UniProtKB - P09339 (ACNA_BACSU)
Protein
Aconitate/2-methylaconitate hydratase
Gene
citB
Organism
Bacillus subtilis (strain 168)
Status
Functioni
Involved in both the tricarboxylic acid (TCA) and methylcitric acid cycles (PubMed:28956599). Catalyzes the reversible isomerization of citrate to isocitrate via cis-aconitate (PubMed:3110133, PubMed:23354745). Also catalyzes the rehydration of 2-methyl-cis-aconitate to produce 2-methylisocitrate (PubMed:28956599). The apo form of AcnA functions as a RNA-binding regulatory protein which plays a role in the regulation of citrate concentration and in the sporulation. To prevent the accumulation of excessive levels of citrate, it binds near the 5' end of the citZ mRNA, decreasing its stability and thereby limiting the concentration of citrate synthase in the cell. Aconitase also binds to the gerE transcript late in sporulation and stabilizes it for translation, thereby increasing the rate and level of GerE protein accumulation (PubMed:10468622, PubMed:16923907, PubMed:23354745, PubMed:9393699).6 Publications
Miscellaneous
Whether aconitase is active as an enzyme or an RNA-binding protein is determined by the status of an iron-sulfur (4Fe-4S) cluster that is essential for the catalytic activity of all aconitases. Citrate is both cotransported with iron and a chelator of divalent cations, including iron. If the intracellular citrate level becomes excessive, iron will be sequestered away from iron-containing proteins, including aconitase. Since excess citrate greatly stimulates aconitase synthesis via the positive regulatory effect of CcpC, the cell will gain the ability to metabolize citrate at a higher rate. If so much iron has been sequestered that aconitase loses enzymatic activity, the cell will acquire a high concentration of enzymatically inactive but RNA-binding-competent aconitase molecules. These aconitase proteins can bind to the citZ mRNA and reduce the rate of citrate accumulation by restricting the synthesis of citrate synthase protein.2 Publications
Catalytic activityi
- EC:4.2.1.31 Publication
Cofactori
[4Fe-4S] cluster1 PublicationNote: Binds 1 [4Fe-4S] cluster per subunit.1 Publication
: tricarboxylic acid cycle Pathwayi
This protein is involved in step 2 of the subpathway that synthesizes isocitrate from oxaloacetate.1 PublicationProteins known to be involved in the 2 steps of the subpathway in this organism are:
- Citrate synthase 2 (citZ), Citrate synthase 1 (citA), Citrate/2-methylcitrate synthase (mmgD)
- Aconitate hydratase (acnA), Aconitate/2-methylaconitate hydratase (citB)
View all proteins of this organism that are known to be involved in the subpathway that synthesizes isocitrate from oxaloacetate, the pathway tricarboxylic acid cycle and in Carbohydrate metabolism.
Sites
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Metal bindingi | 450 | Iron-sulfur (4Fe-4S)By similarity | 1 | |
Metal bindingi | 516 | Iron-sulfur (4Fe-4S)By similarity | 1 | |
Metal bindingi | 519 | Iron-sulfur (4Fe-4S)By similarity | 1 |
GO - Molecular functioni
- 2-methylisocitrate dehydratase activity Source: UniProtKB
- 4 iron, 4 sulfur cluster binding Source: UniProtKB
- aconitate hydratase activity Source: UniProtKB
- citrate dehydratase activity Source: UniProtKB-EC
- metal ion binding Source: UniProtKB-KW
- mRNA 3'-UTR binding Source: UniProtKB
- mRNA binding Source: UniProtKB
GO - Biological processi
- citrate metabolic process Source: GO_Central
- propionate metabolic process, methylcitrate cycle Source: UniProtKB
- regulation of sporulation Source: UniProtKB
- tricarboxylic acid cycle Source: GO_Central
Keywordsi
Molecular function | Lyase, RNA-binding |
Biological process | Tricarboxylic acid cycle |
Ligand | Iron, Iron-sulfur, Metal-binding |
Enzyme and pathway databases
BioCyci | BSUB:BSU18000-MONOMER |
UniPathwayi | UPA00223;UER00718 |
Names & Taxonomyi
