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O81852 (AKH2_ARATH) Reviewed, UniProtKB/Swiss-Prot

Last modified April 16, 2014. Version 109. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (3) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Alt products·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Bifunctional aspartokinase/homoserine dehydrogenase 2, chloroplastic

Short name=AK-HD 2
Short name=AK-HSDH 2
Alternative name(s):
Beta-aspartyl phosphate homoserine 2

Including the following 2 domains:

  1. Aspartokinase
    EC=2.7.2.4
  2. Homoserine dehydrogenase
    EC=1.1.1.3
Gene names
Name:AKHSDH2
Synonyms:AK-HSDH II
Ordered Locus Names:At4g19710
ORF Names:T16H5.70
OrganismArabidopsis thaliana (Mouse-ear cress) [Reference proteome]
Taxonomic identifier3702 [NCBI]
Taxonomic lineageEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaerosidsmalvidsBrassicalesBrassicaceaeCamelineaeArabidopsis

Protein attributes

Sequence length916 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Catalytic activity

L-homoserine + NAD(P)+ = L-aspartate 4-semialdehyde + NAD(P)H.

ATP + L-aspartate = ADP + 4-phospho-L-aspartate.

Enzyme regulation

Threonine interaction with Gln-443 leads to inhibition of aspartate kinase activity and facilitates the binding of a second threonine on Gln-524, leading to a partial inhibition of homoserine dehydrogenase activity (25% of activity remaining at saturation with threonine). Homoserine dehydrogenase activity is also partially inhibited by cysteine (15% of activity remaining at saturation with cysteine). No synergy between threonine and cysteine for the inhibition. 13-fold activation of aspartate kinase activity by cysteine, isoleucine, valine, serine and alanine at 2.5 mM and 4-fold activation by leucine at 2.5 mM, but no activation of homoserine dehydrogenase activity. Ref.5 Ref.6

Pathway

Amino-acid biosynthesis; L-lysine biosynthesis via DAP pathway; (S)-tetrahydrodipicolinate from L-aspartate: step 1/4.

Amino-acid biosynthesis; L-methionine biosynthesis via de novo pathway; L-homoserine from L-aspartate: step 1/3.

Amino-acid biosynthesis; L-methionine biosynthesis via de novo pathway; L-homoserine from L-aspartate: step 3/3.

Amino-acid biosynthesis; L-threonine biosynthesis; L-threonine from L-aspartate: step 1/5.

Amino-acid biosynthesis; L-threonine biosynthesis; L-threonine from L-aspartate: step 3/5.

Subunit structure

Homo- or heterodimer Potential.

Subcellular location

Plastidchloroplast.

Sequence similarities

In the N-terminal section; belongs to the aspartokinase family.

In the C-terminal section; belongs to the homoserine dehydrogenase family.

Contains 2 ACT domains.

Biophysicochemical properties

Kinetic parameters:

KM=11.6 mM for aspartate for the aspartokinase activity (in the presence of 40 mM ATP) Ref.3 Ref.6

KM=6.15 mM for aspartate for the aspartokinase activity (at pH 8.0, in the presence of 200 µM NADPH and 20 mM ATP)

KM=1.5 mM for aspartate for the aspartokinase activity (at pH 8.0, in the presence of 200 µM NADPH, 20 mM ATP and a saturating concentration of alanine)

KM=26.4 mM for aspartate for the aspartokinase activity (in the presence of 100 mM ATP and 0.5 mM threonine)

KM=5.5 mM for ATP for the aspartokinase activity (in the presence of 50 mM aspartate)

KM=2.2 mM for ATP for the aspartokinase activity (at pH 8.0, in the presence of 200 µM NADPH and 50 mM aspartate)

KM=0.42 mM for ATP for the aspartokinase activity (at pH 8.0, in the presence of 200 µM NADPH, 50 mM aspartate and a saturating concentration of alanine)

KM=5.2 mM for homoserine for the reverse reaction of the homoserine dehydrogenase activity (in the presence of 1 mM NADP)

KM=1.4 mM for aspartate semialdehyde for the forward reaction of the homoserine dehydrogenase activity (in the presence of NADPH)

KM=311 µM for aspartate semialdehyde for the forward reaction of the homoserine dehydrogenase activity (at pH 8.0, in the presence of 150 mM KCl and 200 µM NADPH)

KM=24.5 mM for homoserine for the reverse reaction of the homoserine dehydrogenase activity (in the presence of 1 mM NADP and 60 mM threonine)

KM=166.1 µM for NADP for the reverse reaction of the homoserine dehydrogenase activity (in the presence of 50 mM homoserine)

KM=676.1 µM for NADP for the reverse reaction of the homoserine dehydrogenase activity (in the presence of 100 mM homoserine and 60 mM threonine)

