Figure 1.

Contact map of helix-helix interactions within the left-handed helical pair formed by helices tm I and tm II from SdhC subunit of E. coli succinate dehydrogenase (PDB: 1NEK). The three top rows and three left columns contain information on coiled coil heptad positions abcdefg (marked as H), residue numbers (N) and residue types (R) for tm I and tm II, respectively. Residues involved into interhelical interactions between these two TM helices are in bold. The number of atomic contacts as determined by INTERFACE calculations with probe radius of 0.5 Å between two interacting residues is listed at the intersections of the respective row and column. For example, Ser33 from tm I has 4 atomic contacts with Ala80, 3 atomic contacts with Tyr83, and 8 atomic contacts with His84 from tm II, while neighboring residue Val32 has no contacts with any residue from tm I.