@misc{RoethleinMiettinenIgnatova2015,
  author    = {Roethlein, Christoph and Miettinen, Markus S. and Ignatova, Zoya},
  title     = {A flexible approach to assess fluorescence decay functions in complex energy transfer systems},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe 819},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe 819},
  number    = {819},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-42755},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427557},
  pages     = {12},
  year      = {2015},
  abstract  = {Background: Time-correlated Forster resonance energy transfer (FRET) probes molecular distances with greater accuracy than intensity-based calculation of FRET efficiency and provides a powerful tool to study biomolecular structure and dynamics. Moreover, time-correlated photon count measurements bear additional information on the variety of donor surroundings allowing more detailed differentiation between distinct structural geometries which are typically inaccessible to general fitting solutions. Results: Here we develop a new approach based on Monte Carlo simulations of time-correlated FRET events to estimate the time-correlated single photon counts (TCSPC) histograms in complex systems. This simulation solution assesses the full statistics of time-correlated photon counts and distance distributions of fluorescently labeled biomolecules. The simulations are consistent with the theoretical predictions of the dye behavior in FRET systems with defined dye distances and measurements of randomly distributed dye solutions. We validate the simulation results using a highly heterogeneous aggregation system and explore the conditions to use this tool in complex systems. Conclusion: This approach is powerful in distinguishing distance distributions in a wide variety of experimental setups, thus providing a versatile tool to accurately distinguish between different structural assemblies in highly complex systems.},
  language  = {en}
}
@misc{BenteleSaffertRauscheretal.2013,
  author    = {Bentele, Kajetan and Saffert, Paul and Rauscher, Robert and Ignatova, Zoya and Bluethgen, Nils},
  title     = {Efficient translation initiation dictates codon usage at gene start},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {912},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44133},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441337},
  pages     = {12},
  year      = {2013},
  abstract  = {The genetic code is degenerate; thus, protein evolution does not uniquely determine the coding sequence. One of the puzzles in evolutionary genetics is therefore to uncover evolutionary driving forces that result in specific codon choice. In many bacteria, the first 5-10 codons of protein-coding genes are often codons that are less frequently used in the rest of the genome, an effect that has been argued to arise from selection for slowed early elongation to reduce ribosome traffic jams. However, genome analysis across many species has demonstrated that the region shows reduced mRNA folding consistent with pressure for efficient translation initiation. This raises the possibility that unusual codon usage is a side effect of selection for reduced mRNA structure. Here we discriminate between these two competing hypotheses, and show that in bacteria selection favours codons that reduce mRNA folding around the translation start, regardless of whether these codons are frequent or rare. Experiments confirm that primarily mRNA structure, and not codon usage, at the beginning of genes determines the translation rate.},
  language  = {en}
}
@misc{ZhangIgnatova2009,
  author    = {Zhang, Gong and Ignatova, Zoya},
  title     = {Generic algorithm to predict the speed of translational elongation : implications for protein biogenesis},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-45007},
  year      = {2009},
  abstract  = {Synonymous codon usage and variations in the level of isoaccepting tRNAs exert a powerful selective force on translation fidelity. We have developed an algorithm to evaluate the relative rate of translation which allows large-scale comparisons of the non-uniform translation rate on the protein biogenesis. Using the complete genomes of Escherichia coli and Bacillus subtilis we show that stretches of codons pairing to minor tRNAs form putative sites to locally attenuate translation; thereby the tendency is to cluster in near proximity whereas long contiguous stretches of slow-translating triplets are avoided. The presence of slow-translating segments positively correlates with the protein length irrespective of the protein abundance. The slow-translating clusters are predominantly located down-stream of the domain boundaries presumably to fine-tune translational accuracy with the folding fidelity of multidomain proteins. Translation attenuation patterns at highly structurally and functionally conserved domains are preserved across the species suggesting a concerted selective pressure on the codon selection and species-specific tRNA abundance in these regions.},
  language  = {en}
}
@misc{DelCampoBartholomaeusFedyuninetal.2015,
  author    = {Del Campo, Cristian and Bartholom{\"a}us, Alexander and Fedyunin, Ivan and Ignatova, Zoya},
  title     = {Secondary Structure across the Bacterial Transcriptome Reveals Versatile Roles in mRNA Regulation and Function},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
  number    = {520},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-40966},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-409662},
  pages     = {23},
  year      = {2015},
  abstract  = {Messenger RNA acts as an informational molecule between DNA and translating ribosomes. Emerging evidence places mRNA in central cellular processes beyond its major function as informational entity. Although individual examples show that specific structural features of mRNA regulate translation and transcript stability, their role and function throughout the bacterial transcriptome remains unknown. Combining three sequencing approaches to provide a high resolution view of global mRNA secondary structure, translation efficiency and mRNA abundance, we unraveled structural features in E. coli mRNA with implications in translation and mRNA degradation. A poorly structured site upstream of the coding sequence serves as an additional unspecific binding site of the ribosomes and the degree of its secondary structure propensity negatively correlates with gene expression. Secondary structures within coding sequences are highly dynamic and influence translation only within a very small subset of positions. A secondary structure upstream of the stop codon is enriched in genes terminated by UAA codon with likely implications in translation termination. The global analysis further substantiates a common recognition signature of RNase E to initiate endonucleolytic cleavage. This work determines for the first time the E. coli RNA structurome, highlighting the contribution of mRNA secondary structure as a direct effector of a variety of processes, including translation and mRNA degradation.},
  language  = {en}
}
@misc{GorochowskiIgnatovaBovenbergetal.2015,
  author    = {Gorochowski, Thomas E. and Ignatova, Zoya and Bovenberg, Roel A. L. and Roubos, Johannes A.},
  title     = {Trade-offs between tRNA abundance and mRNA secondary structure support smoothing of translation elongation rate},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {816},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-44134},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441340},
  pages     = {13},
  year      = {2015},
  abstract  = {Translation of protein from mRNA is a complex multi-step process that occurs at a non-uniform rate. Variability in ribosome speed along an mRNA enables refinement of the proteome and plays a critical role in protein biogenesis. Detailed single protein studies have found both tRNA abundance and mRNA secondary structure as key modulators of translation elongation rate, but recent genome-wide ribosome profiling experiments have not observed significant influence of either on translation efficiency. Here we provide evidence that this results from an inherent trade-off between these factors. We find codons pairing to high-abundance tRNAs are preferentially used in regions of high secondary structure content, while codons read by significantly less abundant tRNAs are located in lowly structured regions. By considering long stretches of high and low mRNA secondary structure in Saccharomyces cerevisiae and Escherichia coli and comparing them to randomized-gene models and experimental expression data, we were able to distinguish clear selective pressures and increased protein expression for specific codon choices. The trade-off between secondary structure and tRNA-concentration based codon choice allows for compensation of their independent effects on translation, helping to smooth overall translational speed and reducing the chance of potentially detrimental points of excessively slow or fast ribosome movement.},
  language  = {en}
}