Publications

• X-ray structures of Bacillus pallidus d-arabinose isomerase and its complex with l-fucitol.

  Takeda K., Yoshida H., Izumori K., Kamitori S.

  d-Arabinose isomerase (d-AI), also known as l-fucose isomerase (l-FI), catalyzes the aldose-ketose isomerization of d-arabinose to d-ribulose, and l-fucose to l-fuculose. Bacillus pallidus (B. pallidus) d-AI can catalyze isomerization of d-altrose to d-psicose, as well as d-arabinose and l-fucose. ... >> More

  d-Arabinose isomerase (d-AI), also known as l-fucose isomerase (l-FI), catalyzes the aldose-ketose isomerization of d-arabinose to d-ribulose, and l-fucose to l-fuculose. Bacillus pallidus (B. pallidus) d-AI can catalyze isomerization of d-altrose to d-psicose, as well as d-arabinose and l-fucose. Three X-ray structures of B. pallidus d-AI in complexes with 2-methyl-2,4-pentadiol, glycerol and an inhibitor, l-fucitol, were determined at resolutions of 1.77, 1.60 and 2.60 A, respectively. B. pallidus d-AI forms a homo-hexamer, and one subunit has three domains of almost equal size; two Rossmann fold domains and a mimic of the (beta/alpha) barrel fold domain. A catalytic metal ion (Mn(2+)) was found in the active site coordinated by Glu342, Asp366 and His532, and an additional metal ion was found at the channel for the passage of a substrate coordinated by Asp453. The X-ray structures basically supported the ene-diol mechanism for the aldose-ketose isomerization by B. pallidus d-AI, as well as Escherichia coli (E. coli) l-FI, in which Glu342 and Asp366 facing each other at the catalytic metal ion transfer a proton from C2 to C1 and O1 to O2, acting as acid/base catalysts, respectively. However, considering the ionized state of Asp366, the catalytic reaction also possibly occurs through the negatively charged ene-diolate intermediate stabilized by the catalytic metal ion. A structural comparison with E. colil-FI showed that B. pallidus d-AI possibly interconverts between "open" and "closed" forms, and that the additional metal ion found in B. pallidus d-AI may help to stabilize the channel region. << Less

  Biochim Biophys Acta 1804:1359-1368(2010) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Properties of D-arabinose isomerase purified from two strains of Escherichia coli.

  Boulter J.R., Gielow W.O.

  d-Arabinose isomerase (EC 5.3.1.3) has been isolated from l-fucose-induced cultures of Escherichia coli K-12 and d-arabinose-induced cultures of E. coli B/r. Both enzymes were homogeneous in an ultracentrifuge and migrated as single bands upon disc electrophoresis in acrylamide gels. The s(20,w) w ... >> More

  d-Arabinose isomerase (EC 5.3.1.3) has been isolated from l-fucose-induced cultures of Escherichia coli K-12 and d-arabinose-induced cultures of E. coli B/r. Both enzymes were homogeneous in an ultracentrifuge and migrated as single bands upon disc electrophoresis in acrylamide gels. The s(20,w) was 14.5 x 10(-13) sec for the E. coli K-12 enzyme and 14.3 x 10(-13) sec for the E. coli B/r enzyme. The molecular weight, determined by high-speed sedimentation equilibrium, was 3.55 +/- 0.06 x 10(5) for the E. coli K-12 enzyme and 3.42 +/-0.04 x 10(5) for the enzyme isolated from E. coli B/r. Both enzyme preparations were active wth l-fucose or d-arabinose as substrates and showed no activity on any of the other aldopentoses or aldohexoses tested. With the E. coli K-12 enzyme, the K(m) was 2.8 x 10(-1)m for d-arabinose and 4.5 x 10(-2)m for l-fucose; with the E. coli B/r enzyme, the K(m) was 1.7 x 10(-1)m for d-arabinose and 4.2 x 10(-2)m for l-fucose. Both enzymes were inhibited by several of the polyalcohols tested, ribitol, l-arabitol, and dulcitol being the strongest. Both enzymes exhibited a broad plateau of optimal catalytic activity in the alkaline range. Both enzymes were stimulated by the presence of Mn(2+) or Co(2+) ions, but were strongly inhibited by the presence of Cd(2+) ions. Both enzymes were precipitated by antisera prepared against either enzyme preparation. The amino acid composition for both proteins has been determined; a striking similarity has been detected. Both enzymes could be dissociated, by protonation at pH 2 or by dialysis against buffer containing 8 m urea, into subunits that were homogeneous in an ultracentrifuge and migrated as single bands on disc electrophoresis in acrylamide gels containing urea. The molecular weight of the subunit, determined by high-speed sedimentation equilibrium, was 9.09 +/-0.2 x 10(4) for the enzyme from E. coli K-12 and 8.46 +/-0.1 x 10(4) for the enzyme from E. coli B/r. On the basis of biophysical studies, both isomerases appear to be oligomeric proteins consisting of four identical subunits. << Less

  J. Bacteriol. 113:687-696(1973) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Metabolism of D-arabinose: a new pathway in Escherichia coli.

  LeBlanc D.J., Mortlock R.P.

  Several growth characteristics of Escherichia coli K-12 suggest that growth on l-fucose results in the synthesis of all the enzymes necessary for growth on d-arabinose. Conversely, when a mutant of E. coli is grown on d-arabinose, all of the enzymes necessary for immediate growth on l-fucose are p ... >> More

  Several growth characteristics of Escherichia coli K-12 suggest that growth on l-fucose results in the synthesis of all the enzymes necessary for growth on d-arabinose. Conversely, when a mutant of E. coli is grown on d-arabinose, all of the enzymes necessary for immediate growth on l-fucose are present. Three enzymes of the l-fucose pathway in E. coli, l-fucose isomerase, l-fuculokinase, and l-fuculose-l-phospháte aldolase possess activity on d-arabinose, d-ribulose, and d-ribulose-l-phosphate, respectively. The products of the aldolase, with d-ribulose-l-phosphate as substrate, are dihydroxyacetone phosphate and glycolaldehyde. l-Fucose, but not d-arabinose, is capable of inducing these activities in wild-type E. coli. In mutants capable of utilizing d-arabinose as sole source of carbon and energy, these activities are induced in the presence of d-arabinose and in the presence of l-fucose. Mutants unable to utilize l-fucose, selected from strains capable of growth on d-arabinose, are found to have lost the ability to grow on d-arabinose. Enzymatic analysis of cell-free extracts, prepared from cultures of these mutants, reveals that a deficiency in any of the l-fucose pathway enzymes results in the loss of ability to utilize d-arabinose. Thus, the pathway of d-arabinose catabolism in E. coli K-12 is believed to be: d-arabinose right harpoon over left harpoon d-ribulose --> d-ribulose-l-phosphate right harpoon over left harpoon dihydroxyacetone phosphate plus glycolaldehyde. Evidence is presented which suggests that the glycolaldehyde is further oxidized to glycolate. << Less

  J. Bacteriol. 106:90-96(1971) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.