Introduction - This script shows the structure of HbS. Scroll down until the text corresponding to the view is visible. (based on 1hbs.pdb, E.A.Padlan & W.E.Lowe, J. Biol. Chem. 260 8272 (1985)).
Here we see a β subunit of HbS with Val6 on the surface.
Here is a complex between two β subunits of different HbS tetramers. They are held together by Val6.
In this view we have sliced through the complex to show how Val6 joins the two subunits together.