HACB_THET2
ID HACB_THET2 Reviewed; 163 AA.
AC Q9ZND9;
DT 19-SEP-2002, integrated into UniProtKB/Swiss-Prot.
DT 01-MAY-1999, sequence version 1.
DT 03-AUG-2022, entry version 111.
DE RecName: Full=Homoaconitase small subunit;
DE Short=HACN;
DE EC=4.2.1.36;
DE AltName: Full=Homoaconitate hydratase;
GN Name=hacB; Synonyms=lys4B, lysU; OrderedLocusNames=TT_C1546;
OS Thermus thermophilus (strain ATCC BAA-163 / DSM 7039 / HB27).
OC Bacteria; Deinococcus-Thermus; Deinococci; Thermales; Thermaceae; Thermus.
OX NCBI_TaxID=262724;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=10074061; DOI=10.1128/jb.181.6.1713-1718.1999;
RA Kobashi N., Nishiyama M., Tanokura M.;
RT "Aspartate kinase-independent lysine synthesis in an extremely thermophilic
RT bacterium, Thermus thermophilus: lysine is synthesized via alpha-
RT aminoadipic acid not via diaminopimelic acid.";
RL J. Bacteriol. 181:1713-1718(1999).
RN [2]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=ATCC BAA-163 / DSM 7039 / HB27;
RX PubMed=15064768; DOI=10.1038/nbt956;
RA Henne A., Brueggemann H., Raasch C., Wiezer A., Hartsch T., Liesegang H.,
RA Johann A., Lienard T., Gohl O., Martinez-Arias R., Jacobi C.,
RA Starkuviene V., Schlenczeck S., Dencker S., Huber R., Klenk H.-P.,
RA Kramer W., Merkl R., Gottschalk G., Fritz H.-J.;
RT "The genome sequence of the extreme thermophile Thermus thermophilus.";
RL Nat. Biotechnol. 22:547-553(2004).
RN [3]
RP ROLE IN LYSINE BIOSYNTHESIS, AND PATHWAY.
RX PubMed=10613839; DOI=10.1101/gr.9.12.1175;
RA Nishida H., Nishiyama M., Kobashi N., Kosuge T., Hoshino T., Yamane H.;
RT "A prokaryotic gene cluster involved in synthesis of lysine through the
RT amino adipate pathway: a key to the evolution of amino acid biosynthesis.";
RL Genome Res. 9:1175-1183(1999).
RN [4]
RP FUNCTION, CATALYTIC ACTIVITY, SUBSTRATE SPECIFICITY, ACTIVITY REGULATION,
RP AND BIOPHYSICOCHEMICAL PROPERTIES.
RX PubMed=16524361; DOI=10.1042/bj20051711;
RA Jia Y., Tomita T., Yamauchi K., Nishiyama M., Palmer D.R.J.;
RT "Kinetics and product analysis of the reaction catalysed by recombinant
RT homoaconitase from Thermus thermophilus.";
RL Biochem. J. 396:479-485(2006).
CC -!- FUNCTION: Catalyzes the reversible hydration of cis-homoaconitate ((Z)-
CC but-1-ene-1,2,4-tricarboxylate) to homoisocitrate ((1R,2S)-1-
CC hydroxybutane-1,2,4-tricarboxylate). Can catalyze neither the
CC dehydration of (R)-homocitrate ((2R)-2-hydroxybutane-1,2,4-
CC tricarboxylate) into cis-homoaconitate in vitro, nor the reverse
CC reaction. Is not active toward (S)-homocitrate, cis-aconitate or
CC citrate as substrate. {ECO:0000269|PubMed:10613839,
CC ECO:0000269|PubMed:16524361}.
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; EC=4.2.1.36;
CC Evidence={ECO:0000269|PubMed:16524361};
CC -!- ACTIVITY REGULATION: Is not inhibited by lysine.
CC {ECO:0000269|PubMed:16524361}.
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=8.2 uM for cis-homoaconitate (at 60 degrees Celsius and pH 8)
CC {ECO:0000269|PubMed:16524361};
CC KM=36 uM for homoisocitrate (at 60 degrees Celsius and pH 8)
CC {ECO:0000269|PubMed:16524361};
CC pH dependence:
CC Optimum pH is 8.0. {ECO:0000269|PubMed:16524361};
CC -!- PATHWAY: Amino-acid biosynthesis; L-lysine biosynthesis via AAA
CC pathway; L-alpha-aminoadipate from 2-oxoglutarate: step 3/5.
CC {ECO:0000269|PubMed:10613839}.
CC -!- SUBUNIT: Heterodimer of HacA and HacB. {ECO:0000305}.
CC -!- SIMILARITY: Belongs to the LeuD family. {ECO:0000305}.
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DR EMBL; AB017109; BAA74763.1; -; mRNA.
DR EMBL; AE017221; AAS81888.1; -; Genomic_DNA.
DR RefSeq; WP_011173920.1; NC_005835.1.
DR AlphaFoldDB; Q9ZND9; -.
DR SMR; Q9ZND9; -.
DR STRING; 262724.TT_C1546; -.
DR EnsemblBacteria; AAS81888; AAS81888; TT_C1546.
DR KEGG; tth:TT_C1546; -.
DR eggNOG; COG0066; Bacteria.
DR HOGENOM; CLU_081378_1_1_0; -.
DR OMA; APFMVGE; -.
DR OrthoDB; 1384217at2; -.
DR BioCyc; MetaCyc:MON-6724; -.
DR SABIO-RK; Q9ZND9; -.
DR UniPathway; UPA00033; UER01027.
DR Proteomes; UP000000592; Chromosome.
DR GO; GO:0003861; F:3-isopropylmalate dehydratase activity; IEA:UniProtKB-UniRule.
DR GO; GO:0004409; F:homoaconitate hydratase activity; IEA:UniProtKB-EC.
DR GO; GO:0009098; P:leucine biosynthetic process; IEA:UniProtKB-UniRule.
DR GO; GO:0019878; P:lysine biosynthetic process via aminoadipic acid; IEA:UniProtKB-UniPathway.
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 1: Evidence at protein level;
KW Amino-acid biosynthesis; Lyase; Lysine biosynthesis.
FT CHAIN 1..163
FT /note="Homoaconitase small subunit"
FT /id="PRO_0000141954"
SQ SEQUENCE 163 AA; 18468 MW; 4B42935A3D3D194B CRC64;
MPRVWKFGDQ INTDDILPGK YAPFMVGEDR FHLYAFAHLR PEFAKEVRPG DILVFGRNAG
LGSSREYAPE ALKRLGVRAI IAKSYARIFF RNLVNLGIVP FESEEVVDAL EDGDEVELDL
ESGVLTRGEE RFALRPPPPF LLEALKEGSL LDYYKKHGRF PGE
