21. |
|
|
22. |
|
|
23. |
|
|
24. |
|
|
25. |
|
|
26. |
- Woestenenk, Esmeralda A., et al.
(författare)
-
The solution structure of ribosomal protein L18 from Thermus thermophilus reveals a conserved RNA-binding fold
- 2002
-
Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 363:3, s. 553-561
-
Tidskriftsartikel (refereegranskat)abstract
- We have determined the solution structure of ribosomal protein L18 from Thermus thermophilus. L18 is a 12.5 kDa protein of the large subunit of the ribosome and binds to both 5 S and 23 S rRNA. In the uncomplexed state L18 folds to a mixed α/β globular structure with a long disordered N-terminal region. We compared our high-resolution structure with RNA-complexed L 18 from Haloarcula marismortui and T. thermophilus to examine RNA-induced as well as species-dependent structural differences. We also identified T. thermophilus S11 as a structural homologue and found that the structures of the RNA-recognition sites are conserved. Important features, for instance a bulge in the RNA-contacting β-sheet, are conserved in both proteins. We suggest that the L18 fold recognizes a specific RNA motif and that the resulting RNA-protein-recognition module is tolerant to variations in sequence.
|
|
27. |
|
|
28. |
|
|
29. |
|
|
30. |
- Abrahamson, Magnus, et al.
(författare)
-
Human cystatin C: Role of the N-terminal segment in the inhibition of human cysteine proteinases and in its inactivation by leucocyte elastase
- 1991
-
Ingår i: Biochemical Journal. - 0264-6021. ; 273:3, s. 621-626
-
Tidskriftsartikel (refereegranskat)abstract
- Leucocyte elastase in catalytic amounts was observed to rapidly cleave the Val-10-Gly-11 bond of the human cysteine-proteinase inhibitor cystatin C at neutral pH. The resulting modified inhibitor had size and amino acid composition consistent with a cystatin C molecule devoid of the N-terminal Ser-1-Val-10 decapeptide. Leucocyte-elastase-modified cystatin C had more than 240-fold lower affinity than native cystatin C for papain. Removal of the N-terminal decapeptide of human cystatin C also decreased inhibition of human cathepsins B and L by three orders of magnitude, but decreased inhibition of cathepsin H by only 5-fold. A tripeptidyldiazomethane analogue of of the N-terminal portion of cystatin C was a good inhibitor of cathepsins B and L but a poor inhibitor of cathepsin H. It therefore appears that amino acid side chains of the N-terminal segment of cystatin C bind in the substrate-binding pockets of cathepsins B and L but not in those of cathepsin H. It is argued that the N-terminal cystatin C interaction with cathepsin B is physiologically important and hence that leucocyte elastase could have a function as a regulator of extracellular cysteine-proteinase inhibitory activity at sites of inflammation.
|
|