Evaluation of a possible role of Stigmatella aurantiaca ACE in Aβ peptide degradation: a molecular modeling approach.

Amyloid-β (Aβ)-degrading enzymes are known to degrade Aβ peptides, a causative agent of Alzheimer's disease. These enzymes are responsible for maintaining Aβ concentration. However, loss of such enzymes or their Aβ-degrading activity because of certain genetic as well as nongenetic reasons initiates the accumulation of Aβ peptides in the human brain. Considering the limitations of the human enzymes in clearing Aβ peptide, the search for microbial enzymes that could cleave Aβ is necessary. Hence, we built a three-dimensional model of angiotensin-converting enzyme (ACE) from Stigmatella aurantiaca using homology modeling technique. Molecular docking and molecular dynamics simulation techniques were used to outline the possible cleavage mechanism of Aβ peptide. These findings suggest that catalytic residue Glu 434 of the model could play a crucial role to degrade Aβ peptide between Asp 7 and Ser 8. Thus, ACE from S. aurantiaca might cleave Aβ peptides similar to human ACE and could be used to design new therapeutic strategies against Alzheimer's disease.