1fwk
CRYSTAL STRUCTURE OF HOMOSERINE KINASE COMPLEXED WITH ADP
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| , resolution 2.1Å | |||||||
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| Ligands: | and | ||||||
| Activity: | Homoserine kinase, with EC number 2.7.1.39 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
BACKGROUND: Homoserine kinase (HSK) catalyzes an important step in the threonine biosynthesis pathway. It belongs to a large yet unique class of small metabolite kinases, the GHMP kinase superfamily. Members in the GHMP superfamily participate in several essential metabolic pathways, such as amino acid biosynthesis, galactose metabolism, and the mevalonate pathway. RESULTS: The crystal structure of HSK and its complex with ADP reveal a novel nucleotide binding fold. The N-terminal domain contains an unusual left-handed betaalphabeta unit, while the C-terminal domain has a central alpha-beta plait fold with an insertion of four helices. The phosphate binding loop in HSK is distinct from the classical P loops found in many ATP/GTP binding proteins. The bound ADP molecule adopts a rare syn conformation and is in the opposite orientation from those bound to the P loop-containing proteins. Inspection of the substrate binding cavity indicates several amino acid residues that are likely to be involved in substrate binding and catalysis. CONCLUSIONS: The crystal structure of HSK is the first representative in the GHMP superfamily to have determined structure. It provides insight into the structure and nucleotide binding mechanism of not only the HSK family but also a variety of enzymes in the GHMP superfamily. Such enzymes include galactokinases, mevalonate kinases, phosphomevalonate kinases, mevalonate pyrophosphate decarboxylases, and several proteins of yet unknown functions.
About this StructureAbout this Structure
1FWK is a Single protein structure of sequence from Methanocaldococcus jannaschii. Full crystallographic information is available from OCA.
ReferenceReference
Structure and mechanism of homoserine kinase: prototype for the GHMP kinase superfamily., Zhou T, Daugherty M, Grishin NV, Osterman AL, Zhang H, Structure. 2000 Dec 15;8(12):1247-57. PMID:11188689
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