EC Number   |
|---|
   2.4.1.37 | assignment of all methyl resonance signals in Ala, Ile, Leu, Met and Val labeled samples of GTA and GTB by lanthanide-induced pseudocontact shifts and methyl-methyl NOESY. The fully closed state is not adopted in the presence of lanthanide ions |
| 2.4.1.37 | catalytic domain with and without H-antigen and UDP, at 1.32 and 1.65 A resolution |
| 2.4.1.37 | crystals of purified native enzyme are soaked with various combinations of UDP-GalNAc, UDP-Gal, UDP, and acceptor analogues alpha-L-fucosyl-1,2-beta-D-(3-deoxy)-galactosyl-O-R or alpha-L-fucosyl-1,2-beta-D-(3-amino)-galactosyl-O-R, ligands are solved in 7.5% PEG 4000, 15% glycerol, 75 mM N-[2-acetamido]-2-iminodiacetic acid, pH 7.5, 10 mM MnCl2, and 10 mM inhibitor, 3-4 days, X-ray diffraction structure determination and analysis at 1.6 A resolution |
| 2.4.1.37 | enzyme adopts an open conformation in the absence of substrates. Binding of the donor substrate UDP-Gal or of UDP induces a semiclosed conformation. In the presence of both donor and acceptor substrates, the enzymes shift towards a closed conformation with ordering of an internal loop and the C-terminal residues, which then completely cover the donor-binding pocket. The enzyme shows substantial plasticity and conformational flexibility. Residues Ile123 at the bottom of the UDP binding pocket, and Ile192 as part of the internal loop are significantly disturbed upon stepwise addition of UDP and H-disaccharide-O-CH3 |
| 2.4.1.37 | enzyme soaked with acceptor analogs: galactose, lactose, N-acetyllactosamine, beta-D-Galp-O(CH2)8CO2CH3, alpha-L-Fucp-(1,2)-beta-D-Galp-O(CH2)7CH3, beta-D-Galp-(1,4)-beta-D-Glcp-OCH3, alpha-L-Fucp-(1,2)-beta-D-Galp-(1,3)-beta-D-GlcNAcp-O(CH2)7CH3, alpha-L-Fucp-(1,2)-beta-D-Galp-(1,4)-beta-D-GlcNAcp-O-(CH2)8CO2CH3 |
| 2.4.1.37 | in complex with UDP and galactose, using 1% (w/v) PEG 4000, 4.5-5% (w/v) 2-methyl-2,4-pentanediol, 100 mM ammonium sulfate, 70 mM sodium chloride, 50 mM N-[2-acetamido]-2-iminodiacetic acid buffer pH 7.5, 30 mM sodium acetate buffer pH 4.6 and 5 mM MnCl2 |
| 2.4.1.37 | Methyl-TROSY-based titration experiments in combination with zz-exchange experiments show dramatic changes of binding kinetics associated with allosteric interactions between donor-type and acceptor-type ligands. Binding of the acceptor substrates H-disaccharide, H-type II trisaccharide, and H-type VI trisaccharide affects the chemical shifts of the 13C-methyl groups of Met 266, Val 299, Leu 324, and Leu 329, which belong to the acceptor substrate binding pocket |
| 2.4.1.37 | mutant GTB C209A is crystallized in both the presence and the absence of mercury, 0.01 ml drops containing 6-8 mg/ml GTB, 70 mM N-(2-acetamido)-2-iminodiacetic acid, pH 7.5, 50 mM sodium acetate, pH 4.6, 40 mM NaCl, 5-8 mM MnCl2, 2.5% v/v 2-methyl-2,4-pentanediol, 5% v/v glycerol, 2% w/v PEG 4000 and 0.3-0.5 mM 3-chloromercuri-2-methoxypropylurea is suspended over 1 ml reservoir solution containing 50 mM N-(2-acetamido)-2-iminodiacetic acid, pH 7.5, 10 mM, MnCl2, 100 mM ammonium sulfate, 5% v/v MPD, 10% v/v glycerol and 8-10% w/v PEG 4000. Growing crystals of native GTB in the absence of mercury using protein concentrations of 6-8 mg /ml are unsuccessful, therefore crystals of the C209A mutant are grown from protein concentrations of over 30 mg/ml with the lowest observed concentration that yielded diffraction-quality crystals being 15 mg/ml 5-8 ml drops containing 1% PEG 4000, 4.5% MPD, 0.1 M ammonium sulfate, 0.07 M NaCl, 0.05 M N-(2-acetamido)-2-iminodiacetic acid, pH 7.5, and 5 mM CoCl2 are stored at 4-6°C for 3-5 days over a reservoir of 2.7% PEG 4000, 7% MPD, 0.32 M ammonium sulfate, 0.25 M NaCl and 0.2 M N-(2-acetamido)-2-iminodiacetic acid. Both sets of crystals are washed with mother liquor containing 6-7% PEG 4000, 70 mM N-(2-acetamido)-2-iminodiacetic acid, pH 7.5, 30 mM sodium acetate, pH 4.6, 40 mM ammonium sulfate, 29-30% glycerol and 9-10 mM MnCl2 or 5 mM CoCl2 for the heavy-metal derivative or native protein, respectively. X-ray diffraction structure determination and analysis at 1.8-2.4 A resolution |
| 2.4.1.37 | P234S-mutant, 1.55 and 1.65 A resolution, with and without H-antigen |
| 2.4.1.37 | structures of GTA, GTB and several chimeras determined by single-crystal X-ray diffraction demonstrate a range of susceptibility to the choice of cryoprotectant, in which the mobile polypeptide loops can be induced by glycerol to form the ordered closed conformation associated with substrate recognition and by MPD (hexylene glycol, 2-methyl-2,4-pentanediol) to hinder binding of substrate in the active site owing to chelation of the Mn2+ cofactor and thereby adopt the disordered open state |
