Activating Compound | Comment | Organism | Structure |
---|---|---|---|
GluBP regulator | the GluTR regulator, GluTR binding protein (GluBP), spatially organizes tetrapyrrole synthesis by distributing enzyme GluTR into different suborganellar locations. GluBP belongs to a heme-binding family involved in heme metabolism. Complex structure of GluTR-GluBP from Arabidopsis thaliana, overview. The dimeric GluBP binds symmetrically to the catalytic domains of the V-shaped GluTR dimer via its C-terminal domain. A substantial conformational change of the GluTR NADPH-binding domain is observed, confirming the postulated rotation of the NADPH-binding domain for hydride transfer from NADPH to the substrate. Arg146, guarding the door for metabolic channeling, adopts alternative conformations, which may represent steps involved in substrate recognition and product release. GluBP stimulates GluTR catalytic efficiency with an approximate 3fold increase of the 5-aminolevulinic acid formation rate. Tunnel formation in the GluTR-GluBP complex for release of product L-glutamate 1-semialdehyde. GluBP stimulates GluTR activity and regulates GSA release | Arabidopsis thaliana |
Crystallization (Comment) | Organism |
---|---|
purified GluTR in complex with GluBP, X-ray diffraction structure determination and analysis at 2.8 A resolution, modeling | Arabidopsis thaliana |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
heme | feedback inhibition, GluTR activity can be inhibited by heme in a concentration-dependent way regardless of the presence of GluTR binding protein, GluBP | Arabidopsis thaliana |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-glutamyl-tRNAGlu + NADPH + H+ | Arabidopsis thaliana | - |
L-glutamate 1-semialdehyde + NADP+ + tRNAGlu | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | P42804 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-glutamyl-tRNAGlu + NADPH + H+ | - |
Arabidopsis thaliana | L-glutamate 1-semialdehyde + NADP+ + tRNAGlu | - |
? | |
additional information | GluTR employs hydride transfer from NADPH to the thioester-bound glutamate to produce glutamate-1-semialdehyde. The close contact between the nicotinamide ring of NADPH and the nucleophile Cys144 allows the transfer of hydride from NADPH to the thioester-bound glutamate. Tunnel formation in the GluTR-GluBP complex for release of product L-glutamate 1-semialdehyde | Arabidopsis thaliana | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
GluTR | - |
Arabidopsis thaliana |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NADP+ | - |
Arabidopsis thaliana | |
NADPH | NADPH-binding model of GluTR by using the homologous structure of a NADP-binding domain | Arabidopsis thaliana |
General Information | Comment | Organism |
---|---|---|
physiological function | GluTR-catalyzed reaction is the rate-limiting step of tetrapyrrole biosynthesis, and GluTR is the target of multiple posttranslational regulations, such as heme feedback inhibition, for the tetrapyrrole biosynthetic pathway. GluBP stimulates GluTR activity and regulates glutamate 1-semialdehyde release | Arabidopsis thaliana |