title: Purification, cloning and expression of spinach leaf sucrose-phosphate synthase in Escherichia coli.
abstract: Sucrose-phosphate synthase (SPS) from leaves of spinach (Spinacia oleracea L.) has been purified to homogeneity by a procedure involving precipitation with polyethylene glycol and chromatography over diethylaminoethylcellulose, omega-aminohexyl-agarose, Mono Q and Blue Affinity columns. The purification factor was 838 and the final specific activity was 1.3 nkat.(mg protein)-1. On denaturing gels the major polypeptide was 120 kDa but there was also a variable amount of smaller polypeptides in the range of 90 to 110 kDa. A new activity stain was developed to allow visualization of SPS in gels. The holoenzyme had a molecular weight of about 240 and 480 kDa in native gels and Sepharose, respectively. A high-titre polyclonal antibody was obtained which reacted with SPS from other species including wheat, potato, banana and maize. Screening of a spinach-leaf cDNA-expression library with the antibody allowed the isolation of a full-length clone. Sequencing revealed a predicted molecular weight of 117649 Da, and considerable homology with the recently published sequence for maize leaf (Worrell et al. 1991, Plant Cell 3, 1121-1130). Expression of the spinach-leaf SPS gene in Escherichia coli resulted in biological activity, revealed by the presence of SPS activity in extracts and the accumulation of sucrose-6-phosphate and sucrose in the bacteria.
authors.affiliation: Institut für Genbiologische Forschung, Berlin, FRG.
authors.forename: U
authors.initials: U
authors.lastname: Sonnewald
authors.forename: W P
authors.initials: WP
authors.lastname: Quick
authors.forename: E
authors.initials: E
authors.lastname: MacRae
authors.forename: K P
authors.initials: KP
authors.lastname: Krause
authors.forename: M
authors.initials: M
authors.lastname: Stitt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA; D004926:Escherichia coli; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010944:Plants / Q000201:enzymology* / Q000235:genetics; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D003313:Zea mays / Q000201:enzymology
chemical_list: D000906:Antibodies; D004247:DNA; D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase