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Title: Conformational Selection as the Mechanism of Guest Binding in a Flexible Supramolecular Host

This work offers a detailed mechanistic investigation of host-guest encapsulation behavior in a new enzyme-mimetic metal-ligand host and provides the first observation of a conformational selection mechanism (as opposed to induced fit) in a supramolecular system. The Ga 4L 4 host described features a C 3-symmetric ligand motif with meta-substituted phenyl spacers, which enables the host to initially self-assemble into an S 4-symmetric structure and then subsequently isomerize to a T-symmetric tetrahedron for better accommodation of a sufficiently large guest. Selective inversion recovery 1H NMR studies provide structural insights into the self-exchange behaviors of the host and the guest individually in this dynamic system. Kinetic analysis of the encapsulation-isomerization event revealed that increasing the concentration of guest inhibits the rate of host-guest relaxation, a key distinguishing feature of conformational selection. A comprehensive study of this simple enzyme mimic provides insight into analogous behavior in biophysics and enzymology and aims to inform the design of efficient self-assembled microenvironment catalysts.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
AC02-05CH11231; DGE 1106400
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 139; Journal Issue: 23; Related Information: © 2017 American Chemical Society.; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1464149