ABC Superfamily

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The ABC Superfamily stands for ATP Binding Cassette Family. These proteins are invloved in ion transport across the membrane, with members including CFTR AND P-Glycoprotein. The standard structure of a member of the ABC is 12 membrane-spanning domains and 2 Nucleotide Binding Domains (occassionally referred to as a Nucleotide Folding Domain). ATP binds at the NBD [1].

The ABC family of proteins are one of the largest family of proteins known and have been found in both prokaryotes and eukaryotes. This family of proteins differ significantly from other ATP-binding protein family of kinases. They are not all involved in ion transport across the membrane, some have also been found to be involved in the presentation of antigens as well as being involved in different inherited human diseases.

ABC superfamily structure

ABC transport can be found in bacteria and human cell memberane with different substrate. These protein is first defined by bacteria [2]. All the plasmid cell membrane use the ion concentration gradient channel for nutrients entry or out to the cell enviroment across the lipid bilayers. There are 4 domains linked in the cell membrane protein which are 2 complex nucleotide binding domains (NBDS) and two primary prtein fold transmembrane domains (TMDS) [3]. These domains are found in both prokaryotes cell and eukaryotes cells [4].

However, bacteria also contain energy of ATP activate substrate [5].

Most important mutation cause in the genome.Using drug resistance is one of the major process for the treatment. Agonist or antagoints drugs are all bind to the enzymes and protein on the surface of the cell membrance through the ABC transport by a specific subfamily. Different substrate comes with different subunit or different mechanism in same subunits [6].

Disease

Single change of the mechanism in the cell can cause different effect. Abnormal function of the membrance cause different dieases. Cystic Fibrosis is one of the gene mutation which occurs in detaF508 in 75% of the patients [7].

ABC ion channel is passive transport in the cell membrane. There are 3 different domains precented. The transmembrane demains which forms pore in the cell membrane.

Regulatary domains (R domains) has the same function with nucleotide binding domains (NBD) use for the gateing of the ion channels [8].

References

  1. Rees, D.C.; E. Johnson; O. Lewinson. 2009. ABC transporters: the power to change. Nat. Rev. Mol. Cell Biol. 10, 218-227.
  2. The cell
  3. Wen PC, Tajkhorshid E.Biophys j.,Conformational coupling of the nucleotide-binding and the transmembrane domains in ABC transporters.101(3):680-90
  4. Zolnerciks JK, Andress EJ, Nicolaou M, Linton KJ Structure of ABC transporters.50(1):43-61.
  5. Gyimesi G, Ramachandran S, Kota P, Dokholyan NV, Sarkadi B, Hegedűs T, Biochim Biophys Acta.,ATP hydrolysis at one of the two sites in ABC transporters initiates transport related conformational transitions.1808(12):2954-2964
  6. Dębska S, Owecka A, Czernek U, Szydłowska-Pazera K, Habib M, Potemski P Transmembrance transporters ABCC 19;65:552-61.
  7. Rosenberg MF, O'Ryan L, Hughes G, Zhao Z, Aleksandrov L, Riordan JR, Ford RC , J Biol Chem. The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR):3D structure and localisation of a channel gate.
  8. Rowe,S M Miller,S and Sorcher, EJ. (2005) Mechanisms of Disease: cystic fibrosis New England Journal of Medicine. 352(19),2005, p. 1992-2001

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