250"
SQ SEQUENCE 164 AA; 17963 MW; 7D46606C68589AC0 CRC64;
MANPIVGRVW KFGDDINTDA IIPGKYLRTR DMQIFGTHAM EGIDPEFTKK AKPGDIIVAG
TNFGCGSSRE QAPLALKHSG IACIVAKSFA RIFFRNAINI GLPLMEADVE CQEGDEIKVD
LFKGEVLVPE KGIFKGNKLP DFLLDILNDG GLVAHRKKVK GEHK
