Structural Basis for the Recognition of Cellular mRNA Export Factor REF by Herpes Viral Proteins HSV-1 ICP27 and HVS ORF57
Figure 5
Modelling of complex between human Aly and HSV-ICP27.
(A) Sequence alignment of RRM domains of murine REF2-I (mREF2-I: CAB76384) used in this study, murine Aly (mALY: AAC53117) and human Aly (hALY: AAD09608). Position of secondary structure elements (β-sheets, α-helices and loops) is shown in relation to the REF2-I. Resides in mALY and mREF2-I that differ from hALY are highlighted in light red. (B) A cartoon of the structure of REF-ICP27 with the position of the 7 amino acid differences indicated using red space-fill spheres, this orientation shown is the same as used in Fig. 3, whereas in (C) an alternative orientation is used for clarity. Only one amino acid difference is part of the ICP27 interaction site, namely Val138 of mREF2-I, which is a Phe in hALY. (D) A model of hsALY (blue) overlaid with the experimental structure of mREF2-I (green), with ICP27 also shown (orange). Residues that differ between the RRM domains of mREF2-I and hsALY are red sticks in the mREF2-I form and cyan sticks in hsALY. The sidechain of M145 altered in the modelling procedure is indicated by sticks. Also the ICP27 sidechain of L108 is indicated (orange) which is positioned within the hydrophobic pocket of REF. (E) Detailed view of the sidechains of Met 145, and Val138 and Phe138 in the modelled hsALY (blue) and experimental REF2-I (green) structures, plus L108 of ICP27 is shown (orange).