Organellar and cytosolic localization of four phosphoribosyl diphosphate synthase isozymes in spinach

• Published in: Plant physiology (Bethesda) Vol. 119; no. 2; pp. 497 - 505
• Main Authors: Krath, B.N, Hove-Jensen, B
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.02.1999; American Society of Plant Biologists
• Subjects: adenosine triphosphate; Agronomy. Soil science and plant productions; Amino Acid Sequence; amino acid sequences; Amino acids; Base Sequence; binding sites; Biochemistry and Macromolecular Structure; Biological and medical sciences; Chloroplasts; Chloroplasts - enzymology; Cloning, Molecular; Complementary DNA; cytosol; Cytosol - enzymology; Diphosphates; DNA; DNA, Complementary - genetics; DNA, Complementary - isolation & purification; DNA, Plant - genetics; DNA, Plant - isolation & purification; E coli; Economic plant physiology; enzyme activity; Enzymes; Escherichia coli; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; genbank/aj006940; genbank/aj006941; genbank/aj006942; genbank/aj006943; genetic complementation; Genetic Complementation Test; Isoenzymes - genetics; Isoenzymes - metabolism; isozymes; Metabolism; Mitochondria; Mitochondria - enzymology; Molecular Sequence Data; mutants; nucleotide sequences; Nutrition. Photosynthesis. Respiration. Metabolism; organelles; Organelles - enzymology; Peas; pentosyltransferases; Phylogeny; Pisum sativum; Pisum sativum - enzymology; Plant physiology and development; protein transport; Ribose-Phosphate Pyrophosphokinase - genetics; Ribose-Phosphate Pyrophosphokinase - metabolism; RNA, Messenger - genetics; RNA, Plant - genetics; Sequence Homology, Amino Acid; Spinach; Spinacia oleracea; Spinacia oleracea - enzymology; Spinacia oleracea - genetics; Phosphates; Enzyme; Isozyme; Homology; Spinacia oleracea; Synthase; Gene expression; Cytosol; Chenopodiaceae; Mitochondria; Regulation(control); Enzymatic activity; Complementary DNA; Dicotyledones; Angiospermae; N terminal-Sequence; Isolation; Spermatophyta; Experimental plant; Localization; Chloroplast; Aminoacid sequence
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.119.2.497

Four cDNAs encoding phosphoribosyl diphosphate (PRPP) synthase were isolated from a spinach (Spinacia oleracea) cDNA library by complementation of an Escherichia coli delta prs mutation. The four gene products produced PRPP in vitro from ATP and ribose-5-phosphate. Two of the enzymes (isozymes 1 and 2) required inorganic phosphate for activity, whereas the others were phosphate independent. PRPP synthase isozymes 2 and 3 contained 76 and 87 amino acid extensions, respectively, at their N-terminal ends in comparison with other PRPP synthases. Isozyme 2 was synthesized in vitro and shown to be imported and processed by pea (Pisum sativum) chloroplasts. Amino acid sequence analysis indicated that isozyme 3 may be transported to mitochondria and that isozyme 4 may be located in the cytosol. The deduced amino acid sequences of isozyme 1 and 2 and isozymes 3 and 4 were 88% and 75% identical, respectively. In contrast, the amino acid identities of PRPP synthase isozyme 1 or 2 with 3 or 4 was modest (22%-25%), but the sequence motifs for binding of PRPP and divalent cation-nucleotide were identified in all four sequences. The results indicate that PRPP synthase isozyme 3 and 4 belong to a new class of PRPP synthases that may be specific to plants.