Protein namesi | Recommended name: Aconitate/2-methylaconitate hydratase1 Publication (EC:4.2.1.-1 Publication, EC:4.2.1.31 Publication)Alternative name(s): Aconitate hydratase A1 Publication Short name: ACN1 Publication Short name: Aconitase1 Publication Iron-responsive protein-like1 Publication Short name: IRP-like1 Publication RNA-binding protein1 Publication |
Gene namesi | Name:citB Ordered Locus Names:BSU18000 |
Organismi | Bacillus subtilis (strain 168) |
Taxonomic identifieri | 224308 [NCBI] |
Taxonomic lineagei | Bacteria › Firmicutes › Bacilli › Bacillales › Bacillaceae › Bacillus › |
Proteomesi |
|
Pathology & Biotechi
Disruption phenotypei
Cells lacking this gene show a dramatic increase in the concentration of citrate. This accumulation of citrate prevents sporulation due to chelation by citrate of divalent cations required for proper functioning of the Spo0A-initiated phosphorelay.1 Publication
Mutagenesis
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Mutagenesisi | 450 | C → S: Loss of aconitase activity. It is glutamate auxotroph and accumulates citrate. Exhibits overexpression of the citB promoter and accumulates high levels of inactive aconitase. 1 Publication | 1 | |
Mutagenesisi | 741 | R → E: Same aconitase activity compared to the wild-type. It is glutamate prototroph and accumulates citrate. Exhibits overexpression of the citB promoter and accumulates high levels of active aconitase. 1 Publication | 1 |
PTM / Processingi
Molecule processing
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Initiator methioninei | Removed1 Publication | |||
ChainiPRO_0000076655 | 2 – 909 | Aconitate/2-methylaconitate hydrataseAdd BLAST | 908 |
Proteomic databases
jPOSTi | P09339 |
PaxDbi | P09339 |
PRIDEi | P09339 |
Expressioni
Inductioni
By citrate via CcpC. When citrate is absent, CcpC binds to the sites near the citB promoter and blocks expression. When citrate is present, it causes a change in the interaction of CcpC with its binding sites, resulting in derepression of citB. When citrate is very abundant, CcpC activates citB expression, presumably reflecting a change in the interaction of CcpC with RNA polymerase. Also induced by decoyinine and nutrient depletion.1 Publication
Interactioni
Subunit structurei
Monomer.
1 PublicationProtein-protein interaction databases
IntActi | P09339, 1 interactor |
MINTi | P09339 |
STRINGi | 224308.BSU18000 |
Family & Domainsi
Domaini
Mutagenesis of different positions (F662L, R741F, Q745E, I810T and V853A) on the C-terminal region of citB gene product shows that even B.subtilis mutant has high aconitase catalytic activity, it is defective in sporulation. The defect is at a late stage of sporulation, specifically affecting expression of sigma-K-dependent genes, many of which are important for spore coat assembly and require transcriptional activation by GerE. It strongly suggests that aconitase RNA binding activity may stabilize gerE mRNA in order to allow efficient GerE synthesis and proper timing of spore coat assembly.1 Publication
Sequence similaritiesi
Belongs to the aconitase/IPM isomerase family.Curated
Phylogenomic databases
eggNOGi | COG1048, Bacteria |
InParanoidi | P09339 |
OMAi | NGGIMQY |
PhylomeDBi | P09339 |
Family and domain databases
CDDi | cd01580, AcnA_IRP_Swivel, 1 hit |
Gene3Di | 3.20.19.10, 1 hit 3.30.499.10, 1 hit |
InterProi | View protein in InterPro IPR044137, AcnA_IRP_Swivel IPR015931, Acnase/IPM_dHydase_lsu_aba_1/3 IPR001030, Acoase/IPM_deHydtase_lsu_aba IPR015928, Aconitase/3IPM_dehydase_swvl IPR006249, Aconitase/IRP2 IPR018136, Aconitase_4Fe-4S_BS IPR036008, Aconitase_4Fe-4S_dom IPR000573, AconitaseA/IPMdHydase_ssu_swvl |
PANTHERi | PTHR11670, PTHR11670, 1 hit |
Pfami | View protein in Pfam PF00330, Aconitase, 1 hit PF00694, Aconitase_C, 1 hit |
PRINTSi | PR00415, ACONITASE |
SUPFAMi | SSF53732, SSF53732, 1 hit |
TIGRFAMsi | TIGR01341, aconitase_1, 1 hit |
PROSITEi | View protein in PROSITE PS00450, ACONITASE_1, 1 hit PS01244, ACONITASE_2, 1 hit |
i Sequence
Sequence statusi: Complete.
