HACB1_METAC
ID HACB1_METAC Reviewed; 166 AA.
AC Q8TJM9;
DT 19-SEP-2002, integrated into UniProtKB/Swiss-Prot.
DT 01-JUN-2002, sequence version 1.
DT 25-MAY-2022, entry version 110.
DE RecName: Full=Methanogen homoaconitase small subunit 1;
DE Short=HACN 1;
DE EC=4.2.1.114 {ECO:0000250|UniProtKB:Q58667};
DE AltName: Full=Homoaconitate hydratase 1;
GN Name=hacB1; Synonyms=leuD; OrderedLocusNames=MA_3751;
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.
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; AE010299; AAM07104.1; -; Genomic_DNA.
DR AlphaFoldDB; Q8TJM9; -.
DR SMR; Q8TJM9; -.
DR STRING; 188937.MA_3751; -.
DR EnsemblBacteria; AAM07104; AAM07104; MA_3751.
DR KEGG; mac:MA_3751; -.
DR HOGENOM; CLU_081378_1_1_2; -.
DR InParanoid; Q8TJM9; -.
DR OMA; GLPIIEC; -.
DR PhylomeDB; Q8TJM9; -.
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..166
FT /note="Methanogen homoaconitase small subunit 1"
FT /id="PRO_0000141933"
FT MOTIF 27..30
FT /note="YLRT"
FT SITE 29
FT /note="Critical for substrate specificity"
FT /evidence="ECO:0000250"
SQ SEQUENCE 166 AA; 18151 MW; 4BC4ED4738FDE014 CRC64;
MMKNPIIGRV WKFGDDIDTD VIIPGKYLRT KDMQIFAAHA MEGIAPEFTK KAKPGDIIVA
GENFGCGSSR EQAPLAIKHA GIACVVAKSF ARIFFRNAIN VGLPLMEADI ECQEGDEIEV
DLLKGEVRVP GKGVFVGNKL PDFLLDILTD GGLVSHRKKA QNEQKE
