#METAL ION BONDING METHIONINE PDF#

The active site consists of five conserved residues surrounding two metal ions that are 'connected' by a bridging water molecule. Co(II) activates all MetAPs known so far but also Mn(II) seems a promising candidate. This enzyme is metal dependent, although the identity of the metal ion is not yet entirely clear. Experiments with fumagillin, a covalent inhibitor that inhibits angiogenesis, confirmed computational studies trying to calculate the protonation state of the active site. coli methionine aminopeptidase (MetAP), an assay system was developed.

#METAL ION BONDING METHIONINE PDF#

Overall, the work described here provides new understanding and avenues for enzymological pursuits of MetAP, PDF and similar valuable targets.Īfter the expression and purification of the E. The evidence suggests additional roles for the C-terminal domain in regulating PDF. The truncated form of PDF lacking the C-terminal domain was found to be remarkably robust with the secondary structure as well as catalytic activity being very resistant to loss by heat. The C-terminal domain of PDF is implicated in imparting highly unusual properties to PDF, hence the stability of PDF was characterized with respect to this domain. These properties allowed the characterization of MetAP-metal-ion binding with various metals, and this represents the most comprehensive study of the MetAP metal-ion interactions. Moreover, europium was found to catalytically activate MetAP. The metal-ion binding iii properties of MetAP were studied and in this effort, the luminescence of the trivalent lanthanide ion europium was identified as a convenient signal for monitoring metal- ion binding to the enzyme. While attempting to enhance the solubility of the tight-binding inhibitors using cyclodextrins, a novel substrate-driven mode of enzyme inhibition by 2-hydroxypropyl-β-cyclodextrin was discovered. The inhibitor-enzyme interactions were further studied via steady-state and transient kinetic methods. Potent inhibitors of MetAP were identified by screening a focused library of compounds and potential pharmacophores were determined. The catalytic properties of these enzymes were studied using a combination of direct and coupled spectrometric assays. coli isoforms of MetAP and PDF in order to understand the unique characteristics of these bacterial enzymes. This investigation is a study of the biochemical and biophysical features of the E. However, in spite of great interest in the bacterial forms of these enzymes as potent antibiotic targets, efforts to develop such agents have failed. As a result, the various isoforms of MetAP and PDF have been successfully targeted by antimalarial and anti-cancer drugs. These enzymes are involved in the co-translational modification of nascent polypeptides, affecting majority of the cellular proteome across all the kingdoms of living organisms. In the search for novel antibiotic and therapeutic targets, methionine aminopeptidase (MetAP) and peptide deformylase (PDF) have recently been identified as eminently compelling. By contrast, the nature of the oxygen bridging the metal ions within the metal binding site of eMetAP-1 cannot be determined based on the results here, due to the similar structural results obtained with a bridging water molecule and a bridging hydroxide ion. Within the site of hMetAP-2 the results strongly indicate that a hydroxide ion bridges the metal ions. Another important structural issue is the identity of the bridging oxygen, which is part of either a water molecule or a hydroxide ion. coli methionine aminopeptidase type I (eMetAP- 1). This was the case for both of the systems studied one based on the X-ray structure of the human methionine aminopeptidase type 2 (hMetAP-2) and the other based on the X-ray structure of the E. The calculations showed that the structure of the site was not influenced by the identity of the metal ions. The structure of this site with either Co2+ ions or Zn2+ ions was investigated using density functional theory. All methionine aminopeptidases exhibit the same conserved metal binding site.

Metal ion bonding methionine