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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Functional Role Of The N-Terminal Domain In Connexin 46/50 By In Silico Mutagenesis And Molecular Dynamics Simulation, Umair Khan Jun 2021

Functional Role Of The N-Terminal Domain In Connexin 46/50 By In Silico Mutagenesis And Molecular Dynamics Simulation, Umair Khan

University Honors Theses

Connexins form intercellular channels known as gap junctions that facilitate diverse physiological roles, from long-range electrical and chemical coupling to nutrient exchange. Recent structural studies on Cx46 and Cx50 have defined a novel and stable open state and implicated the amino-terminal (NT) domain as a major contributor to functional differences between connexin isoforms. This thesis presents two studies which use molecular dynamics simulations with these new structures to provide mechanistic insight into the function and behavior of the NTH in Cx46 and Cx50. In the first, residues in the NTH that differ between Cx46 and Cx50 are swapped between the …


Urban Air Quality Modeling: Evaluating Impacts Of Ecoroofs On Urban Air Quality In Portland, Oregon, Danlyn L. Brennan, Selina Teng Aug 2020

Urban Air Quality Modeling: Evaluating Impacts Of Ecoroofs On Urban Air Quality In Portland, Oregon, Danlyn L. Brennan, Selina Teng

altREU Projects

In this work, the authors present a mathematical model simulating the impact of ecoroof vegetation on air quality in an urban microclimate. An ecoroof is a layer of vegetation established on rooftops to reduce stormwater runoff, mitigate heat, and enhance air quality. Certain plant species in ecoroofs may however have a detrimental effect on air quality, due to their emission of biogenic volatile organic compounds (BVOCs), which include potentially reactive species such as isoprene. These chemical species can interact with urban air pollution, particularly NOx produced by car traffic, to create other harmful pollutants such as ozone and particulate matter …


Archaeosine Modification Of Archaeal Trna - A Role In Structural Stabilization, Ben Turner, Brett W. Burkhart, Katrin Weidenbach, Robert Ross, Patrick A. Limbach, Ruth A. Schmitz, Valérie De Crécy-Lagard, Kenneth M. Stedman, Thomas J. Santangelo, Dirk Iwata-Reuyl Jan 2020

Archaeosine Modification Of Archaeal Trna - A Role In Structural Stabilization, Ben Turner, Brett W. Burkhart, Katrin Weidenbach, Robert Ross, Patrick A. Limbach, Ruth A. Schmitz, Valérie De Crécy-Lagard, Kenneth M. Stedman, Thomas J. Santangelo, Dirk Iwata-Reuyl

Biology Faculty Publications and Presentations

Archaeosine (G+) is a structurally complex modified nucleoside found quasi-universally in the tRNA of Archaea and located at position 15 in the dihydrouridine loop, a site not modified in any tRNA outside of the Archaea. G+ is characterized by an unusual 7-deazaguanosine core structure with a formamidine group at the 7-position. The location of G+ at position 15, coupled with its novel molecular structure, led to a hypothesis that G+ stabilizes tRNA tertiary structure through several distinct mechanisms. To test whether G+ contributes to tRNA stability and define the biological role of G+, we investigated the consequences of introducing targeted …


Structural Dynamics Of A Mitochondrial Trna Possessing Weak Thermodynamic Stability, Hari Bhaskaran, Takaaki Taniguchi, Takeo Suzuki, Tsutomu Suzuki, John J. Perona Feb 2014

Structural Dynamics Of A Mitochondrial Trna Possessing Weak Thermodynamic Stability, Hari Bhaskaran, Takaaki Taniguchi, Takeo Suzuki, Tsutomu Suzuki, John J. Perona

Chemistry Faculty Publications and Presentations

Folding dynamics are ubiquitously involved in controlling the multivariate functions of RNAs. While the high thermodynamic stabilities of some RNAs favor purely native states at equilibrium, it is unclear whether weakly stable RNAs exist in random, partially folded states or sample well-defined, globally folded conformations. Using a folding assay that precisely tracks the formation of native aminoacylable tRNA, we show that the folding of a weakly stable human mitochondrial (hmt) leucine tRNA is hierarchical with a distinct kinetic folding intermediate. The stabilities of the native and intermediate conformers are separated by only about 1.2 kcal/mol, and the species are readily …


Intrinsic Disorder Within An Akap-Protein Kinase A Complex Guides Local Substrate Phosphorylation, F. Donelson Smith, Steve L. Reichow, Jessica L. Esseltine, Dan Shi, Lorene K. Langeberg, John D. Scott, Tamir Gonen Nov 2013

