Dynamics of a mobile loop at the active site of Escherichia coli asparaginase.

@article{Aung2000DynamicsOA,
  title={Dynamics of a mobile loop at the active site of Escherichia coli asparaginase.},
  author={Hnin Pwint Aung and Marco Bocola and S Schleper and Klaus-Heinrich R{\"o}hm},
  journal={Biochimica et biophysica acta},
  year={2000},
  volume={1481 2},
  pages={
          349-59
        }
}
Revealing Escherichia coli type II l-asparaginase active site flexible loop in its open, ligand-free conformation
TLDR
The structure of EcAII wild type in its open conformation is reported for the first time comprising, for at least one protomer, clear electron density for the active site flexible loop (PDB ID: 6YZI).
Probing the Dynamics of a Mobile Loop above the Active Site of L1, a Metallo-β-lactamase from Stenotrophomonas maltophilia, via Site-directed Mutagenesis and Stopped-flow Fluorescence Spectroscopy*
TLDR
A site-directed mutant of metallo-β-lactamase L1 was engineered that contained a Trp residue on the loop to serve as a fluorescent probe, and the motion of the loop was revealed to be similar to the formation rate of a reaction intermediate.
Catalytic Role of the Substrate Defines Specificity of Therapeutic l-Asparaginase.
Engineering the substrate specificity of Escherichia coli asparaginase II. Selective reduction of glutaminase activity by amino acid replacements at position 248
TLDR
It is found that replacements of A sp248 affected glutamine turnover much more strongly than asparagine hydrolysis in variant N248A, and modeling studies suggested that the selective reduction of glutaminase activity is the result of small conformational changes that affect active‐site residues and catalytically relevant water molecules.
Preliminary crystallographic studies of Y25F mutant of periplasmic Escherichia coli L-asparaginase.
TLDR
Kinetic studies show that the loss of the phenolic hydroxyl group at position 25 brought about by the replacement of Y with F strongly impairs kcat without significantly affecting Km.
Tackling Critical Catalytic Residues in Helicobacter pylori l-Asparaginase
TLDR
Some critical amino acids forming the active site of HpASNase (T16, T95 and E289) have been tackled by rational engineering in the attempt to better define their role in catalysis and to achieve a deeper understanding of the peculiar cooperative behavior of this enzyme.
Do bacterial L-asparaginases utilize a catalytic triad Thr-Tyr-Glu?
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Probing the role of threonine and serine residues of E. coli asparaginase II by site-specific mutagenesis.
TLDR
Data indicate that the hydroxyl group of Thr12 is directly involved in catalysis, probably by favorably interacting with a transition state or intermediate in Escherichia coli asparaginase II.
States and functions of tyrosine residues in Escherichia coli asparaginase II.
TLDR
P pH titration curves and 1H-NMR signals of a peculiar ligand-sensitive tyrosine residue were assigned to Y25 suggest that a peptide loop which shields the active site during catalysis is highly flexible in the free enzyme.
Structural characterization of Pseudomonas 7A glutaminase-asparaginase.
TLDR
It is suggested that the flexible loops actively participate in the transport of substrate and product molecules through the amidohydrolase active sites and participate in orienting the substrate molecules properly in relation to the catalytic residues.
Site-specific mutagenesis of Escherichia coli asparaginase II. None of the three histidine residues is required for catalysis.
TLDR
Site-specific mutagenesis was used to replace the three histidine residues of Escherichia coli asparaginase II with other amino acids, and 1H-NMR and fluorescence spectroscopy indicate that His87 is located in the interior of the protein, possibly adjacent to the active site.
Detection and characterization of intermediates in the folding of large proteins by the use of genetically inserted tryptophan probes.
L-Lactate dehydrogenase from Bacillus stearothermophilus was rebuilt by using site-directed mutagenesis to produce an enzymically active, tryptophan-less enzyme by replacing all the wild-type
Crystal structure of Escherichia coli L-asparaginase, an enzyme used in cancer therapy.
TLDR
The crystal structure of Escherichia coli asparaginase II (EC 3.5.1), a drug used for the treatment of acute lymphoblastic leukemia, has been determined and locations for the active sites between the N- and C-terminal domains belonging to different subunits are proposed and postulate a catalytic role for Thr-89.
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