Membrane Proteins Have Distinct Fast Internal Motion and Residual Conformational Entropy.
Angew Chem Int Ed Engl
; 59(27): 11108-11114, 2020 06 26.
Article
em En
| MEDLINE
| ID: mdl-32277554
ABSTRACT
The internal motions of integral membrane proteins have largely eluded comprehensive experimental characterization. Here the fast side-chain dynamics of the α-helical sensory rhodopsinâ
II and the ß-barrel outer membrane proteinâ
W have been investigated in lipid bilayers and detergent micelles by solution NMR relaxation techniques. Despite their differing topologies, both proteins have a similar distribution of methyl-bearing side-chain motion that is largely independent of membrane mimetic. The methyl-bearing side chains of both proteins are, on average, more dynamic in the ps-ns timescale than any soluble protein characterized to date. Accordingly, both proteins retain an extraordinary residual conformational entropy in the folded state, which provides a counterbalance to the absence of the hydrophobic effect. Furthermore, the high conformational entropy could greatly influence the thermodynamics underlying membrane-protein functions, including ligand binding, allostery, and signaling.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Entropia
/
Proteínas de Membrana
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article