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Title: LIGHT MODULATION OF RUBISCO ACTIVATION IN SPECIES WITHOUT A LARGER ACTIVASE ISOFORM - EXISTANCE OF AN ACTIVASE REGULATORY PROTEIN?

Author
item WANG, DAFU - PLANT BIO UI URBANA
item PORTIS JR, ARCHIE

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/2002
Publication Date: 8/8/2002
Citation: N/A

Interpretive Summary:

Technical Abstract: Rubisco activase in some species like tobacco consists of only the shorter isoform. In Arabidopsis lack of the redox regulated, larger isoform results in an inability to modulate Rubisco activity in response to light intensity. However, light modulation can be observed in tobacco with characteristics suggesting redox regulation. One hypothesis for this conudrum is that another protein has completely replaced the redox regulatory function of the larger isoform in these species. A Blast search using the C-terminal 36 amino acids unique to the larger isoform did not reveal any tobacco genes, but did identify MSJ11.24, a gene of unknown function in Arabidopsis. MSJ111.24 encodes a protein of 268 amino acids of which 48 could be a chloroplast targeting sequence. Of the last 41 amino acids, 20 are similar and 14 are identical to those in activase, including two critical cysteine residues. We have cloned and expressed this protein in order to explore its properties. We want to determine if it can obtain antibodies in order to search for the existence of a similar protein in tobacco and other species.