TABLE 4.
Consensus sequences of conserved motifs in transporters of the MFS, SMR, and RND families
| Motif | Consensus sequencea | Location |
|---|---|---|
| MFS, both 12- and 14-TMS cluster | ||
| A | G x L a D r x G r k x x (x) l | Loop between TMS 2 and 3 |
| B | l x x x R x x q G x g a a | TMS 4 |
| C | g x x x G P x x G G x l | End of TMS 5 |
| MFS, 12-TMS cluster | ||
| D2 | l g x x x x x P v x P | End of TMS 1 |
| G | G x x x G P L | End of TMS 11 |
| MFS, 14-TMS cluster | ||
| D1 | l D x T v x n v A l P | End of TMS 1 |
| E | D x x G x x L | TMS 7 |
| F | l g x x x G x a v x g x l | TMS 13 |
| H | W x w x F l l N v P i g | TMS 6 |
| SMR family | ||
| A | W i x l v i A i l l E V | TMS 1 |
| B | K x s e G F t r l x P S | Loop between TMS 1 and 2 |
| C | P v G t A Y A v W t G l G | Start of TMS 3 |
| RND family | ||
| A | G x s x v T v x F x x g t D x x x A q v q V q n k L q x A x p x L P x x V q x q g x x v x k | Loop between TMS 1 and 2 |
| B | a l v l s a V F l P m a f f g G x t G x i y r q f s i T x v s A m a l S v x v a l t l t P A l c A | TMS 6 |
| C | x x x G k x l x e A x x x a a x x R L R P l L M T s L a f i l G v l P l a i a t G x A G a | TMS 11 |
| D | S i N t l T l f g l v l a i G L l v D D A l V v V E N v e R v l a e | TMS 4 |
a
The motifs were identified by alignment of amino acid sequences (190, 191). The consensus sequences of the motifs are displayed as follows: x, any amino acid; capital letters, amino acid occurs in >70% of the examined sequences; lowercase letters, amino acid occurs in >40%; (x), amino acid not always present.