Biomedical subjects

P Roesch

Publications and source records attributed to P Roesch.

5 recordsLinked to original sources

PubMed2002

Extensive mosaic structure revealed by the complete genome sequence of uropathogenic Escherichia coli.

We present the complete genome sequence of uropathogenic Escherichia coli, strain CFT073. A three-way genome comparison of the CFT073, enterohemorrhagic E. coli EDL933, and laboratory strain MG1655 reveals that, amazingly, only 39.2% of their combined (nonredundant) set of proteins actually are common to all three strains. The pathogen genomes are as different from each other as each pathogen is from the benign strain. The difference in disease potential between O157:H7 and CFT073 is reflected in the absence of genes for type III secretion system or phage- and plasmid-encoded toxins found in some classes of diarrheagenic E. coli. The CFT073 genome is particularly rich in genes that encode potential fimbrial adhesins, autotransporters, iron-sequestration systems, and phase-switch recombinases. Striking differences exist between the large pathogenicity islands of CFT073 and two other well-studied uropathogenic E. coli strains, J96 and 536. Comparisons indicate that extraintestinal pathogenic E. coli arose independently from multiple clonal lineages. The different E. coli pathotypes have maintained a remarkable synteny of common, vertically evolved genes, whereas many islands interrupting this common backbone have been acquired by different horizontal transfer events in each strain.

Acute Disease↗

PubMed1990

NMR and molecular dynamics studies of the mKr2 'zinc finger'.

We determined the structure of a 30-amino-acid 'zinc finger' motif from the mouse Kruppel-like gene mKr2 in solution in the absence of metal ions by two-dimensional NMR, distance geometry and restrained molecular dynamics methods. The most prominent secondary structural feature of the peptide is a helix extending from Ser14 to Ile20. The zinc-containing structure of the peptide was simulated by molecular dynamics calculations with restraints derived from the known geometry of the zinc ion and the ligating amino acid residues Cys6, Cys9, His22, His26. The latter structure does not deviate markedly from the set of structures determined for the zinc-free peptide, i.e. this peptide can accommodate a Zn2+ ion without major structural rearrangements. Thus, we propose that the metal ion stabilizes the existing three-dimensional peptide structural motif rather than introducing novel structural features.

Amino Acids↗

PubMed1990

Solution structure of the DNA-binding domain of the yeast transcriptional activator protein GCN4.

The solution structure of an active synthetic peptide containing both the leucine zipper and the adjacent basic domain of the yeast transcription factor GCN4 (residues 220-280) was determined by NMR. The two domains show structurally distinct behaviours. In the absence of DNA, the basic domain is, although very flexible, structured and fluctuating around a helical conformation. The leucine zipper region forms a long, uninterrupted helix. From a suitable set of NMR distances the three-dimensional structure of the leucine zipper monomeric sub-domain was calculated by distance geometry algorithms. The structure of the symmetrical parallel dimer was obtained by model building using the NMR information. A smaller peptide with the sequence of the isolated basic region (residues 1-35 of the 61 residue peptide) was also synthesized. Circular dichroism studies showed 30-40% helicity. A flexible helix spans the region between residues 8 and 21. The comparison of our results with suggested models is discussed in detail.

Algorithms↗

PubMed1984

[Not Available].

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Greece↗

PubMed1982

The structure of the EF-Tu . GDP . Me2+ complex.

The structure of the MgGDP complex at the active site of elongation factor (EF-Tu) has been investigated by using phosphorothioate analogs of GDP in the absence and presence of various metal ions, electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) measurements. The high stereoselectivity of EF-Tu for the diastereomers of guanosine 5'-O-(1-thiodiphosphate) (GDP[alpha S]) is independent of the nature of the metal ion and is caused by the interaction of the protein with the alpha-phosphate of GDP. By using GDP analogs where the oxygens at either the alpha-phosphate or the beta-phosphate have been selectively labelled with 17O and measuring their effect on the EPR spectrum of EF-Tu-bound manganese we are able to show that only the beta-phosphate of GDP is coordinated to the metal ion in the EF-Tu . Me2+ . GDP complex. 31P-NMR studies on GDP and guanosine 5'-O-(2-thiodiphosphate) (GDP[beta S]) bound to EF-Tu indicate that in the EF-Tu . Me2+ . GDP complex Mg2+ interacts more strongly with the beta-phosphate than with the alpha-phosphate. Together with binding studies using GDP[beta S] our NMR results also indicate that the protein is complexed to the beta-phosphorous of GDP via two oxygens.

Binding Sites↗