Figure 12.

Example of a swivel-type kink. A swivel-type kink in proline-containing (P123) TM4 helix of lactose permease (PDB:1PV6), where N- and C-terminal halves of the helical face with the largest probe-accessible area are rotated by ~80 at residue Asn119 relative to the axis connecting the N- and C-termini of the helix. (A) Side view. (B) Arrows show that orientation of the mostly lipid-accessible helical face is different in the N-terminaland C-terminal regions of the helix.