Molecular Biology Commons^™

An Arginine Finger Regulates The Sequential Action Of Asymmetrical Hexameric Atpase In The Double-Stranded Dna Translocation Motor, Zhengyi Zhao, Gian Marco De-Donatis, Chad T. Schwartz, Huaming Fang, Jingyuan Li, Peixuan Guo

Pharmaceutical Sciences Faculty Publications

Biological motors are ubiquitous in living systems. Currently, how the motor components coordinate the unidirectional motion is elusive in most cases. Here, we report that the sequential action of the ATPase ring in the DNA packaging motor of bacteriophage ϕ29 is regulated by an arginine finger that extends from one ATPase subunit to the adjacent unit to promote noncovalent dimer formation. Mutation of the arginine finger resulted in the interruption of ATPase oligomerization, ATP binding/hydrolysis, and DNA translocation. Dimer formation reappeared when arginine mutants were mixed with other ATPase subunits that can offer the arginine to promote their interaction. Ultracentrifugation …

Biological Nanomotors With A Revolution, Linear, Or Rotation Motion Mechanism, Peixuan Guo, Hiroyuki Noji, Christopher M. Yengo, Zhengyi Zhao, Ian Grainge

Nanobiotechnology Center Faculty Publications

The ubiquitous biological nanomotors were classified into two categories in the past: linear and rotation motors. In 2013, a third type of biomotor, revolution without rotation (http://rnanano.osu.edu/movie.html), was discovered and found to be widespread among bacteria, eukaryotic viruses, and double-stranded DNA (dsDNA) bacteriophages. This review focuses on recent findings about various aspects of motors, including chirality, stoichiometry, channel size, entropy, conformational change, and energy usage rate, in a variety of well-studied motors, including F_oF₁ ATPase, helicases, viral dsDNA-packaging motors, bacterial chromosome translocases, myosin, kinesin, and dynein. In particular, dsDNA translocases are used to illustrate how …

Structures Of Eccb1 And Eccd1 From The Core Complex Of The Mycobacterial Esx-1 Type Vii Secretion System, Jonathan Mark Wagner, Sum Chan, Timothy J. Evans, Sara Kahng, Jennifer Kim, Mark A. Arbing, David Eisenberg, Konstantin V. Korotkov

Molecular and Cellular Biochemistry Faculty Publications

Background: The ESX-1 type VII secretion system is an important determinant of virulence in pathogenic mycobacteria, including Mycobacterium tuberculosis. This complicated molecular machine secretes folded proteins through the mycobacterial cell envelope to subvert the host immune response. Despite its important role in disease very little is known about the molecular architecture of the ESX-1 secretion system.

Results: This study characterizes the structures of the soluble domains of two conserved core ESX-1 components – EccB₁ and EccD₁. The periplasmic domain of EccB₁ consists of 4 repeat domains and a central domain, which together form a quasi …

Analogous Cellular Contribution And Healing Mechanisms Following Digit Amputation And Phalangeal Fracture In Mice, Lindsay A. Dawson, Jennifer Simkin, Michelle Sauque, Maegan Pela, Teresa Palkowski, Ken Muneoka

Biology Faculty Publications

Regeneration of amputated structures is severely limited in humans and mice, with complete regeneration restricted to the distal portion of the terminal phalanx (P3). Here, we investigate the dynamic tissue repair response of the second phalangeal element (P2) post amputation in the adult mouse, and show that the repair response of the amputated bone is similar to the proximal P2 bone fragment in fracture healing. The regeneration-incompetent P2 amputation response is characterized by periosteal endochondral ossification resulting in the deposition of new trabecular bone, corresponding to a significant increase in bone volume; however, this response is not associated with bone …

Functional Roles For Post-Translational Modifications Of T-Snares In Platelets, Jinchao Zhang

Theses and Dissertations--Molecular and Cellular Biochemistry

Platelets affect vascular integrity by secreting a host of molecules that promote hemostasis and its sequela. Given its importance, it is critical to understand how platelet exocytosis is controlled. Post-translational modifications, such as phosphorylation and acylation, have been shown to affect signaling pathways and platelet function. In this dissertation, I focus on how these modifications affect the t-SNARE proteins, SNAP-23 and syntaxin-11, which are both required for platelet secretion. SNAP-23 is regulated by phosphorylation. Using a proteoliposome fusion assay, I demonstrate that purified IκB Kinase (IKK) phosphorylated SNAP-23, which increased the initial rates of SNARE-mediated liposome fusion. SNAP-23 mutants …

It Is All About (U)Biquitin: Role Of Altered Ubiquitin-Proteasome System And Uchl1 In Alzheimer Disease, Antonella Tramutola, Fabio Di Domenico, Eugenio Barone, Marzia Perluigi, D. Allan Butterfield

Chemistry Faculty Publications

Free radical-mediated damage to macromolecules and the resulting oxidative modification of different cellular components are a common feature of aging, and this process becomes much more pronounced in age-associated pathologies, including Alzheimer disease (AD). In particular, proteins are particularly sensitive to oxidative stress-induced damage and these irreversible modifications lead to the alteration of protein structure and function. In order to maintain cell homeostasis, these oxidized/damaged proteins have to be removed in order to prevent their toxic accumulation. It is generally accepted that the age-related accumulation of “aberrant” proteins results from both the increased occurrence of damage and the decreased efficiency …

Integrin Α6Β4 Promotes Pancreatic Cancer Invasion By Altering Dna Repair-Mediated Epigenetics, Brittany L. Carpenter

Theses and Dissertations--Molecular and Cellular Biochemistry

Integrin α6β4 is upregulated in pancreatic carcinoma, where signaling promotes metastatic properties, in part by altering the transcriptome. Such alterations can be accomplished through DNA demethylation of specific promoters, as seen with the pro-metastatic gene S100A4. I found that signaling from integrin α6β4 dramatically upregulates expression of amphiregulin (AREG) and epiregulin (EREG), ligands for the epidermal growth factor receptor (EGFR), and that these ligands promote pancreatic carcinoma invasion. To determine if AREG and EREG are regulated by DNA methylation, pancreatic cancer cells with low AREG and EREG expression were treated with the DNA methyltransferase inhibitor 5-aza-2’-deoxycytidine (5-Aza-CdR), resulting in stable …

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 …

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 …

Molecular And Biochemical Signaling Underlying Arabidopsis-Bacterial/Virus/Fungal Interactions, Mohamed H. El-Shetehy

Theses and Dissertations--Plant Pathology

Systemic acquired resistance (SAR) is a form of inducible defense response triggered upon localized infection that confers broad-spectrum disease resistance against secondary infections. Several factors are known to regulate SAR and these include phenolic phytohormone salicylic acid (SA), phosphorylated sugar glycerol-3-phosphate (G3P), and dicarboxylic acid azelaic acid (AzA). This study evaluated a role for free radicals nitric oxide (NO) and reactive oxygen species (ROS) in SAR. Normal accumulation of both NO and ROS was required for normal SAR and mutations preventing NO/ROS accumulation and/or biosynthesis compromised SAR. A role for NO and ROS was further established using pharmacological approaches. Notably, …