Eukaryotic methionyl aminopeptidases: two classes of cobalt-dependent enzymes.

Abstract

Using partial amino acid sequence data derived from porcine methionyl aminopeptidase (MetAP; methionine aminopeptidase, peptidase M; EC 3.4.11.18), a fulllength clone of the homologous human enzyme has been obtained. The cDNA sequence contains 2569 nt with a single open reading frame corresponding to a protein of 478 amino acids. The C-terminal portion representing the catalytic domain shows limited identity with MetAP sequences from various prokaryotes and yeast, while the N terminus is rich in charged amino acids, including extended strings of basic and acidic residues. These highly polar stretches likely result in the spuriously high observed molecular mass (67 kDa). This cDNA sequence is highly similar to a rat protein, termed p67, which was identified as an inhibitor of phosphorylation of initiation factor eIF2a and was previously predicted to be a metallopeptidase based on limited sequence homology. Model building established that human MetAP (p67) could be readily accommodated into the Escherichia coli MetAP structure and that the Co2+ ligands were fully preserved. However, human MetAP was found to be much more similar to a yeast open reading frame that differed markedly from the previously reported yeast MetAP. A similar partial sequence from Methanothermusfervidus suggests that this p67-like sequence is also found in prokaryotes. These findings suggest that there are two cobalt-dependent MetAP families, presently composed of the prokaryote and yeast sequences (and represented by the E. coli structure) (type I), on the one hand, and by human MetAP, the yeast open reading frame, and the partial prokaryotic sequence (type II), on the other.

Correlation of tumor growth suppression and methionine aminopetidase-2 activity blockade using an orally active inhibitor

“…This line has amplified N-myc, which is characteristic of the most aggressive neuroblastomas seen in cancer patients (19). The CHP-134 tumor was staged at 200 mm 3 Reference residues include His-231, the residue alkylated by fumagilin and its semisynthetic derivatives (23), and Tyr-444, which terminates the 60-aa insert that forms a portion of the hydrophobic pocket of the MetAP2 active site. by twice-daily oral gavages.…”

“…PC-3 cells were inoculated in the flank of SCID male mice. Treatment was initiated when the tumors reached 150 mm 3 . As shown in Fig.…”

“…In the majority of cellular proteins, the methionine is removed cotranslationally (1), and this removal of the initiator methionine is required for proper function of these proteins, i.e., activity, localization, and stability. N-terminal methionine processing is accomplished by the action of two intracellular metalloproteases: methionine aminopeptidase 1 and 2 (MetAP1 and MetAP2) (2,3). Recently, evidence for an additional mammalian enzyme, MAP1D (or MetAP3), has been shown (4).…”

Suppression of inflammation and structural damage in experimental arthritis through molecular targeted therapy with PPI‐2458

“…Methionine aminopeptidase type 2 is a cotranslational regulator of protein synthesis involved in N-terminal protein processing, and recent functional studies have demonstrated that this enzyme is an important molecular regulator of mammalian cell growth (20)(21)(22)(23). PPI-2458 is a potent inhibitor of the in vitro proliferation of activated human umbilical vein endothelial cells (HUVECs) and human fibroblast-like synoviocytes (FLS) from RA patients, both cell types that directly contribute to the pathogenesis of RA (18,23).…”

Structural Analysis and Bioengineering of Thermostable Pyrococcus furiosus Prolidase for the Optimization of Organophosphorus Nerve Agent Detoxification

“…The Zn atoms in the A. proteolytica aminopeptidase can be replaced in vitro with cobalt atoms, and like P. furiosus prolidase, is isolated with one metal ion per active site (Bennett and Holz 1997). Prior to the isolation of P. furiosus prolidase, the only other known naturally occurring Co-dependent enzymes from this family of enzymes were the methionine aminopeptidases (MAP), which also contain 2 Co 2+ per active site (Arfin et al 1995).…”