Other energetically unfavorable helical disruptions, are counteracted by internal hydrogen bonding between surrounding residues. Further bends or kinks are induced through Gly-Gly, Pro-Pro, or Gly-Pro segments, ensuring that the helical structure is disrupted. In general, the calculated tilt angle for each transmembrane helix (H) is 22 12?(Nyholm et al., 2007). In rhodopsin, the strongest helical