DAP conclusion

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Our research was able to provide a valuble insight into the function of aspartyl aminopeptidase. By examining the crystal structure the previously predicted functions of residues His82, 401, 313, 310, 320 & 324 were able to be validated and a compilation of the data from various resources has resulted in an overall understanding of how the protein functions. We propose that DAP has a dodecameric tetrahedral structure and interacts with unfolded protein substrates by allowing the unblocked N-terminus to pass through a channel in the centre of the triangular face by interacting with histiding residues 310, 320 & 324. The substrate then undergoes catalysis at the zinc catalytic centre of DAP where it is more likely to remove Asp over Glu residues. However little is still known about the structure and chemistry of the active site, also precicely what mechanism makes aspartyl aminopeptidase prefer Glu over Asp residues needs to be properly understood. Also structural data for His156 has not yet been solved, experimentally the corresponding residue in the human homologue of the protein is highly significant to catalytic function, this needs to be resolved so the actual function of this residue can be obtained. Our data also shows that other Glu and Asp residues that have been highly conserved across species do cluster around the predicted active site, indicating that many of them have a role in catalysis, however this needs to be shown experimentally and their exact roles ascertained.