Reviewed, UniProtKB/Swiss-Prot O23653 (AK2_ARATH)

Names and origin

Protein names

Recommended name:
    Aspartokinase 2, chloroplastic
    EC=2.7.2.4
Alternative name(s):
    Aspartate kinase 2

Gene names

Name:	AK2
Synonyms:	AK-LYS2, CARAB-AK-LYS
Ordered Locus Names:	At5g14060
ORF Names:	MUA22.6

Organism

Arabidopsis thaliana (Mouse-ear cress) [Complete proteome]

Taxonomic identifier

3702 [NCBI]

Taxonomic lineage

Eukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › eudicotyledons › core eudicotyledons › rosids › eurosids II › Brassicales › Brassicaceae › Arabidopsis

Protein attributes

Sequence length	544 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Involved in the first step of essential amino acids lysine, threonine, methionine and isoleucine synthesis via the aspartate-family pathway.
Catalytic activity	ATP + L-aspartate = ADP + 4-phospho-L-aspartate.
Enzyme regulation	Allosterically inhibited by lysine, but not by S-adenosyl-L-methionine (SAM). K(0.5) for lysine in the presence of physiological concentrations of substrates is 12.5 µM. No inhibition by threonine or leucine and no activation or inhibition by alanine, cysteine, isoleucine, serine, valine, methionine, glutamine, asparagine, glutamic acid or arginine. Ref.4
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-threonine biosynthesis; L-threonine from L-aspartate: step 1/5.
Subcellular location	Plastid › chloroplast Potential.
Tissue specificity	Expressed in stems, leaves, floral organs and young seedlings. Ref.1
Sequence similarities	Belongs to the aspartokinase family. Contains 2 ACT domains.
Biophysicochemical properties	Kinetic parameters: K(cat) is 14.5/sec. KM=980 µM for ATP KM=1940 µM for aspartate

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Threonine biosynthesis
Cellular component	Chloroplast Plastid
Domain	Repeat Transit peptide
Ligand	ATP-binding Nucleotide-binding
Molecular function	Kinase Transferase
Technical term	Complete proteome
Gene Ontology (GO)
Biological process	threonine biosynthetic process Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	chloroplast Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular function	ATP binding Inferred from electronic annotation. Source: UniProtKB-KW amino acid binding Inferred from electronic annotation. Source: InterPro aspartate kinase activity Inferred from electronic annotation. Source: EC
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Transit peptide	1 – 84	84	Chloroplast Potential
	Chain	85 – 544	460	Aspartokinase 2, chloroplastic		PRO_0000248158
Regions
	Domain	402 – 477	76	ACT 1
	Domain	478 – 539	62	ACT 2
Sites
	Binding site	87	1	ATP By similarity
	Binding site	90	1	ATP; via amide nitrogen By similarity
	Binding site	119	1	ATP By similarity
	Binding site	203	1	Substrate By similarity
Experimental info
	Sequence conflict	94	1	E → G in AAB63104. Ref.1
	Sequence conflict	94	1	E → G in CAC06395. Ref.2
	Sequence conflict	107	1	L → F in AAB63104. Ref.1
	Sequence conflict	107	1	L → F in CAC06395. Ref.2
	Sequence conflict	125	1	T → I in AAB63104. Ref.1
	Sequence conflict	125	1	T → I in CAC06395. Ref.2
	Sequence conflict	144	1	E → G in AAB63104. Ref.1

