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Stimulation of Nipah Fusion: Small Intradomain Changes Trigger Extensive Interdomain Rearrangements.

Abstract：

:Nipah is an emerging paramyxovirus that is of serious concern to human health. It invades host cells using two of its membrane proteins-G and F. G binds to host ephrins and this stimulates G to activate F. Upon activation, F mediates virus-host membrane fusion. Here we focus on mechanisms that underlie the stimulation of G by ephrins. Experiments show that G interacts with ephrin and F through separate sites located on two different domains, the receptor binding domain (RBD) and the F activation domain (FAD). No models explain this allosteric coupling. In fact, the analogous mechanisms in other paramyxoviruses also remain undetermined. The structural organization of G is such that allosteric coupling must involve at least one of the two interfaces-the RBD-FAD interface and/or the RBD-RBD interface. Here we examine using molecular dynamics the effect of ephrin binding on the RBD-RBD interface. We find that despite inducing small changes in individual RBDs, ephrin reorients the RBD-RBD interface extensively, and in a manner that will enhance solvent exposure of the FAD. While this finding supports a proposed model of G stimulation, we also find from additional simulations that ephrin induces a similar RBD-RBD reorientation in a stimulation-deficient G mutant, V209 VG → AAA. Together, our simulations suggest that while inter-RBD reorientation may be important, it is not, by itself, a sufficient condition for G stimulation. Additionally, we find that the mutation affects the conformational ensemble of RBD globally, including the RBD-FAD interface, suggesting the latter's role in G stimulation. Because ephrin induces small changes in individual RBDs, a proper analysis of conformational ensembles required that they are compared directly-we employ a method we developed recently, which we now release at SimTK, and show that it also performs excellently for non-Gaussian distributions.

journal_name

Biophys J

journal_title

Biophysical journal

authors

Dutta P,Siddiqui A,Botlani M,Varma S

doi

10.1016/j.bpj.2016.09.002

subject

Has Abstract

pub_date

2016-10-18 00:00:00

pages

1621-1630

issue

eissn

0006-3495

issn

1542-0086

pii

S0006-3495(16)30766-4

journal_volume

111

pub_type

杂志文章

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Stimulation of Nipah Fusion: Small Intradomain Changes Trigger Extensive Interdomain Rearrangements.