: The displayed sequence is further processed into a mature form. Sequence processingi
P09339-1 [UniParc]FASTAAdd to basket
10 20 30 40 50
MANEQKTAAK DVFQARKTFT TNGKTYHYYS LKALEDSGIG KVSKLPYSIK
60 70 80 90 100
VLLESVLRQV DGFVIKKEHV ENLAKWGTAE LKDIDVPFKP SRVILQDFTG
110 120 130 140 150
VPAVVDLASL RKAMAAVGGD PDKINPEIPV DLVIDHSVQV DKAGTEDALA
160 170 180 190 200
VNMDLEFERN AERYKFLSWA KKAFNNYQAV PPATGIVHQV NLEFLASVVH
210 220 230 240 250
AIEEDGELVT YPDTLVGTDS HTTMINGIGV LGWGVGGIEA EAGMLGQPSY
260 270 280 290 300
FPVPEVIGAK LVGKLPNGTT ATDLALKVTQ VLREKGVVGK FVEFFGPGIA
310 320 330 340 350
ELPLADRATI ANMAPEYGAT CGFFPVDEEA LNYLRLTGRD PEHIDVVEAY
360 370 380 390 400
CRSNGLFYTP DAEDPQFTDV VEIDLSQIEA NLSGPKRPQD LIPLSAMQET
410 420 430 440 450
FKKQLVSPAG NQGFGLNAEE ENKEIKFKLL NGEETVMKTG AIAIAAITSC
460 470 480 490 500
TNTSNPYVLI GAGLVAKKAV ELGLKVPNYV KTSLAPGSKV VTGYLVNSGL
510 520 530 540 550
LPYMKELGFN LVGYGCTTCI GNSGPLSPEI EEAVAKNDLL ITSVLSGNRN
560 570 580 590 600
FEGRIHPLVK GNYLASPPLV VAYALAGTVN INLKTDPIGV GKDGQNVYFN
610 620 630 640 650
DIWPSMDEIN ALVKQTVTPE LFRKEYETVF DDNKRWNEIE TTDEALYKWD
660 670 680 690 700
NDSTYIQNPP FFEEMSVEPG KVEPLKGLRV VGKFGDSVTT DHISPAGAIG
710 720 730 740 750
KDTPAGKYLQ EKGVSPRDFN SYGSRRGNHE VMMRGTFANI RIKNQIAPGT
760 770 780 790 800
EGGFTTYWPT GEVTSIYDAC MKYKEDKTGL VVLAGKDYGM GSSRDWAAKG
810 820 830 840 850
TNLLGIRTVI AESFERIHRS NLVFMGVLPL QFKQGENADT LGLTGKEVIE
860 870 880 890 900
VDVDETVRPR DLVTVRAINE DGNVTTFEAV VRFDSEVEID YYRHGGILQM
VLREKMKQS
Experimental Info
Feature key | Position(s) | DescriptionActions | Graphical view | Length |
---|---|---|---|---|
Sequence conflicti | 43 – 45 | SKL → FEA in AAA22316 (PubMed:3110133).Curated | 3 | |
Sequence conflicti | 119 | G → V no nucleotide entry (Ref. 3) Curated | 1 |
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | Z73234 Genomic DNA Translation: CAA97599.1 AL009126 Genomic DNA Translation: CAB13684.1 M16776 Genomic DNA Translation: AAA22316.1 |
PIRi | G69599 |
RefSeqi | NP_389683.1, NC_000964.3 WP_003245728.1, NZ_JNCM01000035.1 |
Genome annotation databases
EnsemblBacteriai | CAB13684; CAB13684; BSU_18000 |
GeneIDi | 938140 |
KEGGi | bsu:BSU18000 |
PATRICi | fig|224308.179.peg.1961 |
Similar proteinsi
Cross-referencesi
Sequence databases
Select the link destinations: EMBLi GenBanki DDBJi Links Updated | Z73234 Genomic DNA Translation: CAA97599.1 AL009126 Genomic DNA Translation: CAB13684.1 M16776 Genomic DNA Translation: AAA22316.1 |
PIRi | G69599 |
RefSeqi | NP_389683.1, NC_000964.3 WP_003245728.1, NZ_JNCM01000035.1 |
3D structure databases
SMRi | P09339 |
ModBasei | Search... |
Protein-protein interaction databases
IntActi | P09339, 1 interactor |
MINTi | P09339 |
STRINGi | 224308.BSU18000 |
Proteomic databases
jPOSTi | P09339 |
PaxDbi | P09339 |
PRIDEi | P09339 |
Genome annotation databases
EnsemblBacteriai | CAB13684; CAB13684; BSU_18000 |
GeneIDi | 938140 |
KEGGi | bsu:BSU18000 |
PATRICi | fig|224308.179.peg.1961 |
Phylogenomic databases
eggNOGi | COG1048, Bacteria |
InParanoidi | P09339 |
OMAi | NGGIMQY |
PhylomeDBi | P09339 |
Enzyme and pathway databases
UniPathwayi | UPA00223;UER00718 |
BioCyci | BSUB:BSU18000-MONOMER |
Family and domain databases
CDDi | cd01580, AcnA_IRP_Swivel, 1 hit |
Gene3Di | 3.20.19.10, 1 hit 3.30.499.10, 1 hit |
InterProi | View protein in InterPro IPR044137, AcnA_IRP_Swivel IPR015931, Acnase/IPM_dHydase_lsu_aba_1/3 IPR001030, Acoase/IPM_deHydtase_lsu_aba IPR015928, Aconitase/3IPM_dehydase_swvl IPR006249, Aconitase/IRP2 IPR018136, Aconitase_4Fe-4S_BS IPR036008, Aconitase_4Fe-4S_dom IPR000573, AconitaseA/IPMdHydase_ssu_swvl |
PANTHERi | PTHR11670, PTHR11670, 1 hit |
Pfami | View protein in Pfam PF00330, Aconitase, 1 hit PF00694, Aconitase_C, 1 hit |
PRINTSi | PR00415, ACONITASE |
SUPFAMi | SSF53732, SSF53732, 1 hit |
TIGRFAMsi | TIGR01341, aconitase_1, 1 hit |
PROSITEi | View protein in PROSITE PS00450, ACONITASE_1, 1 hit PS01244, ACONITASE_2, 1 hit |
ProtoNeti | Search... |
MobiDBi | Search... |
Entry informationi
Entry namei | ACNA_BACSU | |
Accessioni | P09339Primary (citable) accession number: P09339 Secondary accession number(s): Q45059 | |
Entry historyi | Integrated into UniProtKB/Swiss-Prot: | July 1, 1989 |
Last sequence update: | January 23, 2007 | |
Last modified: | April 7, 2021 | |
This is version 154 of the entry and version 4 of the sequence. See complete history. | ||
Entry statusi | Reviewed (UniProtKB/Swiss-Prot) | |
Annotation program | Prokaryotic Protein Annotation Program |
Miscellaneousi
Keywords - Technical termi
Direct protein sequencing, Reference proteomeDocuments
- PATHWAY comments
Index of metabolic and biosynthesis pathways - SIMILARITY comments
Index of protein domains and families