ATP-binding cassette (ABC) transporters constitute a ubiquitous superfamily of integral membrane proteins that are responsible for the ATP-powered translocation of many substrates across membranes. ABC transporters have a characteristic architecture that consists minimally of four domains: two ABC domains (or nucleotide-binding domains) with highly conserved sequence motifs and two transmembrane domains (TMDs). Additional domains can be fused to these core elements to confer regulatory functions, and a periplasmic binding protein is required for ligand delivery to prokaryotic importer members of this family. Similarities in the structure of the ABC domains structure support a common mechanism by which ABC transporters, both importers and exporters, orchestrate a series of nucleotide- and substrate-dependent conformational changes that result in substrate translocation across the membrane. TMDs are structurally heterogeneous, and three distinct sets of folds have been recognized. Although the detailed folds vary, they all interact with the helical domains of the ABCs through 'coupling helices', which are located in the loops between membrane-spanning helices. These interactions connect the conformations of the TMDs to the nucleotide state of the ABC domains. Here you can see a bottom view of the NosDFY ABC transporter from Pseudomonas sturtzeri determined by cryoEM. The ribbon model represents the structure of a helper protein (NosD) that modulates the activity of the ABC transporter (PDB code: 7O0Y)
#molecularart ... #immolecular ... #ABC .... #transporter ... #membrane ... #pseudomonas ... #NosDYF ... #binding ... #energy ... #ATP ... #cryoem
Structure of the NosDYF transporter rendered with @proteinimaging and finally composed with @corelphotopaint
#molecularart ... #immolecular ... #ABC .... #transporter ... #membrane ... #pseudomonas ... #NosDYF ... #binding ... #energy ... #ATP ... #cryoem
Structure of the NosDYF transporter rendered with @proteinimaging and finally composed with @corelphotopaint
