Major Facilitator Superfamily; The Major Facilitator Superfamily (MFS) is a large and diverse group of secondary transporters that includes uniporters, symporters, and antiporters. MFS proteins facilitate the transport across cytoplasmic or internal membranes of a variety of substrates including ions, sugar phosphates, drugs, neurotransmitters, nucleosides, amino acids, and peptides. They do so using the electrochemical potential of the transported substrates. Uniporters transport a single substrate, while symporters and antiporters transport two substrates in the same or in opposite directions, respectively, across membranes. MFS proteins are typically 400 to 600 amino acids in length, and the majority contain 12 transmembrane alpha helices (TMs) connected by hydrophilic loops. The N- and C-terminal halves of these proteins display weak similarity and may be the result of a gene duplication/fusion event. Based on kinetic studies and the structures of a few bacterial superfamily members, GlpT (glycerol-3-phosphate transporter), LacY (lactose permease), and EmrD (multidrug transporter), MFS proteins are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement. Bacterial members function primarily for nutrient uptake, and as drug-efflux pumps to confer antibiotic resistance. Some MFS proteins have medical significance in humans such as the glucose transporter Glut4, which is impaired in type II diabetes, and glucose-6-phosphate transporter (G6PT), which causes glycogen storage disease when mutated.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 6324411    1 MGLLAYIPTNVLATYLTLVLRSIGFTTFQANLLAIPNFVLHILLLFGLTWSTEKCNNRLGLSLLQPLYTVPLLAVLRFWK 80
Cdd:cd17327 241 FFFCSQITNNGISNFLPLILKSLGFYSLQTNLLSVPIGALGAVSLLIAALLSDRFKKRGLFAIFACVLALVGSIILLAAP 320

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 6324411   81 gtmFNKWGTYAIITLILDNPYIHAICVSLCSRNSQSVKTRTVSTCLYNMFVQAGLIISSNIYAKSDAPLYRKGNGVLFGL 160
Cdd:cd17327 321 ---NPPGAYFAAYILGGGSYAGFPILLSWISSNCAGYTKRATVLAIMLIFYNVGNIVAPQIFRAGDAPRYIPGNIALLVC 397

                ....*....
gi 6324411  161 ALFMFPILI 169
Cdd:cd17327 398 ACVSIVLSV 406

Pantothenate transporter FEN2 and similar transporters of the Major Facilitator Superfamily; This family is composed of Saccharomyces cerevisiae pantothenate transporter FEN2 (or fenpropimorph resistance protein 2) and similar proteins from fungi and bacteria including fungal vitamin H transporter, allantoate permease, and high-affinity nicotinic acid transporter, as well as Pseudomonas putida phthalate transporter and nicotinate degradation protein T (nicT). These proteins are involved in the uptake into the cell of specific substrates such as pathothenate, biotin, allantoate, and nicotinic acid, among others. The FEN2-like family belongs to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 6324411    1 MGLLAYIPTNVLATYLTLVLRSIGFTTFQANLLAIPNFVLHILLLFGLTWSTEKCNNRLGLSLLQPLYTVPLLAVLRFWK 80
Cdd:cd17327 241 FFFCSQITNNGISNFLPLILKSLGFYSLQTNLLSVPIGALGAVSLLIAALLSDRFKKRGLFAIFACVLALVGSIILLAAP 320

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 6324411   81 gtmFNKWGTYAIITLILDNPYIHAICVSLCSRNSQSVKTRTVSTCLYNMFVQAGLIISSNIYAKSDAPLYRKGNGVLFGL 160
Cdd:cd17327 321 ---NPPGAYFAAYILGGGSYAGFPILLSWISSNCAGYTKRATVLAIMLIFYNVGNIVAPQIFRAGDAPRYIPGNIALLVC 397

                ....*....
gi 6324411  161 ALFMFPILI 169
Cdd:cd17327 398 ACVSIVLSV 406

Pantothenate transporter FEN2 and similar transporters of the Major Facilitator Superfamily; This family is composed of Saccharomyces cerevisiae pantothenate transporter FEN2 (or fenpropimorph resistance protein 2) and similar proteins from fungi and bacteria including fungal vitamin H transporter, allantoate permease, and high-affinity nicotinic acid transporter, as well as Pseudomonas putida phthalate transporter and nicotinate degradation protein T (nicT). These proteins are involved in the uptake into the cell of specific substrates such as pathothenate, biotin, allantoate, and nicotinic acid, among others. The FEN2-like family belongs to the Major Facilitator Superfamily (MFS) of membrane transport proteins, which are thought to function through a single substrate binding site, alternating-access mechanism involving a rocker-switch type of movement.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 6324411    1 MGLLAYIPTNVLATYLTLVLRSIGFTTFQANLLAIPNFVLHILLLFGLTWSTEKCNNRLGLSLLQPLYTVPLLAVLRFWK 80
Cdd:cd17327 241 FFFCSQITNNGISNFLPLILKSLGFYSLQTNLLSVPIGALGAVSLLIAALLSDRFKKRGLFAIFACVLALVGSIILLAAP 320

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 6324411   81 gtmFNKWGTYAIITLILDNPYIHAICVSLCSRNSQSVKTRTVSTCLYNMFVQAGLIISSNIYAKSDAPLYRKGNGVLFGL 160
Cdd:cd17327 321 ---NPPGAYFAAYILGGGSYAGFPILLSWISSNCAGYTKRATVLAIMLIFYNVGNIVAPQIFRAGDAPRYIPGNIALLVC 397

                ....*....
gi 6324411  161 ALFMFPILI 169
Cdd:cd17327 398 ACVSIVLSV 406