Table 1. Transmembrane Proteins Analyzed in This Work Belong to Different Structural Types and Approximate Symmetry Groups.
| protein | PDB ID code | residues | approximate symmetry point group | number of modular repeats | structure type |
|---|---|---|---|---|---|
| human integral membrane protein (hIMP) TMEM14A | 2LOP(75) | 25–99 | C3 | 3 | α-helical bundle |
| transmembrane domain of N-acetylcholine receptor (nAChR) β2 subunit | 2KSR(76) | 25–164 | C4 | 4 | α-helical bundle |
| human water channel aquaporin-1 (AQP1) | 1H6I(77) | 9–233 | S2 (=Ci) | 8 | α-helical bundle |
| mitochondrial ADP/ATP carrier | 1OKC(78) | 2–293 | C3 | 9 | α-helical bundle |
| ammonia transporter (AMT1) | 2B2F(79) | 1–391 | S2 (=Ci) | 11 | α-helical bundle |
| cytochrome c oxidase subunit 1 (COX1)-β | 1QLE(80) | 17–554 | C3 | 12 | α-helical bundle |
| outer membrane protein X (OmpX) | 1Q9F(81) | 1–148 | C4 | 8 | β-barrel |
| outer membrane protein A (OmpA) | 2GE4(82) | 0–176 | C4 | 8 | β-barrel |