Vmax=5.4 µmol/min/mg enzyme toward aspartylhydroxamate for the aspartokinase activity

Vmax=165 µmol/min/mg enzyme toward aspartate semialdehyde for the forward reaction of the homoserine dehydrogenase activity

Vmax=18.8 µmol/min/mg enzyme toward NADPH for the reverse reaction of the homoserine dehydrogenase activity

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]
Isoform 1 (identifier: O81852-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.
Isoform 2 (identifier: O81852-2)

The sequence of this isoform differs from the canonical sequence as follows:
     837-916: LRYVGVVDAV...RLASYLGAPS → RLFTTNVFPFDQCDHILTIYICM
Note: Derived from EST data. No experimental confirmation available.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Transit peptide1 – 8787Chloroplast Potential
Chain88 – 916829Bifunctional aspartokinase/homoserine dehydrogenase 2, chloroplastic
PRO_0000245845

Regions

Domain412 – 48776ACT 1
Domain493 – 57078ACT 2
Nucleotide binding564 – 5696NADP Potential
Region88 – 336249Aspartokinase By similarity
Region337 – 562226Interface By similarity
Region563 – 916354Homoserine dehydrogenase By similarity

Natural variations

Alternative sequence837 – 91680LRYVG…LGAPS → RLFTTNVFPFDQCDHILTIY ICM in isoform 2.
VSP_019798

Experimental info

Mutagenesis4411I → A: Loss of threonine sensitivity for the aspartokinase activity and decreased inhibition of homoserine dehydrogenase activity by threonine. Ref.5
Mutagenesis4431Q → A: Loss of threonine sensitivity for the aspartokinase activity and decreased inhibition of homoserine dehydrogenase activity by threonine. Ref.5
Mutagenesis5221I → A: No effect on the inhibition of aspartokinase activity by threonine, but decreased inhibition of homoserine dehydrogenase activity by threonine. Ref.5
Mutagenesis5241Q → A: No effect on the inhibition of aspartokinase activity by threonine, but decreased inhibition of homoserine dehydrogenase activity by threonine. Ref.5

Sequences

Sequence LengthMass (Da)Tools
Isoform 1 [UniParc].

Last modified November 1, 1998. Version 1.
Checksum: 7ECD984DAFC97C4F

FASTA916100,250
        10         20         30         40         50         60 
MATLKPSFTV SPPNSNPIRF GSFPPQCFLR VPKPRRLILP RFRKTTGGGG GLIRCELPDF 

        70         80         90        100        110        120 
HLSATATTVS GVSTVNLVDQ VQIPKGEMWS VHKFGGTCVG NSQRIRNVAE VIINDNSERK 

       130        140        150        160        170        180 
LVVVSAMSKV TDMMYDLIRK AQSRDDSYLS ALEAVLEKHR LTARDLLDGD DLASFLSHLH 

       190        200        210        220        230        240 
NDISNLKAML RAIYIAGHAS ESFSDFVAGH GELWSAQMLS YVVRKTGLEC KWMDTRDVLI 

       250        260        270        280        290        300 
VNPTSSNQVD PDFGESEKRL DKWFSLNPSK IIIATGFIAS TPQNIPTTLK RDGSDFSAAI 

       310        320        330        340        350        360 
MGALLRARQV TIWTDVDGVY SADPRKVNEA VILQTLSYQE AWEMSYFGAN VLHPRTIIPV 

       370        380        390        400        410        420 
MRYNIPIVIR NIFNLSAPGT IICQPPEDDY DLKLTTPVKG FATIDNLALI NVEGTGMAGV 

       430        440        450        460        470        480 
PGTASDIFGC VKDVGANVIM ISQASSEHSV CFAVPEKEVN AVSEALRSRF SEALQAGRLS 

       490        500        510        520        530        540 
QIEVIPNCSI LAAVGQKMAS TPGVSCTLFS ALAKANINVR AISQGCSEYN VTVVIKREDS 

       550        560        570        580        590        600 
VKALRAVHSR FFLSRTTLAM GIVGPGLIGA TLLDQLRDQA AVLKQEFNID LRVLGITGSK 

       610        620        630        640        650        660 
KMLLSDIGID LSRWRELLNE KGTEADLDKF TQQVHGNHFI PNSVVVDCTA DSAIASRYYD 

       670        680        690        700        710        720 
WLRKGIHVIT PNKKANSGPL DQYLKLRDLQ RKSYTHYFYE ATVGAGLPII STLRGLLETG 

       730        740        750        760        770        780 
DKILRIEGIC SGTLSYLFNN FVGDRSFSEV VTEAKNAGFT EPDPRDDLSG TDVARKVIIL 

       790        800        810        820        830        840 
ARESGLKLDL ADLPIRSLVP EPLKGCTSVE EFMEKLPQYD GDLAKERLDA ENSGEVLRYV 

       850        860        870        880        890        900 
GVVDAVNQKG TVELRRYKKE HPFAQLAGSD NIIAFTTTRY KDHPLIVRGP GAGAQVTAGG 

       910 
IFSDILRLAS YLGAPS 

« Hide

Isoform 2 [UniParc].

