| Autor: |
ZALLOT, Rémi, YAZDANI, Mohammad, GOYER, Aymeric, ZIEMAK, Michael J., GUAN, Jiahn-Chou, MCCARTY, Donald R., DE CRÉCY-LAGARD, Valeéie, GERDES, Svetlana, GARRETTH, Timothy J., BENACH, Jordi, HUNT, John F., SHINTANI, David K., HANSON, Andrew D. |
| Předmět: |
|
| Zdroj: |
Biochemical Journal; 10/1/2014, Vol. 463 Issue 1, p145-155, 16p |
| Abstrakt: |
The TenA protein family occurs in prokaryotes, plants and fungi; it has two subfamilies, one (TenA_C) having an active-site cysteine, the other (TenA_E) not. TenA_C proteins participate in thiamin salvage by hydrolysing the thiamin breakdown product amino- HMP (4-amino-5-aminomethyl-2-methylpyrimidine) to HMP (4- amino-5-hydroxymethyl-2-methylpyrimidine); the function of TenA_E proteins is unknown. Comparative analysis of prokaryote and plant genomes predicted that (i) TenA_E has a salvage role similar to, but not identical with, that of TenA_C and (ii) that TenA_E and TenA_C also have non-salvage roles since they occur in organisms that cannot make thiamin. Recombinant Arabidopsis and maize TenA_E proteins (At3g16990, GRMZM2G080501) hydrolysed amino-HMP to HMP and, far more actively, hydrolysed the N-formyl derivative of amino-HMP to amino- HMP. Ablating the At3g16990 gene in a line with a null mutation in the HMP biosynthesis gene ThiC prevented its rescue by amino-HMP. Ablating At3g16990 in the wild-type increased sensitivity to paraquat-induced oxidative stress; HMP overcame this increased sensitivity. Furthermore, the expression of TenA_E and ThiC genes in Arabidopsis andmaizewas inversely correlated. These results indicate that TenA_E proteins mediate amidohydrolase and aminohydrolase steps in the salvage of thiamin breakdown products. As such products can be toxic, TenA_E proteins may also pre-empt toxicity. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