Sequences

	Sequence		Length	Mass (Da)
	O23653-1 [UniParc]. Last modified September 5, 2006. Version 2. Checksum: 7DBCFDC1138645AC	FASTA	544	59,605
	10 20 30 40 50 60 MASLQLYGVK TPGLALSSKR LEFASKGACF SVTLPSSSAV FRDVEHSCRN IGLRVSCEAL 70 80 90 100 110 120 RVDLLQRKEP ETCDSSGTGK ELTCVMKFGG SSVESAERMK EVANLILSFP DERPVIVLSA 130 140 150 160 170 180 MGKTTNKLLK AGEKAVTCGV TNVESIEELS FIKELHLRTA HELGVETTVI EKHLEGLHQL 190 200 210 220 230 240 LKGISMMKEL TLRTRDYLVS FGECMSTRLF SAYLNKIGHK ARQYDAFEIG FITTDDFTNA 250 260 270 280 290 300 DILEATYPAV SKTLVGDWSK ENAVPVVTGY LGKGWRSCAI TTLGRGGSDL TATTIGKALG 310 320 330 340 350 360 LREIQVWKDV DGVLTCDPNI YPGAQSVPYL TFDEAAELAY FGAQVLHPLS MRPARDGDIP 370 380 390 400 410 420 VRVKNSYNPT APGTVITRSR DMSKAVLTSI VLKRNVTMLD IASTRMLGQY GFLAKVFTTF 430 440 450 460 470 480 EDLGISVDVV ATSEVSISLT LDPAKLWGRE LIQRVNELDN LVEELEKIAV VKLLQRRSII 490 500 510 520 530 540 SLIGNVQKSS LILEKVFQVF RSNGVNVQMI SQGASKVNIS LIVNDEEAEQ CVRALHSAFF ETDP

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Cloning and expression of an Arabidopsis thaliana cDNA encoding a monofunctional aspartate kinase homologous to the lysine-sensitive enzyme of Escherichia coli." Tang G., Zhu-Shimoni J.X., Amir R., Zchori I.B.-T., Galili G. Plant Mol. Biol. 34:287-293(1997) [PubMed: 9207844] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY.
[2]	Frankard V.M.S., Vauterin M., Jacobs M. Submitted (JAN-1998) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: cv. Columbia. Tissue: Leaf.
[3]	"Structural analysis of Arabidopsis thaliana chromosome 5. III. Sequence features of the regions of 1,191,918 bp covered by seventeen physically assigned P1 clones." Nakamura Y., Sato S., Kaneko T., Kotani H., Asamizu E., Miyajima N., Tabata S. DNA Res. 4:401-414(1997) [PubMed: 9501997] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Columbia.
[4]	"Allosteric monofunctional aspartate kinases from Arabidopsis." Curien G., Laurencin M., Robert-Genthon M., Dumas R. FEBS J. 274:164-176(2007) [PubMed: 17140415] [Abstract] Cited for: BIOPHYSICOCHEMICAL PROPERTIES, ENZYME REGULATION.
+	Additional computationally mapped references.

Cross-references

Sequence databases
EMBLGenBankDDBJ	U62020 mRNA. Translation: AAB63104.1. Y16255 Genomic DNA. Translation: CAC06395.1. AB007650 Genomic DNA. Translation: BAB08285.1.
IPI	IPI00527711.
RefSeq	NP_001078581.1. NP_196910.1.
UniGene	At.21761
3D structure databases
SMR	O23653. Positions 80-542.
ModBase	Search...
Protein-protein interaction databases
STRING	O23653.
Proteomic databases
PRIDE	O23653.
Genome annotation databases
GeneID	831255.
GenomeReviews	Gene locus AT5G14060 in contig BA000015_GR.
KEGG	ath:AT5G14060.
NMPDR	fig|3702.1.peg.23535.
Organism-specific databases
TAIR	At5g14060.
Phylogenomic databases
OMA	KLSCLFM.
Enzyme and pathway databases
BRENDA	2.7.2.4. 302.
Gene expression databases
Genevestigator	O23653.
GermOnline	AT5G14060. Arabidopsis thaliana.
Family and domain databases
InterPro	IPR002912. ACT_bd. IPR001048. Asp/Glu/Uridylate_kinase. IPR001341. Asp_kin_reg. IPR018042. Aspartate_kinase_CS. [Graphical view]
Gene3D	G3DSA:3.40.1160.10. Aa_kinase. 1 hit.
Pfam	PF00696. AA_kinase. 1 hit. PF01842. ACT. 2 hits. [Graphical view]
TIGRFAMs	TIGR00657. asp_kinases. 1 hit.
PROSITE	PS00324. ASPARTOKINASE. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

AK2_ARATH

Accession

Primary (citable) accession number: O23653
Secondary accession number(s): Q9FMU4, Q9FY44

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 5, 2006
Last sequence update:	September 5, 2006
Last modified:	November 3, 2009
This is version 58 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

PPAP (Plant Proteome Annotation Project)