2b3r
Crystal structure of the C2 domain of class II phosphatidylinositide 3-kinase C2
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OverviewOverview
Phosphatidylinositide (PtdIns) 3-kinase catalyzes the addition of a phosphate group to the 3'-position of phosphatidyl inositol. Accumulated evidence shows that PtdIns 3-kinase can provide a critical signal for cell proliferation, cell survival, membrane trafficking, glucose transport, and membrane ruffling. Mammalian PtdIns 3-kinases are divided into three classes based on structure and substrate specificity. A unique characteristic of class II PtdIns 3-kinases is the presence of both a phox homolog domain and a C2 domain at the C terminus. The biological function of the C2 domain of the class II PtdIns 3-kinases remains to be determined. We have determined the crystal structure of the mCPK-C2 domain, which is the first three-dimensional structural model of a C2 domain of class II PtdIns 3-kinases. Structural studies reveal that the mCPK-C2 domain has a typical anti-parallel beta-sandwich fold. Scrutiny of the surface of this C2 domain has identified three small, shallow sulfate-binding sites. On the basis of the structural features of these sulfate-binding sites, we have studied the lipid binding properties of the mCPK-C2 domain by site-directed mutagenesis. Our results show that this C2 domain binds specifically to PtdIns(3,4)P(2) and PtdIns(4,5)P(2) and that three lysine residues at SBS I site, Lys-1420, Lys-1432, and Lys-1434, are responsible for the phospholipid binding affinity.
About this StructureAbout this Structure
2B3R is a Single protein structure of sequence from Mus musculus with as ligand. Active as Phosphatidylinositol-4-phosphate 3-kinase, with EC number 2.7.1.154 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the C2 domain of class II phosphatidylinositide 3-kinase C2alpha., Liu L, Song X, He D, Komma C, Kita A, Virbasius JV, Huang G, Bellamy HD, Miki K, Czech MP, Zhou GW, J Biol Chem. 2006 Feb 17;281(7):4254-60. Epub 2005 Dec 7. PMID:16338929
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