Structural basis for the light regulation of chloroplast NADP malate dehydrogenase.
In: Physiologia Plantarum, Jg. 110 (2000-11-01), Heft 3, S. 314-321
Online
academicJournal
Zugriff:
The activity of chloroplast NADP-malate dehydrogenase (NADP-MDH; EC 1.1.1.82) in both C3 and C4 plants is regulated by light intensity. In darkness, the activity of the enzyme can be less than 1% of the maximal activity found at high light intensities. The extent of activation in the light is dynamic, responding rapidly to changes in light intensity and adapting to changes in photosynthetic rate. Enzyme activation is caused by thioredoxin-catalyzed reduction of two regulatory disulfide bonds, while inactivation is accomplished by thioredoxin-catalyzed re-oxidation. In the case of NADP-MDH, the coenzyme substrates NADP+ and NADPH modify the rate of this interconversion and seem to be important to the extent of activation in vivo. The recent determination of the X-ray structure of the oxidized, dark form of NADP-MDH from the C4 plants Flaveria bidentis and Sorghum shows how oxidation of a disulfide bond can inactivate the enzyme. This review discusses the various structural features of NADP-MDH that seem to be responsible for the regulatory properties of the enzyme and emphasizes that large changes of activity can be accomplished by multiple, small, reinforcing changes rather than a single large change in a signal molecule concentration. [ABSTRACT FROM AUTHOR]
Copyright of Physiologia Plantarum is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Titel: |
Structural basis for the light regulation of chloroplast NADP malate dehydrogenase.
|
---|---|
Autor/in / Beteiligte Person: | Ashton, Anthony R. ; Trevanion, Stephen J. ; Carr, Paul D. ; Verger, Denis ; Ollis, David L. |
Link: | |
Zeitschrift: | Physiologia Plantarum, Jg. 110 (2000-11-01), Heft 3, S. 314-321 |
Veröffentlichung: | 2000 |
Medientyp: | academicJournal |
ISSN: | 0031-9317 (print) |
DOI: | 10.1034/j.1399-3054.2000.1100305.x |
Schlagwort: |
|
Sonstiges: |
|