Experts and Doctors on x ray crystallography in Irvine, California, United States


Locale: Irvine, California, United States
Topic: x ray crystallography

Top Publications

  1. Bonagura C, Bhaskar B, Shimizu H, Li H, Sundaramoorthy M, McRee D, et al. High-resolution crystal structures and spectroscopy of native and compound I cytochrome c peroxidase. Biochemistry. 2003;42:5600-8 pubmed
    ..87 A, suggesting a single Fe(IV)-O bond and not the generally accepted double bond. ..
  2. Larson S, Day J, Barba de la Rosa A, Keen N, McPherson A. First crystallographic structure of a xylanase from glycoside hydrolase family 5: implications for catalysis. Biochemistry. 2003;42:8411-22 pubmed
    ..The first 13 N-terminal residues form one beta-strand of this domain. Residues 44, 45, and 316-322 form the linkers between this domain and the catalytic domain. ..
  3. Meharenna Y, Oertel P, Bhaskar B, Poulos T. Engineering ascorbate peroxidase activity into cytochrome c peroxidase. Biochemistry. 2008;47:10324-32 pubmed publisher
    ..While wild-type CCP shows no APX activity, CCP2APX catalyzes the peroxidation of ascorbate at a rate of approximately 12 min (-1), indicating that the engineered ascorbate-binding loop can bind ascorbate. ..
  4. Korman T, Tan Y, Wong J, Luo R, Tsai S. Inhibition kinetics and emodin cocrystal structure of a type II polyketide ketoreductase. Biochemistry. 2008;47:1837-47 pubmed publisher
    ..The results lay the foundation for the design of novel aromatic polyketide natural products with different reduction patterns. ..
  5. Khakshoor O, Lin A, Korman T, Sawaya M, Tsai S, Eisenberg D, et al. X-ray crystallographic structure of an artificial beta-sheet dimer. J Am Chem Soc. 2010;132:11622-8 pubmed publisher
  6. Chamberland S, Ziller J, Woerpel K. Structural evidence that alkoxy substituents adopt electronically preferred pseudoaxial orientations in six-membered ring dioxocarbenium ions. J Am Chem Soc. 2005;127:5322-3 pubmed
  7. Yoshizawa J, Blank M, Fay A, Lee C, Wiig J, Hu Y, et al. Optimization of FeMoco maturation on NifEN. J Am Chem Soc. 2009;131:9321-5 pubmed publisher
  8. Herron S, Scavetta R, Garrett M, Legner M, Jurnak F. Characterization and implications of Ca2+ binding to pectate lyase C. J Biol Chem. 2003;278:12271-7 pubmed
    ..At saturating Ca(2+) concentrations, PelC activity increases 10-fold at pH 4.5 but is less than 1% of maximal activity at pH 9.5. Taken together, the studies suggest that the primary Ca(2+) ion in PelC has multiple functions. ..
  9. Sevrioukova I, Poulos T, Churbanova I. Crystal structure of the putidaredoxin reductase x putidaredoxin electron transfer complex. J Biol Chem. 2010;285:13616-20 pubmed publisher

