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Full-Text Articles in Life Sciences

Functional Association Between Three Archaeal Aminoacyl-Trna Synthetases, Mette Praetorius-Ibba, Corinne D. Hausmann, Molly Paras, Theresa E. Rogers, Michael Ibba Dec 2006

Functional Association Between Three Archaeal Aminoacyl-Trna Synthetases, Mette Praetorius-Ibba, Corinne D. Hausmann, Molly Paras, Theresa E. Rogers, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetases (aaRSs) are responsible for attaching amino acids to their cognate tRNAs during protein synthesis. In eukaryotes aaRSs are commonly found in multi-enzyme complexes, although the role of these complexes is still not completely clear. Associations between aaRSs have also been reported in archaea, including a complex between prolyl-(ProRS) and leucyl-tRNA synthetases (LeuRS) in Methanothermobacter thermautotrophicus that enhances tRNAPro aminoacylation. Yeast two-hybrid screens suggested that lysyl-tRNA synthetase (LysRS) also associates with LeuRS in M. thermautotrophicus. Co-purification experiments confirmed that LeuRS, LysRS, and ProRS associate in cell-free extracts. LeuRS bound LysRS and ProRS with a comparable KD …


Aspartyl-Trna Synthetase Is The Target Of Peptidenucleotide Antibiotic Microcin C, Anastasia Metlitskaya, Teymur Kazakov, Aigar Kommer, Olga Pavlova, Mette Praetorius-Ibba, Michael Ibba, Igor Krasheninnkov, Vyacheslav Kolb, Inessa Khmel, Konstantin Severinov Mar 2006

Aspartyl-Trna Synthetase Is The Target Of Peptidenucleotide Antibiotic Microcin C, Anastasia Metlitskaya, Teymur Kazakov, Aigar Kommer, Olga Pavlova, Mette Praetorius-Ibba, Michael Ibba, Igor Krasheninnkov, Vyacheslav Kolb, Inessa Khmel, Konstantin Severinov

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Microcin C is a ribosome-synthesized heptapeptide that contains a modified adenosine monophosphate covalently attached to the C-terminal aspartate. Microcin C is a potent inhibitor of bacterial cell growth. Based on the in vivo kinetics of inhibition of macromolecular synthesis, Microcin C targets translation, through a mechanism that remained undefined. Here, we show that Microcin C is a subject of specific degradation inside the sensitive cell. The product of degradation, a modified aspartyl-adenylate containing an N-acylphosphoramidate linkage, strongly inhibits translation by blocking the function of aspartyl-tRNA synthetase.


C To U Editing Stimulates A To I Editing In The Anticodon Loop Of A Cytoplasmic Threonyl Trna In Trypanosoma Brucei, Mary Anne T. Rubio, Frank L. Ragone, Kirk W. Gaston, Michael Ibba, Juan D. Alfonzo Jan 2006

C To U Editing Stimulates A To I Editing In The Anticodon Loop Of A Cytoplasmic Threonyl Trna In Trypanosoma Brucei, Mary Anne T. Rubio, Frank L. Ragone, Kirk W. Gaston, Michael Ibba, Juan D. Alfonzo

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Editing of tRNAs is widespread in nature and either changes the decoding properties or restores the folding of a tRNA. Unlike the phylogenetically disperse adenosine (A) to inosine (I) editing, cytosine (C) to uridine (U) editing has only been previously described in organellar tRNAs. We have shown that cytoplasmic tRNAThr(AGU) undergoes two distinct editing events in the anticodon loop: C to U and A to I. In vivo, every inosine-containing tRNAThr is also C to U edited at position 32. In vitro, C to U editing stimulates conversion of A to I at the wobble base. Although …


Nutrient Control Of Microbial Carbon Cycling Along An Ombrotrophicminerotrophic Peatland Gradient, Jason K. Keller, Angela K. Bauers, Scott D. Bridgham, Laurie E. Kellogg, Colleen M. Iversen Jan 2006

Nutrient Control Of Microbial Carbon Cycling Along An Ombrotrophicminerotrophic Peatland Gradient, Jason K. Keller, Angela K. Bauers, Scott D. Bridgham, Laurie E. Kellogg, Colleen M. Iversen

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Future climate change and other anthropogenic activities are likely to increase nutrient availability in many peatlands, and it is important to understand how these additional nutrients will influence peatland carbon cycling. We investigated the effects of nitrogen and phosphorus on aerobic CH4 oxidation, anaerobic carbon mineralization (as CO2 and CH4 production), and anaerobic nutrient mineralization in a bog, an intermediate fen, and a rich fen in the Upper Peninsula of Michigan. We utilized a 5-week laboratory nutrient amendment experiment in conjunction with a 6-year field nutrient fertilization experiment to consider how the relative response to nitrogen and phosphorus differed among …


Linking Ligand-Induced Alterations In Androgen Receptor Structure To Differential Gene Expression: A First Step In The Rational Design Of Selective Androgen Receptor Modulators, Dmitri Kazmin, Tatiana Prytkova, C. Edgar Cook, Russell Wolfinger, Tzu-Ming Chu, David Beratan, J. D. Norris, Ching-Yi Chang, Donald P. Mcdonnell Jan 2006

Linking Ligand-Induced Alterations In Androgen Receptor Structure To Differential Gene Expression: A First Step In The Rational Design Of Selective Androgen Receptor Modulators, Dmitri Kazmin, Tatiana Prytkova, C. Edgar Cook, Russell Wolfinger, Tzu-Ming Chu, David Beratan, J. D. Norris, Ching-Yi Chang, Donald P. Mcdonnell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We have previously identified a family of novel androgen receptor (AR) ligands that, upon binding, enable AR to adopt structures distinct from that observed in the presence of canonical agonists. In this report, we describe the use of these compounds to establish a relationship between AR structure and biological activity with a view to defining a rational approach with which to identify useful selective AR modulators. To this end, we used combinatorial peptide phage display coupled with molecular dynamic structure analysis to identify the surfaces on AR that are exposed specifically in the presence of selected AR ligands. Subsequently, we …