EC Number   |
General Information |
Reference |
|---|
   2.7.1.180 | evolution |
ApbE is a member of a family of flavin transferases that incorporates flavin mononucleotide (FMN) to subunits of diverse respiratory complexes, which fulfill important homeostatic functions. Enzyme residue His257 is absolutely conserved in the family |
762233 |
| 2.7.1.180 | evolution |
FMN residue attached through a phosphoester bond is found in three types of protein architectures-prokaryotic FMN bind and NQR2 RnfD RnfE (PF03116) domains and an about 50-residue N-terminal extension of the ApbE domain in eukaryotic NADH:fumarate oxidoreductases. These three architectures are non-homologous, and their sequences have nothing in common, except for a short motif around the flavinylated residue. The motif common to all three flavinylated architectures can be depicted as Dxx(s/t)(g/s)At/s, where the last residue is the flavin acceptor. It is threonine in all characterized proteins of the first two groups, but it is sporadically replaced by serine in 3.5-5% of their putative homologues |
761101 |
| 2.7.1.180 | evolution |
there likely are two classes of Ftps, one associated with FAD-binding and the other with FAD hydrolysis |
-, 757628 |
| 2.7.1.180 | malfunction |
a single amino acid substitution converts it from an FAD-binding protein to a Mg2+-dependent FAD diphosphatase (Ftp_Tp-like, EC 3.6.1.18) |
757628 |
| 2.7.1.180 | malfunction |
a single amino acid substitution Y60N converts it from an FAD-binding protein to a Mg2+-dependent FAD diphosphatase (Ftp_Tp-like). The engineered protein variant (Ftp_EcY60A) shows Mg2+-dependent FAD diphosphatase activity, but also retains its Mg2+-dependent FMN transferase (EC 2.7.1.180) activity on the protein substrate, indicating that the protein variant enzyme has dual activity |
757628 |
| 2.7.1.180 | malfunction |
enzyme inactivation results in a complete loss of the quinone reductase activity of Na+-translocating NADH:quinone oxidoreductase |
-, 725516 |
| 2.7.1.180 | malfunction |
lesion in the ApbE1 gene in results in inactive Na+-translocating NADH:quinone oxidoreductase, but cytoplasmic fumarate reductase activity remains unchanged |
-, 724473 |
| 2.7.1.180 | malfunction |
lesion in the ApbE2 gene in results in inactive cytoplasmic fumarate reductase, but Na+-translocating NADH:quinone oxidoreductase activity remains unchanged |
-, 724473 |
| 2.7.1.180 | malfunction |
the replacement of the flavin acceptor threonine with alanine completely abolishes the modification reaction, whereas the replacements of conserved aspartate and serine had only minor effects. Effects of other substitutions, including replacing the acceptor threonine with serine, (a 10-55% decrease in the flavinylation degree). Replacements of conserved leucine and threonine residues in the binding pocket that accommodates FMN residue still allows appreciable flavinylation of the NqrC subunit of Vibrio harveyi Na+-translocating NADH:quinone oxidoreductase, despite a profound weakening of the isoalloxazine ring binding and an increase in its exposure to solvent |
761101 |
| 2.7.1.180 | more |
residue His257 is located in the catalytic site and the mutational substitution does not produce major conformational changes |
761498 |
