Other Biochemistry, Biophysics, and Structural Biology Commons^™

Growth And Transport Properties Of Complementary Germanium Nanowire Field Effect Transistors, Andrew B. Greytak, Lincoln J. Lauhon, Mark S. Gudiksen, Charles M. Lieber

Faculty Publications

n- and p-type Ge nanowires were synthesized by a multistep process in which axial elongation, via vapor–liquid–solid (VLS) growth, and doping were accomplished in separate chemical vapor deposition steps. Intrinsic, single-crystal, Ge nanowires prepared by Au nanocluster-mediated VLS growth were surface-doped in situ using diborane or phosphine, and then radial growth of an epitaxial Ge shell was used to cap the dopant layer. Field-effect transistors prepared from these Ge nanowires exhibited on currents and transconductances up to 850 µA/µm and 4.9 µA/V, respectively, with device yields of >85%.

Photoreactive Bicyclic Amino Acids As Substrates For Mutant Escherichia Coli Phenylalanyl-Trna Synthetases, Thomas Bentin, Ramin Hamzavi, Jahan Salomonsson, Hervé Roy, Michael Ibba, Peter E. Nielsen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Unnatural amino acids carrying reactive groups that can be selectively activated under non-invasive biologically benign conditions are of interest in protein engineering as biological tools for the analysis of protein-protein and protein-nucleic acids interactions. The double ring system phenylalanine analogues benzofuranylalanine and benzotriazolylalanine were synthesized, and their photolability was tested by UV irradiation at 254, 320, and 365 nm. Although both showed photo reactivity, benzofuranylalanine appeared as the most promising compound because this amino acid was activated by UVA (long wavelength) irradiation. These amino acids were also tested for in vitro charging of tRNA^Phe and for protein mutagenesis via …

Differences In Response To Hypoxia In The Three-Spined Stickleback From Lotic And Lentic Localities: Dominance And An Anaerobic Metabolite, L. U. Sneddon, J. Yerbury

Aquaculture Collection

Dominance hierarchies of the three-spined stickleback Gasterosteus aculeatus from river and pond populations were subjected to hypoxia (20%, range±1%). Under hypoxia, the hierarchies were less stable in terms of rank position and tissue L-lactate was higher in river fish than pond fish under normoxia and hypoxia. Dominant fish gained mass under normoxia but lost mass under hypoxic conditions possibly due to them maintaining high levels of aggression.

The Identity Of Proteins Associated With A Small Heat Shock Protein During Heat Stress In Vivo Indicates That These Chaperones Protect A Wide Range Of Cellular Functions, Eman Basha, Garrett J. Lee, Linda A. Breci, Andrew C. Hausrath, Nicole R. Buan, Kim C. Giese, Elizabeth Vierling

Department of Biochemistry: Faculty Publications

The small heat shock proteins (sHSPs) are a ubiquitous class of ATP-independent chaperones believed to prevent irreversible protein aggregation and to facilitate subsequent protein renaturation in cooperation with ATP-dependent chaperones. Although sHSP chaperone activity has been studied extensively in vitro, understanding the mechanism of sHSP function requires identification of proteins that are sHSP substrates in vivo. We have used both immunoprecipitation and affinity chromatography to recover 42 proteins that specifically interact with Synechocystis Hsp16.6 in vivo during heat treatment. These proteins can all be released from Hsp16.6 by the ATP-dependent activity of DnaK and cochaperones and are heat-labile. Thirteen …

Divergence In Non-Cognate Amino Acid Recognition Between Class I And Class Ii Lysyl-Trna Synthetases, Jeffrey D. Levengood, Sandro F. Ataide, Hervé Roy, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Lysine insertion during coded protein synthesis requires lysyl-tRNA^Lys, which is synthesized by lysyl-tRNA synthetase (LysRS). Two unrelated forms of LysRS are known: LysRS2, which is found in eukaryotes, most bacteria, and a few archaea, and LysRS1, which is found in most archaea and a few bacteria. To compare amino acid recognition between the two forms of LysRS, the effects of l-lysine analogues on aminoacylation were investigated. Both enzymes showed stereospecificity toward the l-enantiomer of lysine and discriminated against noncognate amino acids with different R-groups (arginine, ornithine). Lysine analogues containing substitutions at other positions were generally most effective as …

5-Hydroxydecanoate Is Metabolised In Mitochondria And Creates A Rate-Limiting Bottleneck For Β-Oxidation Of Fatty Acids, Peter J. Hanley, Stefan Dröse, Ulrich Brandt, Rachel A. Lareau, Abir L. Banerjee, D. K. Srivastava, Leonard J. Banaszak, Joseph J. Barycki, Paul P. Van Veldhoven, Jürgen Daut

Department of Biochemistry: Faculty Publications

5-Hydroxydecanoate (5-HD) blocks pharmacological and ischaemic preconditioning, and

has been postulated to be a specific inhibitor of mitochondrial ATP-sensitive K+ (KATP)

channels. However, recent work has shown that 5-HD is activated to 5-hydroxydecanoyl-CoA

(5-HD-CoA), which is a substrate for the first step of β-oxidation. We have now

analysed the complete β-oxidation of 5-HD-CoA using specially synthesised (and purified)

substrates and enzymes, as well as isolated rat liver and heart mitochondria, and compared

it with the metabolism of the physiological substrate decanoyl-CoA. At the second step of

β-oxidation, catalysed by enoyl-CoA hydratase, enzyme kinetics were …

Interactions Between Small Heat Shock Protein Subunits And Substrate In Small Heat Shock Protein-Substrate Complexes, Kenneth L. Friedrich, Kim C. Giese, Nicole R. Baun, Elizabeth Vierling

Department of Biochemistry: Faculty Publications

Small heat shock proteins (sHSPs) are dynamic oligomeric

proteins that bind unfolding proteins and protect

them from irreversible aggregation. This binding results

in the formation of sHSP-substrate complexes from

which substrate can later be refolded. Interactions between

sHSP and substrate in sHSP-substrate complexes

and the mechanism by which substrate is transferred to

ATP-dependent chaperones for refolding are poorly defined.

We have established C-terminal affinity-tagged

sHSPs from a eukaryote (pea HSP18.1) and a prokaryote

(Synechocystis HSP16.6) as tools to investigate these issues.

We demonstrate that sHSP subunit exchange for

HSP18.1 and HSP16.6 is temperature-dependent and

rapid at the optimal growth …

Interactions Between Small Heat Shock Protein Subunits And Substrate In Small Heat Shock Protein-Substrate Complexes, Kenneth L. Friedrich,, Kim C. Giese, Nicole R. Buan, Elizabeth Vierling

Department of Biochemistry: Faculty Publications

Small heat shock proteins (sHSPs) are dynamic oligomeric proteins that bind unfolding proteins and protect them from irreversible aggregation. This binding results in the formation of sHSP-substrate complexes from which substrate can later be refolded. Interactions between sHSP and substrate in sHSP-substrate complexes and the mechanism by which substrate is transferred to ATP-dependent chaperones for refolding are poorly defined. We have established C-terminal affinity-tagged sHSPs from a eukaryote (pea HSP18.1) and a prokaryote (Synechocystis HSP16.6) as tools to investigate these issues. We demonstrate that sHSP subunit exchange for HSP18.1 and HSP16.6 is temperature-dependent and rapid at the optimal growth temperature …

Altered Phosphorylation Of [Beta]-Catenin In Glucocorticoid Treated 235-1 Rat Pituitary Tumor Cells, Susie K. Saunders

Theses, Dissertations and Capstones

Beta-catenin is an essential cell adhesion and signaling protein, associated with high prolactin levels in rat pituitary tumor cells. It has been shown that phosphorylation affects the location and activity of b-catenin. Glycogen synthase kinase (GSK3-b) is a serine-threonine kinase that phosphorylates b-catenin on N-terminal residues, targeting it for proteasomal degradation. Studies have shown that C-terminal tyrosine phosphorylation decreases the association of b-catenin with cadherin. In 235-1 rat pituitary tumor cells, our lab has shown that the glucocorticoid analog dexamethasone (Dex) decreases the half- life of b-catenin while increasing the activity of GSK3-b. The current study was undertaken to examine …

Mobilization Of Intracellular Copper Stores By The Ctr2 Vacuolar Copper Transporter, Erin M. Rees, Jaekwon Lee, Dennis J. Thiele

Department of Biochemistry: Faculty Publications

Copper plays an essential role in processes including signaling to the transcription and protein trafficking machinery, oxidative phosphorylation, iron mobilization, neuropeptide maturation, and normal development. Whereas much is known about intracellular mobilization of ions such as calcium, little information is available on how eukaryotic cells mobilize intracellular copper stores. We describe a mechanism by which the Saccharomyces cerevisiae Ctr2 protein provides bioavailable copper via mobilization of intracellular copper stores. Whereas Ctr2 exhibits structural similarity to the Ctr1 plasma membrane copper importer, microscopic and biochemical fractionation studies localize Ctr2 to the vacuole membrane. We demonstrate that Ctr2 mobilizes vacuolar copper stores …

The Identity Of Proteins Associated With A Small Heat Shock Protein During Heat Stress In Vivo Indicates That These Chaperones Protect A Wide Range Of Cellular Functions, Eman Basha, Garrett J. Lee, Linda A. Breci, Andrew C. Hausrath, Nicole R. Baun, Kim C. Giese, Elizabeth Vierling

Department of Biochemistry: Faculty Publications

The small heat shock proteins (sHSPs) are a ubiquitous

class of ATP-independent chaperones believed to

prevent irreversible protein aggregation and to facilitate

subsequent protein renaturation in cooperation

with ATP-dependent chaperones. Although sHSP chaperone

activity has been studied extensively in vitro, understanding

the mechanism of sHSP function requires

identification of proteins that are sHSP substrates in

vivo. We have used both immunoprecipitation and affinity

chromatography to recover 42 proteins that specifically

interact with Synechocystis Hsp16.6 in vivo during

heat treatment. These proteins can all be released from

Hsp16.6 by the ATP-dependent activity of DnaK and cochaperones

and are heat-labile. …

Aminoacyl-Trnas: Setting The Limits Of The Genetic Code, Michael Ibba, Dieter Söll

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNAs (aa-tRNAs) are simple molecules with a single purpose—to serve as substrates for translation. They consist of mature tRNAs to which an amino acid has been esterified at the 3′-end. The 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases (aaRSs, of which there are two classes), one for each amino acid of the genetic code (Ibba and Söll 2000). This would be fine if it were not for the fact that such a straightforward textbook scenario is not true in a single known living organism. aa-tRNAs lie at the heart of gene expression; they interpret …