bi0c00294_si_002.mpg (700.91 kB)
Linkage between Proximal and Distal Movements of P450cam Induced by Putidaredoxin
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posted on 2020-05-14, 13:12 authored by Shu-Hao Liou, Shih-Wei Chuo, Yudong Qiu, Lee-Ping Wang, David B. GoodinPutidaredoxin (Pdx)
is the exclusive reductase and a structural
effector for P450cam (CYP101A1). However, the mechanism of how Pdx
modulates the conformational states of P450cam remains elusive. Here
we report a putative communication pathway for the Pdx-induced conformational
change in P450cam using results of double electron–electron
resonance (DEER) spectroscopy and molecular dynamics simulations.
Use of solution state DEER measurements allows us to observe subtle
conformational changes in the internal helices in P450cam among closed,
open, and P450cam–Pdx complex states. Molecular dynamics simulations
and dynamic network analysis suggest that Pdx binding is coupled to
small coordinated movements of several regions of P450cam, including
helices C, B′, I, G, and F. These changes provide a linkage
between the Pdx binding site on the proximal side of the enzyme and
helices F/G on the distal side and the site of the largest movement
resulting from the Pdx-induced closed-to-open transition. This study
provides a detailed rationale for how Pdx exerts its long-recognized
effector function at the active site from its binding site on the
opposite face of the enzyme.