TY - JOUR
T1 - Effects of Myristate on the Induced Circular Dichroism Spectra of Aripiprazole Bound to Human Serum Albumin
T2 - A Structural-Chemical Investigation
AU - Hirata, Kenshiro
AU - Kawai, Akito
AU - Chuang, Victor Tuan Giam
AU - Sakurama, Keiki
AU - Nishi, Koji
AU - Yamasaki, Keishi
AU - Otagiri, Masaki
N1 - Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.
PY - 2022/2/8
Y1 - 2022/2/8
N2 - The effects of myristate on the induced circular dichroism spectra of aripiprazole (ARP) bound to human serum albumin (HSA) were investigated. High concentrations of myristate reversed the Cotton effects induced in the ARP-HSA system. The observed ellipticities increased with increasing drug concentration up to an ARP-to-HSA molar ratio of 1:1 and then decreased, indicating that the extrinsic Cotton effects were generated by the binding of ARP molecules to the high- and low-affinity sites in HSA. The data for the concentration of free ARP show that myristate displaces ARP molecules from HSA. Moreover, the free fractions of ARP in the ARP-HSA-myristate system increased significantly when adding fusidic acid, a subdomain IB ligand. In the crystal structure of the ARP-HSA-myristate ternary complex, one ARP molecule is bound to subdomain IB, and the interaction between the carbonyl group of ARP and the aromatic ring of Tyr138 in subdomain IB is essential for binding to occur. Meanwhile, the ARP molecule in the ARP-HSA binary complex structure is bound only to subdomain IIIA. Consequently, the inversion in the extrinsic Cotton effects in the ARP-HSA system can be attributed to the modification of the geometry within the binding pocket, in addition to the transfer of ARP from subdomain IIIA to subdomain IB through the displacement as a result of the binding of myristate to subdomain IIIA.
AB - The effects of myristate on the induced circular dichroism spectra of aripiprazole (ARP) bound to human serum albumin (HSA) were investigated. High concentrations of myristate reversed the Cotton effects induced in the ARP-HSA system. The observed ellipticities increased with increasing drug concentration up to an ARP-to-HSA molar ratio of 1:1 and then decreased, indicating that the extrinsic Cotton effects were generated by the binding of ARP molecules to the high- and low-affinity sites in HSA. The data for the concentration of free ARP show that myristate displaces ARP molecules from HSA. Moreover, the free fractions of ARP in the ARP-HSA-myristate system increased significantly when adding fusidic acid, a subdomain IB ligand. In the crystal structure of the ARP-HSA-myristate ternary complex, one ARP molecule is bound to subdomain IB, and the interaction between the carbonyl group of ARP and the aromatic ring of Tyr138 in subdomain IB is essential for binding to occur. Meanwhile, the ARP molecule in the ARP-HSA binary complex structure is bound only to subdomain IIIA. Consequently, the inversion in the extrinsic Cotton effects in the ARP-HSA system can be attributed to the modification of the geometry within the binding pocket, in addition to the transfer of ARP from subdomain IIIA to subdomain IB through the displacement as a result of the binding of myristate to subdomain IIIA.
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U2 - 10.1021/acsomega.1c06220
DO - 10.1021/acsomega.1c06220
M3 - Article
AN - SCOPUS:85124121839
SN - 2470-1343
VL - 7
SP - 4413
EP - 4419
JO - ACS Omega
JF - ACS Omega
IS - 5
ER -