Checksum: 1785CFCBF23709C7
Show »

FASTA85994,426

References

« Hide 'large scale' references
[1]"Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana."
Mayer K.F.X., Schueller C., Wambutt R., Murphy G., Volckaert G., Pohl T., Duesterhoeft A., Stiekema W., Entian K.-D., Terryn N., Harris B., Ansorge W., Brandt P., Grivell L.A., Rieger M., Weichselgartner M., de Simone V., Obermaier B. expand/collapse author list , Mache R., Mueller M., Kreis M., Delseny M., Puigdomenech P., Watson M., Schmidtheini T., Reichert B., Portetelle D., Perez-Alonso M., Boutry M., Bancroft I., Vos P., Hoheisel J., Zimmermann W., Wedler H., Ridley P., Langham S.-A., McCullagh B., Bilham L., Robben J., van der Schueren J., Grymonprez B., Chuang Y.-J., Vandenbussche F., Braeken M., Weltjens I., Voet M., Bastiaens I., Aert R., Defoor E., Weitzenegger T., Bothe G., Ramsperger U., Hilbert H., Braun M., Holzer E., Brandt A., Peters S., van Staveren M., Dirkse W., Mooijman P., Klein Lankhorst R., Rose M., Hauf J., Koetter P., Berneiser S., Hempel S., Feldpausch M., Lamberth S., Van den Daele H., De Keyser A., Buysshaert C., Gielen J., Villarroel R., De Clercq R., van Montagu M., Rogers J., Cronin A., Quail M.A., Bray-Allen S., Clark L., Doggett J., Hall S., Kay M., Lennard N., McLay K., Mayes R., Pettett A., Rajandream M.A., Lyne M., Benes V., Rechmann S., Borkova D., Bloecker H., Scharfe M., Grimm M., Loehnert T.-H., Dose S., de Haan M., Maarse A.C., Schaefer M., Mueller-Auer S., Gabel C., Fuchs M., Fartmann B., Granderath K., Dauner D., Herzl A., Neumann S., Argiriou A., Vitale D., Liguori R., Piravandi E., Massenet O., Quigley F., Clabauld G., Muendlein A., Felber R., Schnabl S., Hiller R., Schmidt W., Lecharny A., Aubourg S., Chefdor F., Cooke R., Berger C., Monfort A., Casacuberta E., Gibbons T., Weber N., Vandenbol M., Bargues M., Terol J., Torres A., Perez-Perez A., Purnelle B., Bent E., Johnson S., Tacon D., Jesse T., Heijnen L., Schwarz S., Scholler P., Heber S., Francs P., Bielke C., Frishman D., Haase D., Lemcke K., Mewes H.-W., Stocker S., Zaccaria P., Bevan M., Wilson R.K., de la Bastide M., Habermann K., Parnell L., Dedhia N., Gnoj L., Schutz K., Huang E., Spiegel L., Sekhon M., Murray J., Sheet P., Cordes M., Abu-Threideh J., Stoneking T., Kalicki J., Graves T., Harmon G., Edwards J., Latreille P., Courtney L., Cloud J., Abbott A., Scott K., Johnson D., Minx P., Bentley D., Fulton B., Miller N., Greco T., Kemp K., Kramer J., Fulton L., Mardis E., Dante M., Pepin K., Hillier L.W., Nelson J., Spieth J., Ryan E., Andrews S., Geisel C., Layman D., Du H., Ali J., Berghoff A., Jones K., Drone K., Cotton M., Joshu C., Antonoiu B., Zidanic M., Strong C., Sun H., Lamar B., Yordan C., Ma P., Zhong J., Preston R., Vil D., Shekher M., Matero A., Shah R., Swaby I.K., O'Shaughnessy A., Rodriguez M., Hoffman J., Till S., Granat S., Shohdy N., Hasegawa A., Hameed A., Lodhi M., Johnson A., Chen E., Marra M.A., Martienssen R., McCombie W.R.
Nature 402:769-777(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
Strain: cv. Columbia.
[2]The Arabidopsis Information Resource (TAIR)
Submitted (APR-2011) to the EMBL/GenBank/DDBJ databases
Cited for: GENOME REANNOTATION.
Strain: cv. Columbia.
[3]"Overproduction, purification, and characterization of recombinant bifunctional threonine-sensitive aspartate kinase-homoserine dehydrogenase from Arabidopsis thaliana."
Paris S., Wessel P.M., Dumas R.
Protein Expr. Purif. 24:105-110(2002) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1), BIOPHYSICOCHEMICAL PROPERTIES.
[4]"Whole genome sequence comparisons and 'full-length' cDNA sequences: a combined approach to evaluate and improve Arabidopsis genome annotation."
Castelli V., Aury J.-M., Jaillon O., Wincker P., Clepet C., Menard M., Cruaud C., Quetier F., Scarpelli C., Schaechter V., Temple G., Caboche M., Weissenbach J., Salanoubat M.
Genome Res. 14:406-413(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 1).
Strain: cv. Columbia.
[5]"Mechanism of control of Arabidopsis thaliana aspartate kinase-homoserine dehydrogenase by threonine."
Paris S., Viemon C., Curien G., Dumas R.
J. Biol. Chem. 278:5361-5366(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: ENZYME REGULATION, MUTAGENESIS OF ILE-441; GLN-443; ILE-522 AND GLN-524.
[6]"Identification of six novel allosteric effectors of Arabidopsis thaliana aspartate kinase-homoserine dehydrogenase isoforms. Physiological context sets the specificity."
Curien G., Ravanel S., Robert M., Dumas R.
J. Biol. Chem. 280:41178-41183(2005) [PubMed] [Europe PMC] [Abstract]
Cited for: ENZYME REGULATION, BIOPHYSICOCHEMICAL PROPERTIES.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AL024486 Genomic DNA. Translation: CAA19688.1.
AL161551 Genomic DNA. Translation: CAB78973.1.
CP002687 Genomic DNA. Translation: AEE84219.1.
CP002687 Genomic DNA. Translation: AEE84220.1.
BX827863 mRNA. No translation available.
PIRT04752.
RefSeqNP_193706.2. NM_118091.3.
NP_974576.1. NM_202847.2.
UniGeneAt.32787.

