Starchless mutants of Chlamydomonas reinhardtii lack the small subunit of a heterotetrameric ADP-glucose pyrophosphorylase.

ABSTRACT: ADP-glucose synthesis through ADP-glucose pyrophosphorylase defines the major rate-controlling step of storage polysaccharide synthesis in both bacteria and plants. We have isolated mutant strains defective in the STA6 locus of the monocellular green alga Chlamydomonas reinhardtii that fail to accumulate starch and lack ADP-glucose pyrophosphorylase activity. We show that this locus encodes a 514-amino-acid polypeptide corresponding to a mature 50-kDa protein with homology to vascular plant ADP-glucose pyrophosphorylase small-subunit sequences. This gene segregates independently from the previously characterized STA1 locus that encodes the large 53-kDa subunit of the same heterotetramer enzyme. Because STA1 locus mutants have retained an AGPase but exhibit lower sensitivity to 3-phosphogly

SUBMITTER: Zabawinski C 

PROVIDER: S-EPMC94975 | biostudies-literature | 2001 Feb

REPOSITORIES: biostudies-literature