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Full-Text Articles in Molecular Biology

Biosynthetic Mechanism Of The Antibiotic Capuramycin, Erfu Yan Jan 2018

Biosynthetic Mechanism Of The Antibiotic Capuramycin, Erfu Yan

Theses and Dissertations--Pharmacy

A-102395 is a member of the capuramycin family of antibiotics which was isolated from the culture broth of Amycolatopsis sp. SANK 60206. A-102339 is structurally classified as a nucleoside antibiotic, which like all members of the capuramycin family, inhibits bacterial MraY (translocase I) with IC50 of 11 nM which is the lowest among the capuramycin family. A semisynthetic derivative of capuramycin is currently in clinical trials as an antituberculosis antibiotic, suggesting high potential for using A-102395 as a starting point for new antibiotic discovery. In contrast to other capuramycins, A-102395 has a unique arylamine-containing polyamide side chain. The biosynthetic ...


Investigation Of The Mechanism Of Action For Mithramycin And The Biosynthesis Of L-Rednose In Saquayamycins, Stevi Weidenbach Jan 2017

Investigation Of The Mechanism Of Action For Mithramycin And The Biosynthesis Of L-Rednose In Saquayamycins, Stevi Weidenbach

Theses and Dissertations--Pharmacy

Natural products continue to be a major chemical lead matter for drug discovery due to their diverse chemical structures and bioactivities. Clinically significant natural products include anti-cancer and anti-infective compounds and while many more of these compounds show promising bioactivity, their clinical relevance is often limited by toxicity or poor solubility. Combinatorial biosynthesis can be employed to modify existing chemical scaffolds towards reducing these limitations. To fully take advantage of these biochemical tools, it is important to understand the biosynthesis and mechanism of action of the molecules.

Saccharides in glycosylated natural products provide specific interactions with cellular targets and are ...


Towards Elucidation Of The Mechanism Of Biological Nanomotors, Zhengyi Zhao Jan 2016

Towards Elucidation Of The Mechanism Of Biological Nanomotors, Zhengyi Zhao

Theses and Dissertations--Pharmacy

Biological functions such as cell mitosis, bacterial binary fission, DNA replication or repair, homologous recombination, Holliday junction resolution, viral genome packaging, and cell entry all involve biomotor-driven DNA translocation. In the past, the ubiquitous biological nanomotors were classified into two categories: linear and rotation motors. In 2013, we discovered a third type of biomotor, revolving motor without rotation. The revolving motion is further found to be widespread among many biological systems. In addition, the detailed sequential action mechanism of the ATPase ring in the phi29 dsDNA packaging motor has been elucidated: ATP binding induces a conformational entropy alternation of ATPase ...


Elucidating Proteasome Catalytic Subunit Composition And Its Role In Proteasome Inhibitor Resistance, Kimberly C. Carmony Jan 2016

Elucidating Proteasome Catalytic Subunit Composition And Its Role In Proteasome Inhibitor Resistance, Kimberly C. Carmony

Theses and Dissertations--Pharmacy

Proteasome inhibitors bortezomib and carfilzomib are FDA-approved anticancer agents that have contributed to significant improvements in treatment outcomes. However, the eventual onset of acquired resistance continues to limit their clinical utility, yet a clear consensus regarding the underlying mechanisms has not been reached.

Bortezomib and carfilzomib are known to target both the constitutive proteasome and the immunoproteasome, two conventional proteasome subtypes comprising distinctive sets of catalytic subunits. While it has become increasingly evident that additional, ‘intermediate’ proteasome subtypes, which harbor non-standard mixtures of constitutive proteasome and immunoproteasome catalytic subunits, represent a considerable proportion of the proteasome population in many cell ...


Chemoenzymatic Studies To Enhance The Chemical Space Of Natural Products, Jhong-Min Chen Jan 2015

Chemoenzymatic Studies To Enhance The Chemical Space Of Natural Products, Jhong-Min Chen

Theses and Dissertations--Pharmacy

Natural products provide some of the most potent anticancer agents and offer a template for new drug design or improvement with the advantage of an enormous chemical space. The overall goal of this thesis research is to enhance the chemical space of two natural products in order to generate novel drugs with better in vivo bioactivities than the original natural products.

Polycarcin V (PV) is a gilvocarcin-type antitumor agent with similar structure and comparable bioactivity with the principle compound of this group, gilvocarcin V (GV). Modest modifications of the polyketide-derived tetracyclic core of GV had been accomplished, but the most ...


Amalgamation Of Nucleosides And Amino Acids In Antibiotic Biosynthesis, Sandra H. Barnard Jan 2013

Amalgamation Of Nucleosides And Amino Acids In Antibiotic Biosynthesis, Sandra H. Barnard

Theses and Dissertations--Pharmacy

The rapid increase in antibiotic resistance demands the identification of novel antibiotics with novel targets. One potential antibacterial target is the biosynthesis of peptidoglycan cell wall, which is both ubiquitous and necessary for bacterial survival. Both the caprazamycin-related compounds A-90289 and muraminomicin, as well as the capuramycin-related compounds A-503083 and A-102395 are potent inhibitors of the translocase I enzyme, one of the key enzymes required for cell wall biosynthesis. The caprazamycin-related compounds contain a core nonproteinogen b-hydroxy-a-amino acid referred to as 5’-C-glycyluridine (GlyU). Residing within the biosynthetic gene clusters of the aforementioned compounds is a shared open reading ...


Expression Of Rna Nanoparticles Based On Bacteriophage Phi29 Prna In Escherichia Coli And Bacillus Subtilis, Le Zhang Jan 2013

Expression Of Rna Nanoparticles Based On Bacteriophage Phi29 Prna In Escherichia Coli And Bacillus Subtilis, Le Zhang

Theses and Dissertations--Pharmacy

Currently, most of the RNAs used in lab research are prepared by in vitro transcription or chemical synthesis, which can be costly. In vivo expression in bacterial cells is another approach to RNA preparation that allows large scale production at a lower cost. However, there are some obstacles in bacterial expression, including RNA degradation in host cell, as well as RNA extraction and purification. tRNA and 5S RNA have been reported as scaffolds to circumvent the degradation problem. These scaffolds can not only make the RNA product survive in the cell but also increase the stability after extraction.

The packaging ...


Role Of Cyclooxygenase-2 In Abdominal Aortic Aneurysms In Mice, Kamalika Mukherjee Jan 2012

Role Of Cyclooxygenase-2 In Abdominal Aortic Aneurysms In Mice, Kamalika Mukherjee

Theses and Dissertations--Pharmacy

Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease with no available pharmacological treatment. AAA formation reduces the structural integrity of the vessel and increases the susceptibility to rupture. The inflammatory response within human aneurysmal tissue is characterized by increased expression of cyclooxygenase-2 (COX-2). Similarly, in a mouse model of the disease induced by chronic Angiotensin II (AngII) infusion, we have shown that COX-2 expression in the abdominal aortic smooth muscle layer increases early in the development of the disease. Furthermore, genetic or pharmacological inactivation of COX-2 prior to disease initiation reduces AAA incidence.

The current study utilized nonhyperlipidemic mice ...