Itoh Group Literature Review

Dr. Virginia M. Cangelosi,  Dr. Aniruddha Deb,  Prof. James E. Penner-Hahn and Prof. Vincent L. Pecoraro Abstract Protein design will ultimately allow for the creation of artificial enzymes with novel functions and unprecedented stability. To test our current mastery of nature’s approach to catalysis, a Zn II  metalloenzyme was prepared using de novo design. α 3 DH 3  folds into a stable single-stranded three-helix bundle and binds Zn II  with high affinity using His 3 O coordination. The resulting metalloenzyme catalyzes the hydration of CO 2  better than any small molecule model of carbonic anhydrase and with an efficiency within 1400-fold of the fastest carbonic anhydrase isoform, CAII, and 11-fold of CAIII. Chasing down the cheetah : A synthetic metalloenzyme was created that is capable of catalyzing the hydration of carbon dioxide with an efficiency within 1400-fold of carbonic anhydrase II, one of the most efficient enzymes known. This ...

Bojana Ginovska-Pangovska   ,  Arnab Dutta   , Matthew L. Reback   ,  John C. Linehan   , and  Wendy J. Shaw   * Pacific Northwest National Laboratory , Richland, Washington 99354,  United States Acc. Chem. Res. , Article ASAP DOI:  10.1021/ar5001742 Publication Date (Web): June 19, 2014 Copyright © 2014 American Chemical Society Abstract 注目の系。 View:  ACS ActiveView PDF  |  PDF  |  PDF w/ Links  |  Full Text HTML

Simon Turega   ,  William Cullen   ,  Martina Whitehead   , Christopher A. Hunter   * , and  Michael D. Ward   * Department of Chemistry,  University of Sheffield , Sheffield S3 7HF,  U.K. Abstract Size and shape criteria for guest binding inside the cavity of an octanuclear cubic coordination cage in water have been established using a new fluorescence displacement assay to quantify guest binding. For aliphatic cyclic ketones of increasing size (from C 5  to C 11 ), there is a linear relationship between Δ G  for guest binding and the guest’s surface area: the change in Δ G  for binding is 0.3 kJ mol –1  Å –2 , corresponding to 5 kJ mol –1  for each additional CH 2  group in the guest, in good agreement with expectations based on hydrophobic desolvation. The highest association constant is  K  = 1.2 × 10 6  M –1  for cycloundecanone, whose volume is approximately 50% of the...

Christopher C. Farwell   ,  John A. McIntosh   ,  Todd K. Hyster   ,  Z. Jane Wang   , and  Frances H. Arnold   * Division of Chemistry and Chemical Engineering 210-41,  California Institute of Technology , 1200 East California Blvd, Pasadena, California 91125,  United States Abstract Engineering enzymes with novel reaction modes promises to expand the applications of biocatalysis in chemical synthesis and will enhance our understanding of how enzymes acquire new functions. The insertion of nitrogen-containing functional groups into unactivated C–H bonds is not catalyzed by known enzymes but was recently demonstrated using engineered variants of cytochrome P450 BM3  (CYP102A1) from  Bacillus megaterium . Here, we extend this novel P450-catalyzed reaction to include intermolecular insertion of nitrogen into thioethers to form sulfimides. An examination of the reactivity of different P450 BM3  variants tow...

Timothy H. Yosca   ,  Rachel K. Behan   ,  Courtney M. Krest   ,  Elizabeth L. Onderko   ,  Matthew C. Langston , and  Michael T. Green   * Department of Chemistry,  Pennsylvania State University , University Park, State College, Pennsylvania 16802,  United States To provide insight into the iron(IV)hydroxide p K a  of histidine ligated heme proteins, we have probed the active site of myoglobin compound II over the pH range of 3.9–9.5, using EXAFS, Mössbauer, and resonance Raman spectroscopies. We find no indication of ferryl protonation over this pH range, allowing us to set an upper limit of 2.7 on the iron(IV)hydroxide p K a  in myoglobin. Together with the recent determination of an iron(IV)hydroxide p K a    12 in the thiolate-ligated heme enzyme cytochrome P450, this result provides insight into Nature’s ability to tune catalytic function through its choice of axial ligand.

