Coupling X-Ray Reflectivity and In Silico Binding to Yield Dynamics of Membrane Recognition by Tim1.
Biophys J
; 113(7): 1505-1519, 2017 Oct 03.
Article
en En
| MEDLINE
| ID: mdl-28978444
The dynamic nature of lipid membranes presents significant challenges with respect to understanding the molecular basis of protein/membrane interactions. Consequently, there is relatively little known about the structural mechanisms by which membrane-binding proteins might distinguish subtle variations in lipid membrane composition and/or structure. We have previously developed a multidisciplinary approach that combines molecular dynamics simulation with interfacial x-ray scattering experiments to produce an atomistic model for phosphatidylserine recognition by the immune receptor Tim4. However, this approach requires a previously determined protein crystal structure in a membrane-bound conformation. Tim1, a Tim4 homolog with distinct differences in both immunological function and sensitivity to membrane composition, was crystalized in a closed-loop conformation that is unlikely to support membrane binding. Here we have used a previously described highly mobile membrane mimetic membrane in combination with a conventional lipid bilayer model to generate a membrane-bound configuration of Tim1 in silico. This refined structure provided a significantly improved fit of experimental x-ray reflectivity data. Moreover, the coupling of the x-ray reflectivity analysis with both highly mobile membrane mimetic membranes and conventional lipid bilayer molecular dynamics simulations yielded a dynamic model of phosphatidylserine membrane recognition by Tim1 with atomic-level detail. In addition to providing, to our knowledge, new insights into the molecular mechanisms that distinguish the various Tim receptors, these results demonstrate that in silico membrane-binding simulations can remove the requirement that the existing crystal structure be in the membrane-bound conformation for effective x-ray reflectivity analysis. Consequently, this refined methodology has the potential for much broader applicability with respect to defining the atomistic details of membrane-binding proteins.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptor Celular 1 del Virus de la Hepatitis A
/
Membrana Dobles de Lípidos
Límite:
Animals
Idioma:
En
Revista:
Biophys J
Año:
2017
Tipo del documento:
Article
Pais de publicación:
Estados Unidos