1dcu
From Proteopedia
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REDOX SIGNALING IN THE CHLOROPLAST: STRUCTURE OF OXIDIZED PEA FRUCTOSE-1,6-BISPHOSPHATE PHOSPHATASE
Overview
Sunlight provides the energy source for the assimilation of carbon dioxide, by photosynthesis, but it also provides regulatory signals that switch on, specific sets of enzymes involved in the alternation of light and dark, metabolisms in chloroplasts. Capture of photons by chlorophyll pigments, triggers redox cascades that ultimately activate target enzymes via the, reduction of regulatory disulfide bridges by thioredoxins. Here we report, the structure of the oxidized, low-activity form of chloroplastic, fructose-1, 6-bisphosphate phosphatase (FBPase), one of the four enzymes, of the Calvin cycle whose activity is redox-regulated by light. The, regulation is of allosteric nature, with a disulfide bridge promoting the, disruption of the catalytic site across a distance of 20 A. Unexpectedly, regulation of plant FBPases by thiol-disulfide interchange differs in, every respect from the regulation of mammalian gluconeogenic FBPases by, AMP. We also report a second crystal form of oxidized FBPase whose, tetrameric structure departs markedly from D(2) symmetry, a rare event in, oligomeric structures, and the structure of a constitutively active mutant, that is unable to form the regulatory disulfide bridge. Altogether, these, structures provide a structural basis for redox regulation in the, chloroplast.
About this Structure
1DCU is a Single protein structure of sequence from Pisum sativum. Active as Fructose-bisphosphatase, with EC number 3.1.3.11 Full crystallographic information is available from OCA.
Reference
Redox signalling in the chloroplast: structure of oxidized pea fructose-1,6-bisphosphate phosphatase., Chiadmi M, Navaza A, Miginiac-Maslow M, Jacquot JP, Cherfils J, EMBO J. 1999 Dec 1;18(23):6809-15. PMID:10581254
Page seeded by OCA on Tue Nov 20 13:10:51 2007
