| 1. |
- Lehtio, J., et al.
(författare)
-
The binding specificity and affinity determinants of family 1 and family 3 cellulose binding modules
- 2003
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 100:2, s. 484-489
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose binding modules (CBMs) potentiate the action of cellulolytic enzymes on insoluble substrates. Numerous studies have established that three aromatic residues on a CBM surface are needed for binding onto cellulose crystals and that tryptophans contribute to higher binding affinity than tyrosines. However, studies addressing the nature of CBM-cellulose interactions have so far failed to establish the binding site on cellulose crystals targeted by CBMs. In this study, the binding sites of CBMs on Valonia cellulose crystals have been visualized by transmission electron microscopy. Fusion of the CBMs with a modified staphylococcal protein A (ZZ-domain) allowed direct immuno-gold labeling at close proximity of the actual CBM binding site. The transmission electron microscopy images provide unequivocal evidence that the fungal family 1 CBMs as well as the family 3 CBM from Clostridium thermocellum CipA have defined binding sites on two opposite corners of Valonia cellulose crystals. In most samples these corners are worn to display significant area of the hydrophobic (110) plane, which thus constitutes the binding site for these CBMs.
|
|
| 2. |
- Sugiyama, K., et al.
(författare)
-
Tritium profile in plasma-facing components following D-D operation
- 2004
-
Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 329-33, s. 874-879
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated the tritium depth profile near the surface of the limiter/divertor tiles used in the deuterium fueled machines, such as TEXTOR, TFTR and JT-60U by means of the imaging plate technique and a tritium survey monitor. Tritium depth profiles near the surface of the sample tiles were estimated by comparing the experimental results to a calculation using a 3-D Monte-Carlo code. In every sample tile, there was little tritium in the range from the surface to 1 mum depth. In contrast, tritium density tended to increase beyond 1 mum depth. These results indicate that the tritium retained near the surface was easily removed by isotope exchange with a deuterium plasma or various other tritium removal operations. On the other hand, such operations did not remove tritium retained beyond 1 mum depth, and this could be a potential issue in a next D-T machine.
|
|
