title: 2-Carboxy-D-arabinitol 1-phosphate (CA1P) phosphatase: evidence for a wider role in plant Rubisco regulation.
abstract: The genes for CA1Pase (2-carboxy-D-arabinitol-1-bisphosphate phosphatase) from French bean, wheat, Arabidopsis and tobacco were identified and cloned. The deduced protein sequence included an N-terminal motif identical with the PGM (phosphoglycerate mutase) active site sequence [LIVM]-x-R-H-G-[EQ]-x-x-[WN]. The corresponding gene from wheat coded for an enzyme with the properties published for CA1Pase. The expressed protein lacked PGM activity but rapidly dephosphorylated 2,3-DPG (2,3-diphosphoglycerate) to 2-phosphoglycerate. DTT (dithiothreitol) activation and GSSG inactivation of this enzyme was pH-sensitive, the greatest difference being apparent at pH 8. The presence of the expressed protein during in vitro measurement of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) activity prevented a progressive decline in Rubisco turnover. This was due to the removal of an inhibitory bisphosphate that was present in the RuBP (ribulose-1,5-bisphosphate) preparation, and was found to be PDBP (D-glycero-2,3-pentodiulose-1,5-bisphosphate). The substrate specificity of the expressed protein indicates a role for CA1Pase in the removal of 'misfire' products of Rubisco.
authors: Department of Plant Sciences, Rothamsted Research, Harpenden, UK. john.andralojc@rothamsted.ac.uk
authors: Paul John
authors: PJ
authors: Andralojc
authors: Pippa J
authors: PJ
authors: Madgwick
authors: Yong
authors: Y
authors: Tao
authors: Alfred
authors: A
authors: Keys
authors: Jane L
authors: JL
authors: Ward
authors: Michael H
authors: MH
authors: Beale
authors: Jane E
authors: JE
authors: Loveland
authors: Phil J
authors: PJ
authors: Jackson
authors: Antony C
authors: AC
authors: Willis
authors: Steven
authors: S
authors: Gutteridge
authors: Martin A J
authors: MA
authors: Parry
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology; D007700:Kinetics; D008969:Molecular Sequence Data; D010428:Pentosephosphates / Q000378:metabolism; D027805:Phaseolus / Q000201:enzymology; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D013379:Substrate Specificity; D014026:Nicotiana / Q000201:enzymology; D014908:Triticum / Q000201:enzymology
chemical_list: D010428:Pentosephosphates; D010940:Plant Proteins; C054549:2-carboxyarabinitol 1-phosphate; C100392:2-carboxyarabinitol 1-phosphate phosphatase; D010744:Phosphoric Monoester Hydrolases; D012273:Ribulose-Bisphosphate Carboxylase