Intrinsic Disorder Within An Akap-Protein Kinase A Complex Guides Local Substrate Phosphorylation, F. Donelson Smith, Steve L. Reichow, Jessica L. Esseltine, Dan Shi, Lorene K. Langeberg, John D. Scott, Tamir Gonen

Chemistry Faculty Publications and Presentations

Anchoring proteins sequester kinases with their substrates to locally disseminate intracellular signals and avert indiscriminate transmission of these responses throughout the cell. Mechanistic understanding of this process is hampered by limited structural information on these macromolecular complexes. A-kinase anchoring proteins (AKAPs) spatially constrain phosphorylation by cAMP-dependent protein kinases (PKA). Electron microscopy and three-dimensional reconstructions of type-II PKA-AKAP18γ complexes reveal hetero-pentameric assemblies that adopt a range of flexible tripartite configurations. Intrinsically disordered regions within each PKA regulatory subunit impart the molecular plasticity that affords an ∼16 nanometer radius of motion to the associated catalytic subunits. Manipulating flexibility within the PKA holoenzyme …


Allosteric Mechanism Of Water Channel Gating By Ca2+–Calmodulin, Steve Reichow, Daniel M. Clemens, J. Alfredo Freites, Karin L. Németh-Cahalan, Matthias Heyden, Douglas J. Tobias, James E. Hall, Tamir Gonen Sep 2013

Allosteric Mechanism Of Water Channel Gating By Ca2+–Calmodulin, Steve Reichow, Daniel M. Clemens, J. Alfredo Freites, Karin L. Németh-Cahalan, Matthias Heyden, Douglas J. Tobias, James E. Hall, Tamir Gonen

Chemistry Faculty Publications and Presentations

Calmodulin (CaM) is a universal regulatory protein that communicates the presence of calcium to its molecular targets and correspondingly modulates their function. This key signaling protein is important for controlling the activity of hundreds of membrane channels and transporters. However, our understanding of the structural mechanisms driving CaM regulation of full-length membrane proteins has remained elusive. In this study, we determined the pseudo-atomic structure of full-length mammalian aquaporin-0 (AQP0, Bos Taurus) in complex with CaM using electron microscopy to understand how this signaling protein modulates water channel function. Molecular dynamics and functional mutation studies reveal how CaM binding inhibits AQP0 …


Akap2 Anchors Pka With Aquaporin-0 To Support Ocular Lens Transparency, Matthew G. Gold, Steve Reichow, Susan E. O'Neill, Chad R. Weisbrod, Lorene K. Langeberg, James E. Bruce, Tamir Gonen, John D. Scott Oct 2011

Akap2 Anchors Pka With Aquaporin-0 To Support Ocular Lens Transparency, Matthew G. Gold, Steve Reichow, Susan E. O'Neill, Chad R. Weisbrod, Lorene K. Langeberg, James E. Bruce, Tamir Gonen, John D. Scott

Chemistry Faculty Publications and Presentations

A decline in ocular lens transparency known as cataract afflicts 90% of individuals by the age 70. Chronic deterioration of lens tissue occurs as a pathophysiological consequence of defective water and nutrient circulation through channel and transporter proteins. A key component is the aquaporin-0 (AQP0) water channel whose permeability is tightly regulated in healthy lenses. Using a variety of cellular and biochemical approaches we have discovered that products of the A-kinase anchoring protein 2 gene (AKAP2/AKAP-KL) form a stable complex with AQP0 to sequester protein kinase A (PKA) with the channel. This permits PKA phosphorylation of serine 235 within a …


Advances In Structural And Functional Analysis Of Membrane Proteins By Electron Crystallography, Goragot Wisedchaisri, Steve Reichow, Tamir Gonen Oct 2011

Advances In Structural And Functional Analysis Of Membrane Proteins By Electron Crystallography, Goragot Wisedchaisri, Steve Reichow, Tamir Gonen

Chemistry Faculty Publications and Presentations

Electron crystallography is a powerful technique for the study of membrane protein structure and function in the lipid environment. When well-ordered two-dimensional crystals are obtained the structure of both protein and lipid can be determined and lipid-protein interactions analyzed. Protons and ionic charges can be visualized by electron crystallography and the protein of interest can be captured for structural analysis in a variety of physiologically distinct states. This review highlights the strengths of electron crystallography and the momentum that is building up in automation and the development of high throughput tools and methods for structural and functional analysis of membrane …