EC Number   |
General Information |
Reference |
|---|
   7.6.2.8 | more |
molecular dynamics simulation of structure of the cobalamin-binding protein BtuF compared to Escherichia coli BtuF structure |
-, 749978 |
| 7.6.2.8 | more |
post-hydrolysis state of the vitamin B12 importer BtuCD by molecular dynamics (MD) simulations, overview. Predominantly asymmetric arrangement of the NBD dimer interface, with the ADP-bound site disrupted and the ATP-bound site preserved in most of the trajectories. TMDs response to ATP hydrolysis by separation of the L-loops and opening of the cytoplasmic gate II, indicating that hydrolysis of one ATP facilitates substrate translocation by opening the cytoplasmic end of translocation pathway. Motions of the L-loops and the cytoplasmic gate II are coupled with each other through a contiguous interaction network involving a conserved Asn83 on the extended stretch preceding transmembrane (TM)3 helix plus the cytoplasmic end of TM2/6/7 helix bundle. TMD-NBD communication mechanism for type II ABC importers. Besides the four basic domains of BtuCD, a cognate periplasmic binding protein, BtuF, is also required to maximize transport rate. Different conformational states of BtuCD, and mechanism of B12 transport cycle in BtuCD, overview. The occluded state of BtuCD, occ-BtuCD (PDB ID 4FI3), is regarded as a crucial step of the transport cycle, in which the transporter simultaneously loads the shipment B12 and the energy source ATPs. Transition from the occ-BtuCD state to the inward-facing state after ATP hydrolysis |
751956 |
| 7.6.2.8 | more |
the crystal structure of cobinamide-bound BtuF reveals a conformational change of a tryptophan residue W66 in the substrate binding cleft compared to the structure of cobalamin-bound BtuF, molecular dynamics simulations. BtuF is a class III periplasmic substrate binding protein |
752221 |
| 7.6.2.8 | more |
the homodimer BtuC spans the membrane and the two identical cytosolic ATPase domains BtuD form a sandwich dimer that couple chemical energy of two ATP molecules into structural changes of the full complex. A single substrate-binding protein (SBP) completes the transporter. The SBP belongs to cluster A or class III and exhibits relatively small conformational changes upon substrate binding. Modeling of the transport mechanism of BtuCD-F transporters embedded in lipid bilayers at the single molecule level, overview |
751661 |
| 7.6.2.8 | physiological function |
ABCD4 is a transporter of cobalamin and forms a complex with LMBD1 for the proper targeting or functioning, or both. The two proteins function as a complex |
752200 |
| 7.6.2.8 | physiological function |
ABCD4 is located on lysosomal membrane and is involved in the transport of vitamin B12 from lysosomes to the cytosol |
749821 |
| 7.6.2.8 | physiological function |
ATP-binding cassette (ABC) transporters are a large family of integral membrane proteins and involved in nutrient uptake, drug extrusion, and lipid homeostasis. They use the energy of ATP binding and hydrolysis to power substrate transport across the lipid bilayer. BtuCD-F is an ABC transporter that mediates cobalamin (Cbl) uptake into Escherichia coli, Escherichia coli is unable to synthesize Cbl de novo. BtuCD-F might also be involved in the uptake of cobinamide, a cobalamin precursor. Precursor cobinamide (Cbi) lacks the 5,6-dimethylbenzimidazole (DMB) moiety and sugar-phosphate linker and is therefore smaller than Cbl. BtuCD-catalyzed in vitro transport of cyano-cobinamide is ATP- and BtuF-dependent. BtuF residue W66 is important for high affinity Cbi binding, but not for substrate delivery or transport |
752221 |
| 7.6.2.8 | physiological function |
ATP-binding cassette (ABC) transporters form the largest class of active membrane transport proteins. Binding and hydrolysis of ATP by their highly conserved nucleotide-binding domains drive conformational changes of the complex that mediate transport of substrate across the membrane. The transporter complex of vitamin B12 importer BtuCD-F from Escherichia coli is consisting of a periplasmic soluble binding protein BtuF that binds the ligand and the transmembrane and ATPase domains BtuCD mediating translocation |
751661 |
| 7.6.2.8 | physiological function |
bacterial ABC importers catalyze the uptake of essential nutrients including transition metals and metal-containing cofactors |
752215 |
| 7.6.2.8 | physiological function |
cobalamin-specific ECF-type ABC transporter from Lactobacillus delbrueckii, ECF-CbrT, mediates the specific, ATP-dependent uptake of cobalamin. Cobalamin (vitamin B12) is the most complex B-type vitamin and is synthetized exclusively in a limited number of prokaryotes. Its biologically active variants contain rare organometallic bonds, which are used by enzymes in a variety of central metabolic pathways such as L-methionine synthesis and ribonucleotide reduction. Enzyme ECF-CbrT catalyzes ATP-dependent transport of cobalamin and cobinamide |
-, 750412 |
