Six-transmembrane helical domain of the ATP-binding cassette transporters; This family represents a subunit of six transmembrane (TM) helices typically found in the ATP-binding cassette (ABC) transporters that function as exporters, which contain 6 TM helices per subunit (domain), or a total of 12 TM helices for the complete transporter. The ABC exporters are found in both prokaryotes and eukaryotes, where they mediate the cellular secretion of toxic compounds and a various type of lipids. In addition to ABC exporters, ABC transporters include two classes of ABC importers, classified depending on details of their architecture and mechanism. Only the ABC exporters are included in this family. ABC transporters typically consist of two transmembrane domains (TMDs) and two nucleotide-binding domains (NBDs). The sequences and structures of the TMDs are quite varied between the different type of transporters, suggesting chemical diversity of the translocated substrates, whereas NBDs are conserved among all ABC transporters. The two NBDs together bind and hydrolyze ATP, thereby providing the driving force for transport, while the TMDs participate in substrate recognition and translocation across the lipid membrane. However, some ABC genes are organized as half-transporters, which must form either homodimers or heterodimers to form a functional unit. The ABC exporters play a role in multidrug resistance to antibiotics and anticancer agents, and mutations in these proteins have been shown to cause severe human diseases such as cystic fibrosis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2041465566   3 SWGLAFLALVTYALLAIAIPNQFAQQLQPFLKEQNASRKGYVSYFIESLKSMKDLMQFQQTDARFANLTQKSQEVNGQER 82
Cdd:cd18585   134 SPALALILLAGLLLAGVVIPLLFYRLGKKIGQQLVQLRAELRTELVDGLQGMAELLIFGALERQRQQLEQLSDALIKEQR 213

                  ...
gi 2041465566  83 RVA 85
Cdd:cd18585   214 RLA 216

Six-transmembrane helical domain (6-TMD) of the CydC, a component of the ABC cysteine/GSH transporter; The CydC protein, together with the CydD protein, constitutes a bacterial heterodimeric ATP-binding cassette (ABC) transporter complex required for formation of the functional cytochrome bd oxidase in both gram-positive and gram-negative aerobic bacteria. In Escherichia coli, the biogenesis of both cytochrome bd-type quinol oxidases and periplasmic cytochromes requires the ABC-type cysteine/GSH transporter CydDC, which exports cysteine and glutathione from the cytoplasm to the periplasm to maintain redox homeostasis. The CydDC forms a heterodimeric ABC transporter with two transmembrane domains (TMDs), each predicted to comprise six TM alpha-helices and two nucleotide binding domains (NBDs).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2041465566   3 SWGLAFLALVTYALLAIAIPNQFAQQLQPFLKEQNASRKGYVSYFIESLKSMKDLMQFQQTDARFANLTQKSQEVNGQER 82
Cdd:cd18585   134 SPALALILLAGLLLAGVVIPLLFYRLGKKIGQQLVQLRAELRTELVDGLQGMAELLIFGALERQRQQLEQLSDALIKEQR 213

                  ...
gi 2041465566  83 RVA 85
Cdd:cd18585   214 RLA 216

Six-transmembrane helical domain (6-TMD) of the CydC, a component of the ABC cysteine/GSH transporter; The CydC protein, together with the CydD protein, constitutes a bacterial heterodimeric ATP-binding cassette (ABC) transporter complex required for formation of the functional cytochrome bd oxidase in both gram-positive and gram-negative aerobic bacteria. In Escherichia coli, the biogenesis of both cytochrome bd-type quinol oxidases and periplasmic cytochromes requires the ABC-type cysteine/GSH transporter CydDC, which exports cysteine and glutathione from the cytoplasm to the periplasm to maintain redox homeostasis. The CydDC forms a heterodimeric ABC transporter with two transmembrane domains (TMDs), each predicted to comprise six TM alpha-helices and two nucleotide binding domains (NBDs).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2041465566   3 SWGLAFLALVTYALLAIAIPNQFAQQLQPFLKEQNASRKGYVSYFIESLKSMKDLMQFQQTDARFANLTQKSQEVNGQER 82
Cdd:cd18585   134 SPALALILLAGLLLAGVVIPLLFYRLGKKIGQQLVQLRAELRTELVDGLQGMAELLIFGALERQRQQLEQLSDALIKEQR 213

                  ...
gi 2041465566  83 RVA 85
Cdd:cd18585   214 RLA 216