Table 2. The membrane topology prediction methods used in the current study.

Topology predictor	Algorithm	Reference
TMHMM 2.0	HMM	Krogh et al. (2001)
HMMTOP	HMM	Tusnady & Simon (2001)
PHOBIUS	HMM	Kall, Krogh & Sonnhammer (2004)
S-TMHMM	HMM	Viklund & Elofsson (2004)
TOPPRED	Hydrophobicity profiles	Vonheijne (1992)
SCAMPI-single	Hydrophobicity + Model	Bernsel et al. (2008)
MEMSAT 1.0	ANN + Grammer	Jones Taylor & Thorton (1994)