Pharmacy and Pharmaceutical Sciences Commons^™

Amphiphilic Tobramycin Analogues As Antibacterial And Antifungal Agents, Sanjib K. Shrestha, Marina Y. Fosso, Keith D. Green, Sylvie Garneau-Tsodikova

Pharmaceutical Sciences Faculty Publications

In this study, we investigated the in vitro antifungal activities, cytotoxicities, and membrane-disruptive actions of amphiphilic tobramycin (TOB) analogues. The antifungal activities were established by determination of MIC values and in time-kill studies. Cytotoxicity was evaluated in mammalian cell lines. The fungal membrane-disruptive action of these analogues was studied by using the membrane-impermeable dye propidium iodide. TOB analogues bearing a linear alkyl chain at their 6″-position in a thioether linkage exhibited chain length-dependent antifungal activities. Analogues with C₁₂ and C₁₄ chains showed promising antifungal activities against tested fungal strains, with MIC values ranging from 1.95 to 62.5 mg/liter …

Crystal Structure Of O-Methyltransferase Calo6 From The Calicheamicin Biosynthetic Pathway: A Case Of Challenging Structure Determination At Low Resolution, Oleg V. Tsodikov, Caixia Hou, Christopher T. Walsh, Sylvie Garneau-Tsodikova

Pharmaceutical Sciences Faculty Publications

BACKGROUND: Calicheamicins (CAL) are enedyine natural products with potent antibiotic and cytotoxic activity, used in anticancer therapy. The O-methyltransferase CalO6 is proposed to catalyze methylation of the hydroxyl moiety at the C2 position of the orsellinic acid group of CAL.

RESULTS: Crystals of CalO6 diffracted non-isotropically, with the usable data extending to 3.4 Å. While no single method of crystal structure determination yielded a structure of CalO6, we were able to determine its structure by using molecular replacement-guided single wavelength anomalous dispersion by using diffraction data from native crystals of CalO6 and a highly non-isomorphous mercury derivative. The structure …

The Biosynthesis Of Capuramycin-Type Antibiotics: Identification Of The A-102395 Biosynthetic Gene Cluster, Mechanism Of Self-Resistence, And Formation Of Uridine-5'-Carboxamide, Wenlong Cai, Anwesha Goswami, Zhaoyong Yang, Xiaodong Liu, Keith D. Green, Sandra Barnard-Britson, Satoshi Baba, Masanori Funabashi, Koichi Nonaka, Manjula Sunkara, Andrew J. Morris, Anatol P. Spork, Christian Ducho, Sylvie Garneau-Tsodikova, Jon S. Thorson, Steven Van Lanen

Pharmaceutical Sciences Faculty Publications

A-500359s, A-503083s, and A-102395 are capuramycin-type nucleoside antibiotics that were discovered using a screen to identify inhibitors of bacterial translocase I, an essential enzyme in peptidoglycan cell wall biosynthesis. Like the parent capuramycin, A-500359s and A-503083s consist of three structural components: a uridine-5'-carboxamide (CarU), a rare unsaturated hexuronic acid, and an aminocaprolactam, the last of which is substituted by an unusual arylamine-containing polyamide in A-102395. The biosynthetic gene clusters for A-500359s and A-503083s have been reported, and two genes encoding a putative non-heme Fe(II)-dependent α-ketoglutarate:UMP dioxygenase and an l-Thr:uridine-5'-aldehyde transaldolase were uncovered, suggesting that C-C bond formation during assembly of …