Comparative amino acid sequence of fructose-1,6-bisphosphatases: identification of a region unique to the light-regulated chloroplast enzyme.
AUTOR(ES)
Marcus, F
RESUMO
Chloroplast fructose-1,6-bisphosphatase (Fru-P2-ase) is an essential enzyme in the photosynthetic pathway of carbon dioxide fixation into sugars. The properties of the chloroplast enzyme are clearly distinct from cytosolic gluconeogenic Fru-P2-ases. Light-dependent activation by way of a ferredoxin/thioredoxin system and insensitivity to AMP inhibition are distinctive characteristics of the chloroplast enzyme. However, the chloroplast enzyme shows a high degree of amino acid sequence similarity to gluconeogenic Fru-P2-ases. Sequence data reported for a total of 285 residues (approximately 75% of the structure) of the spinach chloroplast enzyme reveals a 46% amino acid sequence identity with pig kidney Fru-P2-ase. We now report the amino acid sequence of a region consisting of 46 additional residues. This region is located near the middle of the primary structure of the enzyme and it includes a 16-residue insert not present in other Fru-P2-ases. This sequence insert has two cysteines separated by only 4 amino acid residues (Cys-Val-Val-Asn-Val-Cys), a characteristic feature of at least three other enzymes containing redox-active cysteines. It appears likely that this region of chloroplast Fru-P2-ase is involved in light-dependent activation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=281760Documentos Relacionados
- Antigenic relationships between chloroplast and cytosolic fructose-1,6-bisphosphatases.
- A chimeric light-regulated amino acid transport system allows the isolation of blue light regulator (blr) mutants of Neurospora crassa.
- Light-Regulated Gravitropism in Seedling Roots of Maize 1
- Complete amino acid sequence of pig kidney fructose-1,6-bisphosphatase.
- Fast light-regulated genes of Neurospora crassa.