EC Number   |
Natural Substrates |
|---|
   7.6.2.8 | ATP + H2O + cobinamide-[cobalamin-binding protein][side 1] |
- |
| 7.6.2.8 | ATP + H2O + cyanocobalamin-[cobalamin-binding protein][side 1] |
- |
| 7.6.2.8 | ATP + H2O + dicyanocobinamide-[cobalamin-binding protein][side 1] |
- |
| 7.6.2.8 | ATP + H2O + vitamin B12-[cobalamin-binding protein][side 1] |
- |
| 7.6.2.8 | ATP + H2O + vitamin B12/out |
- |
| 7.6.2.8 | more |
BtuCD alone or the BtuCD-F complex do not bind vitamin B12. Only free, uncomplexed BtuF binds vitamin B12 with high affinity. Upon binding of BtuF to BtuCD, vitamin B12 is released from BtuF and is only transiently associated with the complex |
| 7.6.2.8 | more |
BtuCD forms a stable complex with the vitamin B12 binding protein BtuF. Using protein docking and MD simulation studies it is shown that holo-BtuF stabilizes the open conformation of BtuCD, whereas the transporter begins to close again when BtuF or vitamin B12 is removed suggesting BtuCD-F is capable of substrate sensitivity. BtuC transmembrane helices 3 and 5, the L-loops and the adjacent helices comprised of BtuC residues 170-180 are identified as hotspots of conformational change |
| 7.6.2.8 | more |
BtuCD forms an extremely stable complex with the vitamin B12 binding protein BtuF. Vitamin B12 accelerates complex dissociation rate, with ATP having an additional destabilizing effecf |
| 7.6.2.8 | ATP + H2O + vitamin B12/out |
BtuCD is a type II ABC importer that catalyzes the translocation of vitamin B12 from the periplasm into the cytoplasm of Escherichia coli. BtuD is complexed with BtuC, a permease protein, and BtuF, a periplasmic binding protein, structure, overview |
| 7.6.2.8 | more |
BtuM binds vitamin B12 in its base-off conformation, in which the 5,6-dimethylbenzimidazole moiety does not bind to the cobalt ion, but with a cysteine residue as axial ligand of the corrin cobalt ion, BtuMTd binds cobalamin (Cbl) using cysteine ligation. In contrast, at physiological pH the conformation of free Cbl in aqueous solution is base-on with the 5,6-dimethylbenzimidazole moiety coordinated to the cobalt ion in the alpha-axial position |
