Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1-->3)-beta-D-Glucans are major components of the cell walls of Oomycetes and as such they play an essential role in the morphogenesis and growth of these microorganisms. Despite the biological importance of (1-->3)-beta-D-glucans, their mechanisms of biosynthesis are poorly understood. Previous studies on (1-->3)-beta-D-glucan synthases from Saprolegnia monoica have shown that three protein bands of an apparent molecular weight of 34, 48 and 50 kDa co-purify with enzyme activity. However, none of the corresponding proteins have been identified. Here we have identified, purified, sequenced and characterized a protein from the 34 kDa band and clearly shown that it has all the biochemical properties of proteins from the annexin family. In addition, we have unequivocally demonstrated that the purified protein is an activator of (1-->3)-beta-D-glucan synthase. This represents a new type of function for proteins belonging to the annexin family. Two other proteins from the 48 and 50 kDa bands were identified as ATP synthase subunits, which most likely arise from contaminations by mitochondria during membrane preparation. The results, which are discussed in relation with the possible regulation mechanisms of (1-->3)-beta-D-glucan synthases, represent a first step towards a better understanding of cell wall polysaccharide biosynthesis in Oomycetes.
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PMID:Identification of the first Oomycete annexin as a (1-->3)-beta-D-glucan synthase activator. 1697 58

To understand the growth response to drought, we performed a proteomics study in the leaf growth zone of maize (Zea mays L.) seedlings and functionally characterized the role of starch biosynthesis in the regulation of growth, photosynthesis and antioxidant capacity, using the shrunken-2 mutant (sh2), defective in ADP-glucose pyrophosphorylase. Drought altered the abundance of 284 proteins overrepresented for photosynthesis, amino acid, sugar and starch metabolism, and redox-regulation. Changes in protein levels correlated with enzyme activities (increased ATP synthase, cysteine synthase, starch synthase, RuBisCo, peroxiredoxin, glutaredoxin, thioredoxin and decreased triosephosphate isomerase, ferredoxin, cellulose synthase activities, respectively) and metabolite concentrations (increased ATP, cysteine, glycine, serine, starch, proline and decreased cellulose levels). The sh2 mutant showed a reduced increase of starch levels under drought conditions, leading to soluble sugar starvation at the end of the night and correlating with an inhibition of leaf growth rates. Increased RuBisCo activity and pigment concentrations observed in WT, in response to drought, were lacking in the mutant, which suffered more oxidative damage and recovered more slowly after re-watering. These results demonstrate that starch biosynthesis contributes to maintaining leaf growth under drought stress and facilitates enhanced carbon acquisition upon recovery.
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PMID:Starch biosynthesis contributes to the maintenance of photosynthesis and leaf growth under drought stress in maize. 3248 92