More Information


  1. Larson S, Day J, McPherson A. X-ray crystallographic analyses of pig pancreatic alpha-amylase with limit dextrin, oligosaccharide, and alpha-cyclodextrin. Biochemistry. 2010;49:3101-15 pubmed publisher
    ..By comprehensive integration of these complexes we have constructed a model for the binding of polysaccharides having the helical character known to be present in natural substrates such as starch and glycogen. ..
  2. Meharenna Y, Doukov T, Li H, Soltis S, Poulos T. Crystallographic and single-crystal spectral analysis of the peroxidase ferryl intermediate. Biochemistry. 2010;49:2984-6 pubmed publisher
    ..The low-dose structure correlates well with an Fe(IV) horizontal lineO bond, while we postulate that the high-dose structure is the cryo-trapped Fe(III)-OH species previously thought to be an Fe(IV)-OH species. ..
  3. Barrows T, Bhaskar B, Poulos T. Electrostatic control of the tryptophan radical in cytochrome c peroxidase. Biochemistry. 2004;43:8826-34 pubmed
    ..When taken together, these results demonstrate a strong correlation between the experimentally determined stability of the Trp191 radical, the enzyme activity, and the calculated electrostatic stabilization of the Trp191 radical. ..
  4. Churbanova I, Poulos T, Sevrioukova I. Production and characterization of a functional putidaredoxin reductase-putidaredoxin covalent complex. Biochemistry. 2010;49:58-67 pubmed publisher
  5. Martin D, Vanderwal C. Efficient access to the core of the Strychnos, Aspidosperma and Iboga alkaloids. A short synthesis of norfluorocurarine. J Am Chem Soc. 2009;131:3472-3 pubmed publisher
    ..This powerful reaction is showcased in a five-step synthesis of the Strychnos alkaloid norfluorocurarine from tryptamine and pyridine...
  6. Dounay A, Humphreys P, Overman L, Wrobleski A. Total synthesis of the strychnos alkaloid (+)-minfiensine: tandem enantioselective intramolecular Heck-iminium ion cyclization. J Am Chem Soc. 2008;130:5368-77 pubmed publisher
    ..A distinctive feature of this sequence is the use of palladium-catalyzed reactions to form all carbon-carbon bonds in the transformation of these simple precursors to (+)-minfiensine...
  7. Li C, Koter M, Ye X, Zhou S, Chou W, Luo R, et al. Widespread but small-scale changes in the structural and dynamic properties of vaccinia virus poly(A) polymerase upon association with its processivity factor in solution. Biochemistry. 2010;49:6247-62 pubmed publisher
  8. Ho W, Li H, Nishida C, de Montellano P, Poulos T. Crystal structure and properties of CYP231A2 from the thermoacidophilic archaeon Picrophilus torridus. Biochemistry. 2008;47:2071-9 pubmed publisher
    ..The increase in thermal stability instead is best correlated with the smaller size and shorter loops in CYP231A2 compared to other P450s...
  9. Korman T, Hill J, Vu T, Tsai S. Structural analysis of actinorhodin polyketide ketoreductase: cofactor binding and substrate specificity. Biochemistry. 2004;43:14529-38 pubmed publisher
    ..The structures of act KR provide an important step toward understanding aromatic PKS and will enhance our ability to design novel aromatic polyketide natural products with different reduction patterns...
  10. Gao Sheridan H, Kemper M, Khayat R, Tilley G, Armstrong F, Sridhar V, et al. A T14C variant of Azotobacter vinelandii ferredoxin I undergoes facile [3Fe-4S]0 to [4Fe-4S]2+ conversion in vitro but not in vivo. J Biol Chem. 1998;273:33692-701 pubmed
    ..However, unlike native FdI which does not undergo facile cluster conversion, the 7Fe form T14C FdI quickly converts to the 8Fe form with a high efficiency under reducing conditions. ..
  11. Friedman J, Lad L, Li H, Wilks A, Poulos T. Structural basis for novel delta-regioselective heme oxygenation in the opportunistic pathogen Pseudomonas aeruginosa. Biochemistry. 2004;43:5239-45 pubmed
  12. Friedman J, Lad L, Deshmukh R, Li H, Wilks A, Poulos T. Crystal structures of the NO- and CO-bound heme oxygenase from Neisseriae meningitidis. Implications for O2 activation. J Biol Chem. 2003;278:34654-9 pubmed
    ..Although the active site residues differ between nm-HO and human HO-1, the close similarity in the H-bonded water network suggests a common mechanism shared by all heme oxygenases. ..
  13. Cartailler J, Luecke H. X-ray crystallographic analysis of lipid-protein interactions in the bacteriorhodopsin purple membrane. Annu Rev Biophys Biomol Struct. 2003;32:285-310 pubmed
    ..A brief discussion of the possibility that bacteriorhodopsin functions as a light-driven inward hydroxide pump rather than an outward proton pump is also presented...
