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- Krokowski, D, et al.
(författare)
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Yeast ribosomal P0 protein has two separate binding sites for P1/P2 proteins
- 2006
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Ingår i: Molecular Microbiology. - : Wiley. - 1365-2958 .- 0950-382X. ; 60:2, s. 386-400
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Tidskriftsartikel (refereegranskat)abstract
- The ribosome has a distinct lateral protuberance called the stalk; in eukaryotes it is formed by the acidic ribosomal P-proteins which are organized as a pentameric entity described as P0-(P1-P2)(2). Bilateral interactions between P0 and P1/P2 proteins have been studied extensively, however, the region on P0 responsible for the binding of P1/P2 proteins has not been precisely defined. Here we report a study which takes the current knowledge of the P0 - P1/P2 protein interaction beyond the recently published information. Using truncated forms of P0 protein and several in vitro and in vivo approaches, we have defined the region between positions 199 and 258 as the P0 protein fragment responsible for the binding of P1/P2 proteins in the yeast Saccharomyces cerevisiae. We show two short amino acid regions of P0 protein located at positions 199-230 and 231-258, to be responsible for independent binding of two dimers, P1A-P2B and P1B-P2A respectively. In addition, two elements, the sequence spanning amino acids 199-230 and the P1A-P2B dimer were found to be essential for stalk formation, indicating that this process is dependent on a balance between the P1A-P2B dimer and the P0 protein.
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| 2. |
- Woolway, R. Iestyn, et al.
(författare)
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Diel Surface Temperature Range Scales with Lake Size
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here we quantify the pattern and magnitude of diel temperature variability of surface waters using high-frequency data from 100 lakes. We show that the near-surface diel temperature range can be substantial in summer relative to long-term change and, for lakes smaller than 3 km(2), increases sharply and predictably with decreasing lake area. Most small lakes included in this study experience average summer diel ranges in their near-surface temperatures of between 4 and 7 degrees C. Large diel temperature fluctuations in the majority of lakes undoubtedly influence their structure, function and role in biogeochemical cycles, but the full implications remain largely unexplored.
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| 6. |
- Tchórzewski, M, et al.
(författare)
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Structural Characterization of Yeast Acidic Ribosomal P Proteins Forming the P1A-P2B Heterocomplex
- 2003
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 42:12, s. 3399-3408
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Tidskriftsartikel (refereegranskat)abstract
- Acidic ribosomal P proteins form a distinct lateral protuberance on the 60S ribosomal subunit. In yeast, this structure is composed of two heterocomplexes (P1A-P2B and P1B-P2A) attached to the ribosome with the aid of the P0 protein. In solution, the isolated P proteins P1A and P2B have a flexible structure with some characteristics of a molten globule [Zurdo, J., et al. (2000) Biochemistry 39, 8935-8943]. In this report, the structure of P1A-P2B heterocomplex from Saccharomyces cerevisiae is investigated by means of size-exclusion chromatography, chemical cross-linking, circular dichroism, light scattering, and fluorescence spectroscopy. The circular dichroism experiment shows that the complex could be ranked in the tertiary class of all- proteins, with an average -helical content of ~65%. Heat and urea denaturation experiments reveal that the P1A-P2B complex, unlike the isolated proteins, has a full cooperative transition which can be fitted into a two-state folding-unfolding model. The behavior of the complex in the presence of 2,2,2-trifluoroethanol also resembles a two-state folding-unfolding transition, further supporting the idea that the heterocomplex contains well-packed side chains. In conclusion, the P1A-P2B heterocomplex, unlike the isolated proteins, has a well-defined hydrophobic core. Consequently, the complex can put up its structure without additional ribosomal components, so the heterodimeric complex reflects the intrinsic properties of the two analyzed proteins, indicating thus that this is the only possible configuration of the P1A and P2B proteins on the ribosomal stalk structure.
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