2i6b
From Proteopedia
Human Adenosine Kinase in Complex with An Acetylinic Inhibitor
Structural highlights
DiseaseADK_HUMAN Defects in ADK are the cause of hypermethioninemia due to adenosine kinase deficiency (HMAKD) [MIM:614300. A metabolic disorder characterized by global developmental delay, early-onset seizures, mild dysmorphic features, and characteristic biochemical anomalies, including persistent hypermethioninemia with increased levels of S-adenosylmethionine and S-adenosylhomocysteine. Homocysteine levels are typically normal.[1] FunctionADK_HUMAN ATP dependent phosphorylation of adenosine and other related nucleoside analogs to monophosphate derivatives. Serves as a potential regulator of concentrations of extracellular adenosine and intracellular adenine nucleotides. 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 PubMedAdenosine kinase (AK) is an enzyme responsible for converting endogenous adenosine (ADO) to adenosine monophosphate (AMP) in an adenosine triphosphate- (ATP-) dependent manner. The structure of AK consists of two domains, the first a large alpha/beta Rossmann-like nucleotide binding domain that forms the ATP binding site, and a smaller mixed alpha/beta domain, which, in combination with the larger domain, forms the ADO binding site and the site of phosphoryl transfer. AK inhibitors have been under investigation as antinociceptive, antiinflammatory, and anticonvulsant as well as antiinfective agents. In this work, we report the structures of AK in complex with two classes of inhibitors: the first, ADO-like, and the second, a novel alkynylpyrimidine series. The two classes of structures, which contain structurally similar substituents, reveal distinct binding modes in which the AK structure accommodates the inhibitor classes by a 30 degrees rotation of the small domain relative to the large domain. This change in binding mode stabilizes an open and a closed intermediate structural state and provide structural insight into the transition required for catalysis. This results in a significant rearrangement of both the protein active site and the orientation of the alkynylpyrimidine ligand when compared to the observed orientation of nucleosidic inhibitors or substrates. Crystal structures of human adenosine kinase inhibitor complexes reveal two distinct binding modes.,Muchmore SW, Smith RA, Stewart AO, Cowart MD, Gomtsyan A, Matulenko MA, Yu H, Severin JM, Bhagwat SS, Lee CH, Kowaluk EA, Jarvis MF, Jakob CL J Med Chem. 2006 Nov 16;49(23):6726-31. PMID:17154503[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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