1tl7
Complex Of Gs- With The Catalytic Domains Of Mammalian Adenylyl Cyclase: Complex With 2'(3')-O-(N-methylanthraniloyl)-guanosine 5'-triphosphate and Mn
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OverviewOverview
Membrane-bound mammalian adenylyl cyclase (mAC) catalyzes the synthesis of, intracellular cyclic AMP from ATP and is activated by stimulatory G, protein alpha subunits (Galpha(s)) and by forskolin (FSK). mACs are, inhibited with high potency by 2 '(3')-O-(N-methylanthraniloyl), (MANT)-substituted nucleotides. In this study, the crystal structures of, the complex between Galpha(s).GTPgammaS and the catalytic C1 and C2, domains from type V and type II mAC (VC1.IIC2), bound to FSK and either, MANT-GTP.Mg(2+) or MANT-GTP.Mn(2+) have been determined. MANT-GTP, coordinates two metal ions and occupies the same position in the catalytic, site as P-site inhibitors and substrate analogs. However, the orientation, of the guanine ring is reversed relative to that of the adenine ring. The, MANT fluorophore resides in a hydrophobic pocket at the interface between, the VC1 and IIC2 domains and prevents mAC from undergoing the "open" to, "closed" domain rearrangement. The K(i) of MANT-GTP for inhibition of, VC1.IIC2 is lower in the presence of mAC activators and lower in the, presence of Mn(2+) compared with Mg(2+), indicating that the inhibitor, binds more tightly to the catalytically most active form of the enzyme., Fluorescence resonance energy transfer-stimulated emission from the MANT, fluorophore upon excitation of Trp-1020 in the MANT-binding pocket of IIC2, is also stronger in the presence of FSK. Mutational analysis of two, non-conserved amino acids in the MANT-binding pocket suggests that, residues outside of the binding site influence isoform selectivity toward, MANT-GTP.
About this StructureAbout this Structure
1TL7 is a Protein complex structure of sequences from Bos taurus, Canis lupus familiaris and Rattus norvegicus with MG, CL, MN, GSP, FOK and ONM as ligands. Active as Adenylate cyclase, with EC number 4.6.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for the inhibition of mammalian membrane adenylyl cyclase by 2 '(3')-O-(N-Methylanthraniloyl)-guanosine 5 '-triphosphate., Mou TC, Gille A, Fancy DA, Seifert R, Sprang SR, J Biol Chem. 2005 Feb 25;280(8):7253-61. Epub 2004 Dec 9. PMID:15591060
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