| 1. |
- Fedorov, R V, et al.
(författare)
-
Structure of ribosomal protein TL5 complexed with RNA provides new insights into the CTC family of stress proteins
- 2001
-
Ingår i: Acta Crystallographica. Section D: Biological Crystallography. - 1399-0047. ; D57:7, s. 968-976
-
Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of Thermus thermophilus ribosomal protein TL5 in complex with a fragment of Escherichia coli 5S rRNA has been determined at 2.3 Å resolution. The protein consists of two domains. The structure of the N-terminal domain is close to the structure of E. coli ribosomal protein L25, but the C-terminal domain represents a new fold composed of seven -strands connected by long loops. TL5 binds to the RNA through its N-terminal domain, whereas the C-terminal domain is not included in this interaction. Cd2+ ions, the presence of which improved the crystal quality significantly, bind only to the protein component of the complex and stabilize the protein molecule itself and the interactions between the two molecules in the asymmetric unit of the crystal. The TL5 sequence reveals homology to the so-called general stress protein CTC. The hydrophobic cores which stabilize both TL5 domains are highly conserved in CTC proteins. Thus, all CTC proteins may fold with a topology close to that of TL5.
|
|
| 2. |
|
|
| 3. |
- Aspholm-Hurtig, Marina, et al.
(författare)
-
Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
-
Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
-
Tidskriftsartikel (refereegranskat)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
|
|
| 4. |
- Garg, N., et al.
(författare)
-
Distributed Long-Lived List Colouring: How to Dynamically Allocate Frequencies in Cellular Networks
- 2002
-
Ingår i: Wireless Networks. - 1022-0038 .- 1572-8196. ; 8:1, s. 49-60
-
Tidskriftsartikel (refereegranskat)abstract
- To avoid signal interference in mobile communication it is necessary that the frequencies used for communication within each cell are allocated so that no signal interference occurs with neighbouring cells. We model this channel allocation problem as a generalised list colouring problem and we show how to analytically measure and provide worst-case guarantees regarding request satisfiability. To the best of our knowledge, this has not been done before and gives a now perspective to the problem, as well as a clear direction for further investigation. We propose distributed approaches for solving the problem, which are able to adapt fast to temporal variations in channel demands in different cells, as well as to cope with crash failures, by limiting the failure-locality - the size of the network that can be affected by a faulty station, in terms of the distance from that station. Our first approach is inspired by a relatively recent theorem relating graph colourings and orientations; it achieves the equivalent of the best known sequentially achievable upper bound for request satisfiability, implied by the theorem. It also employs a powerful synchronisation mechanism to achieve worst-case response time that depends only on A - the degree of the signal interference graph - and failure locality 4. Our second proposal is a first approach towards exploring what bound in request satisfiability is achievable without the use of extra synchronisation; by employing randomisation in frequency choices, in only one round of communication, a base station can expect to pick f/(4Delta) frequencies, where f is the size of the list at the node; the failure locality of this solution is only 1.
|
|
| 5. |
|
|
