2iew | pdb_00002iew
Crystal structure of Inositol Phosphate Multikinase Ipk2 from S. cerevisiae
Structural highlights
Function[IPMK_YEAST] Has kinase activity and phosphorylates inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4). Has low kinase activity towards InsP6. With ARG80, ARG81 and MCM1, coordinates the expression of arginine anabolic and catabolic genes in response to arginine. Recruites ARG80 and MCM21 to stabilize them.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedInositol polyphosphates perform essential functions as second messengers in eukaryotic cells, and their cellular levels are regulated by inositol phosphate kinases. Most of these enzymes belong to the inositol phosphate kinase superfamily, which consists of three subgroups, inositol 3-kinases, inositol phosphate multikinases, and inositol hexakisphosphate kinases. Family members share several strictly conserved signature motifs and are expected to have the same backbone fold, despite very limited overall amino acid sequence identity. Sequence differences are expected to play important roles in defining the different substrate selectivity of these enzymes. To investigate the structural basis for substrate specificity, we have determined the crystal structure of the yeast inositol phosphate multikinase Ipk2 in the apoform and in a complex with ADP and Mn(2+) at up to 2.0A resolution. The overall structure of Ipk2 is related to inositol trisphosphate 3-kinase. The ATP binding site is similar in both enzymes; however, the inositol binding domain is significantly smaller in Ipk2. Replacement of critical side chains in the inositolbinding site suggests how modification of substrate recognition motifs determines enzymatic substrate preference and catalysis. Crystal structure of inositol phosphate multikinase 2 and implications for substrate specificity.,Holmes W, Jogl G J Biol Chem. 2006 Dec 8;281(49):38109-16. Epub 2006 Oct 18. PMID:17050532[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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