Fig. 2: Interaction of 627-NLS and ANP32A observed from the perspective of 627-NLS. | Nature Communications

Fig. 2: Interaction of 627-NLS and ANP32A observed from the perspective of 627-NLS.

From: Molecular basis of host-adaptation interactions between influenza virus polymerase PB2 subunit and ANP32A

Fig. 2

a Representation of the domains of 627-NLS. The C-terminal domains of PB2 comprise two sub-domains (627—orange and NLS—grey) connected by a linker (red) and terminated by an NLS peptide (NLS). The molecule exists in equilibrium between closed and open forms that exchange at 50 s−1 at room temperature. The position of the E627K adative mutation is shown in blue. b HSQC of the open-only form of 2D, 13C and 15N-labelled 627-NLS(K) (D730A/E687A; 200 μM; red), indicating chemical shifts of selected sites upon addition of hANP32A IDD (400 μM blue). c CSP of 627-NLS(K) (300 μM) upon addition of hANP32A IDD at a ratio of 1:4 (red) and 627-NLS(E) (300 μM) upon addition of avANP32A IDD at a ratio of 1:4 (blue). Spectra recorded on 2D, 13C and 15N-labelled 627-NLS at 293 K and 850 MHz. Only shifts affecting resonances corresponding to the open form are shown for clarity. d CSP of 627-NLS(K) (red) induced by addition of hANP32A derived from b above the threshold of 0.25 (dashed line) for 627 (grey) and NLS (yellow) domains. Two orientations of the protein are shown. e Distribution of basic sidechains (blue) on the surface of the 627 and NLS domains. By comparison with c, it is evident that one of the two faces preferentially interacts with the IDD. f Represention of the largest differential shifts on the surface of the 627 domain upon addition of ANP32A as shown in c. Amino acids showing the largest difference in CSP (>0.15) in the 627-NLS(K):hANP32A IDD complex compared to the 627-NLS(E):avANP32A IDD are highlighted in red (position of 627 shown in blue). g Interaction of full-length 627-NLS with ANP32A induces a change in the open-closed equilibrium. Red—peaks reporting on the open and closed forms of 627-NLS(E) or 627-NLS(K) before the addition (blue) of h or avANP32A, respectively. The interaction with ANP32A potentiates the equilibrium in both cases, fully removing the closed form in the case of the avian pair. Residues distal from the main interaction site were chosen to reduce the risk of peak disappearance due to direct interaction.

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