TABLE 2

Distribution of lipid-facing (out) and non-lipid-facing (in) amino acid residues in transmembrane helices The oligomeric structure (Table 1) of each protein was viewed. Residues exposed to the surface of the protein within the transmembrane domains were considered lipid-facing (out) and those buried between helices were considered non-lipid-facing (in). The numbers of each residue were counted.

Protein G A P V L I M C F Y W H K R E D Q N T S Total Residues
Rho in 6 14 5 11 9 6 7 4 7 3 1 1 1 1 4 1 0 6 7 3 97
Rho out 4 5 4 10 14 14 5 0 14 8 2 2 0 1 1 0 2 1 5 2 94
Kv1.2K+ ina 4 7 2 7 2 6 1 2 4 0 2 0 2 2 4 1 0 0 3 4 53
Kv1.2K+ outa 1 2 1 4 13 7 1 0 9 1 1 0 0 4 0 1 0 0 1 1 47
AQP0 in 12 22 5 12 15 1 1 1 9 7 0 2 0 2 2 2 5 2 7 6 113
AQP0 out 3 3 0 7 12 6 1 2 7 1 3 0 0 1 0 0 0 0 1 2 49
ATPase in 6 14 4 14 17 13 5 3 2 1 2 1 3 2 7 3 5 8 4 10 124
ATPase out 6 6 1 9 22 10 2 1 8 1 6 0 3 3 3 1 3 0 3 2 90
LTC4S in 4 10 3 5 8 1 0 1 3 5 1 0 0 3 1 0 2 0 2 3 52
LTC4S out 2 8 0 4 15 1 0 1 3 2 1 0 0 3 0 0 2 0 0 2 44
FLAP in 3 6 1 7 2 0 1 0 0 5 1 0 0 1 0 1 2 3 3 3 39
FLAP out 3 4 1 6 8 4 1 1 8 0 0 1 3 1 1 0 1 1 0 0 44
Total in 35 73 20 56 53 27 15 11 25 21 7 4 6 11 18 8 14 19 26 29 478
Total out 19 28 7 40 84 42 10 5 49 13 13 3 6 13 5 2 8 2 10 9 368
  • Rho, bovine rhodopsin; AQP, bovine aquaporin 0; ATPase, rabbit Ca2+-APTase

  • a S1 and S3 transmembrane helices are poly-Ala chains in the crystal structure so they were excluded from analysis; the molecule was analyzed as a tetramer