1m8j

Crystal Structure Of Methanobacterium Thermoautotrophicum Nicotinamide Mononucleotide Adenylyltransferase Mutant R136A complexed with NAD

spinqualitylabelsall models 1m8j, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1m8j is a 1 chain structure with sequence from "methanobacterium_thermoautotrophicus"_(sic)_zeikus_and_wolfe_1972 "methanobacterium thermoautotrophicus" (sic) zeikus and wolfe 1972. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NAD, SO4 Related: 1m8f, 1m8g, 1m8k Gene: mth0150 ("Methanobacterium thermoautotrophicus" (sic) Zeikus and Wolfe 1972) Activity: Nicotinamide-nucleotide adenylyltransferase, with EC number 2.7.7.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum 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 PubMed Several residues lining the ATP-binding site of Methanobacterium thermoautotrophicum nicotinamide mononucleotide adenylyltransferase (NMNATase) were mutated in an effort to better characterize their roles in substrate binding and catalysis. Residues selected were Arg-11 and Arg-136, both of which had previously been implicated as substrate binding residues, as well as His-16 and His-19, part of the HXGH active site motif and postulated to be of importance in catalysis. Kinetic studies revealed that both Arg-11 and Arg-136 contributed to the binding of the substrate, ATP. When these amino acids were replaced by lysines, the apparent Km values of the respective mutants for ATP decreased by factors of 1.3 and 2.9 and by factors of 1.9 and 8.8 when the same residues were changed to alanines. All four Arg mutants displayed unaltered Km values for NMN. The apparent kcat values of the R11K and R136K mutants were the same as those of WT NMNATase but the apparent kcat values of the alanine mutants had decreased. Crystal structures of the Arg mutants revealed NAD+ and SO42- molecules trapped at their active sites. The binding interactions of NAD+ were unchanged but the binding of SO42- was altered in these mutants compared with wild type. The alanine mutants at positions His-16 and His-19 retained approximately 6 and 1.3%, respectively, of WT NMNATase activity indicating that His-19 is a key catalytic group. Surprisingly, this H19A mutant displayed a novel and distinct mode of NAD+ binding when co-crystallized in the presence of NAD+ and SO42-. Mutational, structural, and kinetic studies of the ATP-binding site of Methanobacterium thermoautotrophicum nicotinamide mononucleotide adenylyltransferase.,Saridakis V, Pai EF J Biol Chem. 2003 Sep 5;278(36):34356-63. Epub 2003 Jun 16. PMID:12810729 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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