Medicine and Health Sciences Commons^™

A Gga Plus U Approach To Effective Electronic Correlations In Thiolate-Ligated Iron-Oxo (Iv) Porphyrin, Justin Elenewski, John C. Hackett

Medicinal Chemistry Publications

High-valent oxo-metal complexes exhibit correlated electronic behavior on dense, low-lying electronic state manifolds, presenting challenging systems for electronic structure methods. Among these species, the iron-oxo (IV) porphyrin denoted Compound I occupies a privileged position, serving a broad spectrum of catalytic roles. The most reactive members of this family bear a thiolate axial ligand, exhibiting high activity toward molecular oxygen activation and substrate oxidation. The default approach to such systems has entailed the use of hybrid density functionals or multi-configurational/multireference methods to treat electronic correlation. An alternative approach is presented based on the GGA+U approximation to density functional theory, in …

On The Specificity Of Heparin/Heparan Sulfate Binding To Proteins. Anion-Binding Sites On Antithrombin And Thrombin Are Fundamentally Different, Philip D. Mosier, Chandravel Krishnasamy, Glen E. Kellogg, Umesh R. Desai

Medicinal Chemistry Publications

Background

The antithrombin–heparin/heparan sulfate (H/HS) and thrombin–H/HS interactions are recognized as prototypic specific and non-specific glycosaminoglycan (GAG)–protein interactions, respectively. The fundamental structural basis for the origin of specificity, or lack thereof, in these interactions remains unclear. The availability of multiple co-crystal structures facilitates a structural analysis that challenges the long-held belief that the GAG binding sites in antithrombin and thrombin are essentially similar with high solvent exposure and shallow surface characteristics.

Methodology

Analyses of solvent accessibility and exposed surface areas, gyrational mobility, symmetry, cavity shape/size, conserved water molecules and crystallographic parameters were performed for 12 X-ray structures, which include 12 …

Pyridoxal 5′-Phosphate Is A Slow Tight Binding Inhibitor Of E. Coli Pyridoxal Kinase, Mohini S. Ghatge, Roberto Contestabile, Martino L. Di Salvo, Jigar V. Desai, Amit Gandhi, Christina M. Camara, Rita Florio, Isabel N. Gonzalez, Alessia Parroni, Verne Schirch, Martin A. Safo

Medicinal Chemistry Publications

Pyridoxal 5′-phosphate (PLP) is a cofactor for dozens of B6 requiring enzymes. PLP reacts with apo-B6 enzymes by forming an aldimine linkage with the ε-amino group of an active site lysine residue, thus yielding the catalytically active holo-B6 enzyme. During protein turnover, the PLP is salvaged by first converting it to pyridoxal by a phosphatase and then back to PLP by pyridoxal kinase. Nonetheless, PLP poses a potential toxicity problem for the cell since its reactive 4′-aldehyde moiety forms covalent adducts with other compounds and non-B6 proteins containing thiol or amino groups. The regulation of PLP homeostasis in the cell …

Crystal Structures Of Human Pyridoxal Kinase In Complex With The Neurotoxins, Ginkgotoxin And Theophylline: Insights Into Pyridoxal Kinase Inhibition, Amit Gandhi, Jigar V. Desai, Mohini S. Ghatge, Martino L. Di Salvo, Stefano Di Biase, Richmond Danso-Danquah, Faik N. Musayev, Roberto Contestabile, Verne Schirch, Martin A. Safo

Medicinal Chemistry Publications

Several drugs and natural compounds are known to be highly neurotoxic, triggering epileptic convulsions or seizures, and causing headaches, agitations, as well as other neuronal symptoms. The neurotoxic effects of some of these compounds, including theophylline and ginkgotoxin, have been traced to their inhibitory activity against human pyridoxal kinase (hPL kinase), resulting in deficiency of the active cofactor form of vitamin B6, pyridoxal 5′-phosphate (PLP). Pyridoxal (PL), an inactive form of vitamin B6 is converted to PLP by PL kinase. PLP is the B6 vitamer required as a cofactor for over 160 enzymatic activities essential in primary and secondary metabolism. …

Design, Synthesis, And In Vitro And In Vivo Biological Studies Of A 3′-Deoxythymidine Conjugate That Potentially Kills Cancer Cells Selectively, Qiong Wei, Dejun Zhang, Anna Yao, Liyi Mai, Zhiwei Zhang, Qibing Zhou

Medicinal Chemistry Publications

Thymidine kinases (TKs) have been considered one of the potential targets for anticancer therapeutic because of their elevated expressions in cancer cells. However, nucleobase analogs targeting TKs have shown poor selective cytotoxicity in cancer cells despite effective antiviral activity. 3′-Deoxythymidine phenylquinoxaline conjugate (dT-QX) was designed as a novel nucleobase analog to target TKs in cancer cells and block cell replication via conjugated DNA intercalating quinoxaline moiety. In vitro cell screening showed that dT-QX selectively kills a variety of cancer cells including liver carcinoma, breast adenocarcinoma and brain glioma cells; whereas it had a low cytotoxicity in normal cells such as …