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.

• Structure and mechanism of L-fucose isomerase from Escherichia coli.

  Seemann J.E., Schulz G.E.

  The three-dimensional structure of L-fucose isomerase from Escherichia coli has been determined by X-ray crystallography at 2.5 A resolution. This ketol isomerase converts the aldose L-fucose into the corresponding ketose L-fuculose using Mn2+ as a cofactor. Being a hexamer with 64,976 Da per subu ... >> More

  The three-dimensional structure of L-fucose isomerase from Escherichia coli has been determined by X-ray crystallography at 2.5 A resolution. This ketol isomerase converts the aldose L-fucose into the corresponding ketose L-fuculose using Mn2+ as a cofactor. Being a hexamer with 64,976 Da per subunit, L-fucose isomerase is the largest structurally known ketol isomerase. The enzyme shows neither sequence nor structural similarity with other ketol isomerases. The hexamer obeys D3 symmetry and forms the crystallographic asymmetric unit. The strict and favorably oriented local symmetry allowed for a computational phase extension from 7.3 A to 2.5 A resolution. The structure was solved with an L-fucitol molecule bound to the catalytic center such that the hydroxyl groups at positions 1 and 2 are ligands of the manganese ion. Most likely, L-fucitol mimics a bound L-fucose molecule in its open chain form. The protein environment suggests strongly that the reaction belongs to the ene-diol type. << Less

  J. Mol. Biol. 273:256-268(1997) [PubMed] [EuropePMC]

• 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.