3D structure databases

ProteinModelPortalO81852.
SMRO81852. Positions 90-551, 554-912.
ModBaseSearch...
MobiDBSearch...

Proteomic databases

PaxDbO81852.
PRIDEO81852.

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Genome annotation databases

EnsemblPlantsAT4G19710.2; AT4G19710.2; AT4G19710. [O81852-1]
GeneID827715.
KEGGath:AT4G19710.

Organism-specific databases

TAIRAT4G19710.

Phylogenomic databases

eggNOGCOG0527.
HOGENOMHOG000271593.
InParanoidO81852.
KOK12524.
OMAIFISQAS.
PhylomeDBO81852.
ProtClustDBCLSN2682367.

Enzyme and pathway databases

BioCycARA:GQT-2291-MONOMER.
BRENDA1.1.1.3. 399.
SABIO-RKO81852.
UniPathwayUPA00034; UER00015.
UPA00050; UER00063.
UPA00050; UER00461.
UPA00051; UER00462.
UPA00051; UER00465.

Gene expression databases

ArrayExpressO81852.
GenevestigatorO81852.

Family and domain databases

Gene3D3.40.1160.10. 2 hits.
3.40.50.720. 1 hit.
InterProIPR002912. ACT_dom.
IPR001048. Asp/Glu/Uridylate_kinase.
IPR005106. Asp/hSer_DH_NAD-bd.
IPR001341. Asp_kinase_dom.
IPR018042. Aspartate_kinase_CS.
IPR011147. Bifunc_aspartokin/hSer_DH.
IPR001342. HDH_cat.
IPR019811. HDH_CS.
IPR016040. NAD(P)-bd_dom.
[Graphical view]
PfamPF00696. AA_kinase. 1 hit.
PF01842. ACT. 2 hits.
PF00742. Homoserine_dh. 1 hit.
PF03447. NAD_binding_3. 1 hit.
[Graphical view]
PIRSFPIRSF000727. ThrA. 1 hit.
SUPFAMSSF53633. SSF53633. 1 hit.
TIGRFAMsTIGR00657. asp_kinases. 1 hit.
PROSITEPS51671. ACT. 2 hits.
PS00324. ASPARTOKINASE. 1 hit.
PS01042. HOMOSER_DHGENASE. 1 hit.
[Graphical view]
ProtoNetSearch...

Entry information

Entry nameAKH2_ARATH
AccessionPrimary (citable) accession number: O81852
Secondary accession number(s): Q3E9Y8
Entry history
Integrated into UniProtKB/Swiss-Prot: July 11, 2006
Last sequence update: November 1, 1998
Last modified: April 16, 2014
This is version 109 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

PATHWAY comments

Index of metabolic and biosynthesis pathways

Arabidopsis thaliana

Arabidopsis thaliana: entries and gene names