Yang Ha   † ,  Adam L. Tenderholt   † ,  Richard H. Holm * § ,  Britt Hedman   * ‡ ,  Keith O. Hodgson   * † ‡ , and Edward I. Solomon   * † ‡ †  Department of Chemistry,  Stanford University , Stanford, California 94305,  United States ‡  Stanford Synchrotron Radiation Lightsource, SLAC, Stanford University , Menlo Park, California 94025, United States §  Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations have been used to determine the electronic structures of two complexes [Mo IV O(bdt) 2 ] 2–  and [Mo VI O 2 (bdt) 2 ] 2–  (bdt = benzene-1,2-dithiolate(2−)) that relate to the reduced and oxidized forms of sulfite oxidase (SO). These are compared with those of previously studied dimethyl sulfoxide reductase (DMSOr) models. DFT calcul...

76  Journal of the American Chemical Society: Latest Articles (ACS Publications)  by Meghan C. McCormick, Karlijn Keijzer, Abhigna Polavarapu, Franklin A. Schultz and Mu-Hyun Baik  /   7d   //   keep unread   //   hide   //  preview Journal of the American Chemical Society DOI: 10.1021/ja5029765 Six-coordinate Pt(IV)-complexes are prominent prodrug candidates for the treatment of various cancers where, upon two-electron reduction and loss of two axial ligands, they form more familiar, pharmacologically active four-coordinate Pt(II) drugs. A series of electrochemical experiments coupled with extensive density functional calculations has been employed to elucidate the mechanism for the two-electron reduction of Pt IV (NH 3 ) 2 Cl 2 L 2  to Pt II (NH 3 ) 2 Cl 2  (L = CH 3 COO – ,  1 ; L = CHCl 2 COO – ,  2 ; L = Cl – ,  3 ). A reliable estimate for the normal reduction po...

Article Previous Article Next Article Articles ASAP Four-Coordinate Cobalt Pincer Complexes: Electronic Structure Studies and Ligand Modification by Homolytic and Heterolytic Pathways ACS ActiveView PDF Hi-Res Print, Annotate, Reference QuickView PDF  [3491 KB] PDF w/ Links [688 KB] Full Text HTML Abstract Supporting Info -> Figures Reference QuickView Add to ACS ChemWorx Scott P. Semproni   ,  Carsten Milsmann   , and  Paul J. Chirik   * Department of Chemistry,  Princeton University , Princeton, New Jersey 08544,  United States J. Am. Chem. Soc. , Article ASAP DOI:  10.1021/ja504334a Publication Date (Web): June 4, 2014 Copyright © 2014 American Chemical Society pchirik@princeton.edu Section: Physical Organic Chemistry Abstract A family of cobalt chloride, methyl, acetylide and hydride complexes bearing both intact and modified  tert -butyl substituted bis(pho...

Edge Article Speciation and decomposition pathways of ruthenium catalysts used for selective C–H hydroxylation Cornelia Flender , a      Ashley M. Adams , a      Jennifer L. Roizen , a    Eric McNeill , a      J. Du Bois * a  and     Richard N. Zare * a    Show Affiliations Chem. Sci. , 2014, Advance Article DOI:  10.1039/C4SC01050G Received 10 Apr 2014, Accepted 02 Jun 2014 First published online 17 Jun 2014 | | Share on citeulike | Share on facebook | Share on twitter | | More PDF Rich HTML    Send PDF to Kindle Download Citation BibTex   EndNote   MEDLINE   ProCite   ReferenceManager   RefWorks   RIS   Request Permissions Abstract Cited by Related Content   Mechanistic insight into a C–H hydroxylation reaction catalysed by [(Me 3 tacn)RuCl 3 ] has been obtained ...

Angewandte Chemie International Edition  by Oliver Krahe, Eckhard Bill, Frank Neese  /   30d   //   keep unread  //   hide   //   preview Abstract Cryogenically trapped Fe V  nitride complexes with cyclam-based ligands were found to decay by bimolecular reactions, forming exclusively Fe II  compounds. Characterization of educts and products by Mössbauer spectroscopy, mass spectrometry, and spectroscopy-oriented DFT calculations showed that the reaction mechanism is reductive nitride coupling and release of dinitrogen (2 Fe V N→Fe II -NN-Fe II →2 Fe II +N 2 ). The reaction pathways, representing an “inverse” of the Haber–Bosch reaction, were computationally explored in detail, also to judge the feasibility of yielding catalytically competent Fe V (N). Implications for the photolytic cleavage of Fe III  azides used to generate high-valent Fe nitrides are discussed. Always look on the bri...