Seeing HPV in the New Light Offers a Glimpse of Heparin.

In this issue of Structure, Guan et al. (2017) describe cryo-EM mapping of human papillomavirus 16 (HPV16) capsids that propose locations for L2 and heparin binding sites. The high resolution of the modern cryo-EM methods (in this case down to 4.3 Å) opens great opportunities to probe conformational changes that take place during virus-receptor binding.