5AMA

Crystal structure of the Angiotensin-1 converting enzyme N-domain in complex with amyloid-beta 1-16

Summary for 5AMA

• Entry DOI: 10.2210/pdb5ama/pdb
• Related: 5AM8 5AM9 5AMB 5AMC
• Descriptor: ANGIOTENSIN-CONVERTING ENZYME, CHLORIDE ION, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (14 entities in total)
• Functional Keywords: metalloprotease, amyloid- beta, hydrolase
• Biological source: HOMO SAPIENS (HUMAN)
• Total number of polymer chains: 4
• Total formula weight: 299937.54

Authors

Masuyer, G.,Larmuth, K.M.,Douglas, R.G.,Sturrock, E.D.,Acharya, K.R. (deposition date: 2015-03-10, release date: 2016-01-13, Last modification date: 2024-11-13)

Primary citation

Larmuth, K.M.,Masuyer, G.,Douglas, R.G.,Sturrock, E.D.,Acharya, K.R.
The Kinetic and Structural Characterisation of Amyloid-Beta Metabolism by Human Angiotensin-1- Converting Enzyme (Ace)
FEBS J., 283:1060-, 2016

PubMed Abstract: Angiotensin-1-converting enzyme (ACE), a zinc metallopeptidase, consists of two homologous catalytic domains (N and C) with different substrate specificities. Here we report kinetic parameters of five different forms of human ACE with various amyloid beta (Aβ) substrates together with high resolution crystal structures of the N-domain in complex with Aβ fragments. For the physiological Aβ(1-16) peptide, a novel ACE cleavage site was found at His14-Gln15. Furthermore, Aβ(1-16) was preferentially cleaved by the individual N-domain; however, the presence of an inactive C-domain in full-length somatic ACE (sACE) greatly reduced enzyme activity and affected apparent selectivity. Two fluorogenic substrates, Aβ(4-10)Q and Aβ(4-10)Y, underwent endoproteolytic cleavage at the Asp7-Ser8 bond with all ACE constructs showing greater catalytic efficiency for Aβ(4-10)Y. Surprisingly, in contrast to Aβ(1-16) and Aβ(4-10)Q, sACE showed positive domain cooperativity and the double C-domain (CC-sACE) construct no cooperativity towards Aβ(4-10)Y. The structures of the Aβ peptide-ACE complexes revealed a common mode of peptide binding for both domains which principally targets the C-terminal P2' position to the S2' pocket and recognizes the main chain of the P1' peptide. It is likely that N-domain selectivity for the amyloid peptide is conferred through the N-domain specific S2' residue Thr358. Additionally, the N-domain can accommodate larger substrates through movement of the N-terminal helices, as suggested by the disorder of the hinge region in the crystal structures. Our findings are important for the design of domain selective inhibitors as the differences in domain selectivity are more pronounced with the truncated domains compared to the more physiological full-length forms.

PubMed: 26748546
DOI: 10.1111/FEBS.13647

Experimental method

X-RAY DIFFRACTION (1.8 Å)