  14. Chen K, Jung Y, Bonagura C, Tilley G, Prasad G, Sridhar V, et al. Azotobacter vinelandii ferredoxin I: a sequence and structure comparison approach to alteration of [4Fe-4S]2+/+ reduction potential. J Biol Chem. 2002;277:5603-10 pubmed
  15. Schuller D, Zhu W, Stojiljkovic I, Wilks A, Poulos T. Crystal structure of heme oxygenase from the gram-negative pathogen Neisseria meningitidis and a comparison with mammalian heme oxygenase-1. Biochemistry. 2001;40:11552-8 pubmed
    ..Key glycine residues provide the flexibility for the helical kink, allow close contact of the helix backbone with the heme, and may interact directly with heme ligands...
  16. Kuznetsov Y, Larson S, Day J, Greenwood A, McPherson A. Structural transitions of satellite tobacco mosaic virus particles. Virology. 2001;284:223-34 pubmed
    ..Evidence is also presented that preparations of native virus and their crystals are naturally somewhat heterogeneous and contain a variety of particles of anomalous size...
  17. Yano J, Koo L, Schuller D, Li H, Ortiz de Montellano P, Poulos T. Crystal structure of a thermophilic cytochrome P450 from the archaeon Sulfolobus solfataricus. J Biol Chem. 2000;275:31086-92 pubmed publisher
    ..An additional feature of the 4-phenylimidazole-bound structure is a zinc ion tetrahedrally bound by symmetry-related His and Glu residues...
  18. Schuller D, Wilks A, Ortiz de Montellano P, Poulos T. Crystal structure of human heme oxygenase-1. Nat Struct Biol. 1999;6:860-7 pubmed
    ..Regioselective oxygenation of the alpha-meso heme carbon is due primarily to steric influence of the distal helix. ..
  19. Swartz L, Kuchinskas M, Li H, Poulos T, Lanzilotta W. Redox-dependent structural changes in the Azotobacter vinelandii bacterioferritin: new insights into the ferroxidase and iron transport mechanism. Biochemistry. 2006;45:4421-8 pubmed
    ..Taken together, these data allow a molecular movie of the ferroxidase gating mechanism to be developed and provide further insight into the iron uptake and/or release and mineralization mechanism of bacterioferritins in general...
  20. Lad L, Friedman J, Li H, Bhaskar B, Ortiz de Montellano P, Poulos T. Crystal structure of human heme oxygenase-1 in a complex with biliverdin. Biochemistry. 2004;43:3793-801 pubmed
    ..Biliverdin adopts a more linear conformation and moves from the heme site to an internal cavity. These structural results provide insight into the rate-limiting step in HO-1 catalysis, which is product, biliverdin, release. ..
  21. Chen K, Bonagura C, Tilley G, McEvoy J, Jung Y, Armstrong F, et al. Crystal structures of ferredoxin variants exhibiting large changes in [Fe-S] reduction potential. Nat Struct Biol. 2002;9:188-92 pubmed
    ..The smaller (50--100 mV) increases observed for the neutral form are proposed to occur by directing a Hdelta+--Ndelta- dipole toward the reduced form of the cluster. ..
  22. Smith P, Zhou B, Ho N, Yuan Y, Su L, Tsai S, et al. 2.6 A X-ray crystal structure of human p53R2, a p53-inducible ribonucleotide reductase . Biochemistry. 2009;48:11134-41 pubmed publisher
    ..Insight gained from this structural work will be used in the identification of biological function, regulation mechanism, and inhibitor selection in RNR small subunits. ..
  23. Raman C, Li H, Martasek P, Southan G, Masters B, Poulos T. Crystal structure of nitric oxide synthase bound to nitro indazole reveals a novel inactivation mechanism. Biochemistry. 2001;40:13448-55 pubmed
    ..We also present three crystal structures that reveal how alterations at the substrate site facilitate 7-NIBr and structurally dissimilar ligands to occupy the cofactor site. ..
  24. Dioumaev A, Brown L, Needleman R, Lanyi J. Coupling of the reisomerization of the retinal, proton uptake, and reprotonation of Asp-96 in the N photointermediate of bacteriorhodopsin. Biochemistry. 2001;40:11308-17 pubmed
    ..The reisomerization of the retinal occurs only after recovery from a long-living protein conformation in which reprotonation of Asp-96 is either entirely blocked or blocked at low pH. ..
  25. Delker S, Ji H, Li H, Jamal J, Fang J, Xue F, et al. Unexpected binding modes of nitric oxide synthase inhibitors effective in the prevention of a cerebral palsy phenotype in an animal model. J Am Chem Soc. 2010;132:5437-42 pubmed publisher
    ..A new hot spot generated as a result of enzyme elasticity provides important information for the future fragment-based design of selective NOS inhibitors. ..