Intersubunit Interactions in Human Cytidine Deaminase

  title={Intersubunit Interactions in Human Cytidine Deaminase},
  author={Silvia Vincenzetti and Stefano Costanzi and Gloria Cristalli and Pierluigi Mariani and B. Quadrini and Natalina Cammertoni and Alberto Vita},
  journal={Nucleosides, Nucleotides \& Nucleic Acids},
  pages={1535 - 1538}
Abstract In order to design new efficient cytidine based drugs, an intersubunit interactions study related to the active site has been performed on the wild-type cytidine deaminase (CDA) and on the mutant enzyme F137W/W113F. F137 is the homologous to the Bacillus subtilis CDA F125 involved in the subunit interactions. In presence of the dissociating agent SDS, wild-type human CDA dissociate into enzymatically inactive monomers without intermediate forms via a non-cooperative transition… 


Crystal structure of the tetrameric cytidine deaminase from Bacillus subtilis at 2.0 A resolution.
The first structure of a T-CDA from Bacillus subtilis is determined and reveals that the negative charge caused by the three ligands is partly neutralized by an arginine residue hydrogen-bonded to two of the cysteine residues and the dipoles of two alpha-helices.
Cytidine deaminase. The 2.3 A crystal structure of an enzyme: transition-state analog complex.
The differences in zinc ligands, ligand-binding stereochemistry, and tertiary structures of CDA and ADA strongly suggest that the common features of transition state stabilization arose by convergent evolution.
Possible role of two phenylalanine residues in the active site of human cytidine deaminase.
Kinetic experiments and equilibrium experiments with FZEB showed that the residue W113 seems not to be part of the active site of the enzyme whereas the Phe/Trp substitution in F36W/W113F and F137W/w113F mutant enzymes had a negative effect on substrate binding and catalysis, suggesting that F137 and F36 of the wild-type CDA are involved in a stabilizing interaction between ligand and enzyme.
Identification of four amino acid residues essential for catalysis in human cytidine deaminase by site-directed mutagenesis and chemical modifications.
Kinetic measurements with the specific carboxylic group reagent N-ethoxy-carbonyl-2-eth oxygen-1,2-dihydroquinoline performed on wild-type CDA suggest that Glu67 is essential for the catalytic process, and it seems plausible that the limiting step for the maintenance of zinc in the active site is the formation of coordination between Cys99 and Cys102.
Recombinant human cytidine deaminase: expression, purification, and characterization.
The recombinant CDA has been purified to homogeneity by a rapid procedure consisting of heat inactivation followed by affinity chromatography and showed a specific activity of 105 U/mg, corresponding to about 88-fold purification with respect to the crude extract and was judged to be >98% pure by SDS-PAGE.