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- Babcock, Gerald T, et al.
(författare)
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Tyrosyl radicals in enzyme catalysis: Some properties and a focus on photosynthetic water oxidation
- 1997
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Ingår i: Acta Chemica Scandinavica. - 0904-213X. ; 51:5, s. 533-540
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Tidskriftsartikel (refereegranskat)abstract
- Enzymes that require a redox-active amino acid for catalysis or function have emerged as a distinct class of proteins. For the tyrosine-based radical enzymes, we show that the spin-density distribution in the radical follows an odd alternate pattern that is invariant to within 10% across the class. General properties of the radical enzymes are summarized from which we conclude that their essential role in catalysis is to initiate substrate metabolism by hydrogen-atom abstraction. These ideas are extended to the Y-Z and Y-D tyrosines in Photosystem II and a radical-based hydrogen-atom abstraction model for water oxidation is discussed. Differences in rates of oxidation of Y-Z and Y-D by the reaction-center chlorophyll, P680(+), under various conditions, are considered and rationalized on the basis of changes in reorganization energy induced by the local protein structure and by the presence or absence of the (Mn)(4) cluster that binds substrate water.
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| 2. |
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| 3. |
- Beadle, H.W.P., et al.
(författare)
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Location Aware Mobile Computing
- 1997
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Ingår i: Proceedings of ICT '97. - : IEEE. ; , s. 1319-1324
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Beadle, H.W.P., et al.
(författare)
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Using location and environment awareness in mobile communications
- 1997
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Ingår i: Proceedings of the International Conference on Information, Communications and Signal Processing, ICICS. - : IEEE. ; , s. 1781-1785
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Konferensbidrag (refereegranskat)abstract
- We are investigating the use of badge based wearable computers to create highly mobile location and environment aware systems. When coupled to intelligent servers the badges provide an unparalleled platform for human centred information environments. This paper describes the architecture of the badge, its distributed computing environment, and presents initial results of application development trials conducted by a class of telecommunications students at KTH.
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