5che
From Proteopedia
Crystal structure of Arabidopsis glutamyl-tRNA reductase in complex with its regulatory proteins
Structural highlights
Function[HEM11_ARATH] Catalyzes the NADPH-dependent reduction of glutamyl-tRNA(Glu) to glutamate 1-semialdehyde (GSA). Probably involved in the tetrapyrrole synthesis required for the chlorophyll biosynthesis.[1] [2] [FLU_ARATH] Negative regulator of tetrapyrrole biosynthesis (including chlorophyll) in chloroplasts, probably via HEMA1 repression. Inhibits especially the magnesium ion Mg(2+) branch of tetrapyrrole biosynthesis, but independently of heme.[3] [4] [5] [6] [GLUBP_ARATH] Involved in the regulation of glutamyl-tRNA reductase (GluTR) which is important for the synthesis and distribution of 5-aminolevulinate, a precursor in heme and chlorophyll biosynthesis (PubMed:22180625). Stimulates GluTR activity and regulates glutamate-1-semialdehyde release. May play a role in heme metabolism (PubMed:24753615). Necessary for efficient photosynthetic electron transport in chloroplasts (PubMed:20657737). Publication Abstract from PubMedTetrapyrrole biosynthesis is an essential and tightly regulated process, and glutamyl-tRNA reductase (GluTR) is a key target for multiple regulatory factors at the post-translational level. By binding to the thylakoid membrane protein FLUORESCENT (FLU) or the soluble stromal GluTR-binding protein (GBP), the activity of GluTR is down- or up-regulated. Here, we reconstructed a ternary complex composed of the C-terminal tetratricopepetide-repeat domain of FLU, GBP, and GluTR, crystallized and solved the structure of the complex at 3.2 A. The overall structure resembles the shape of merged two binary complexes as previously reported, and shows a large conformational change within GluTR. We also demonstrated that GluTR binds tightly with GBP but does not bind to GSAM under the same condition. These findings allow us to suggest a biological role of the ternary complex for the regulation of plant GluTR. The Arabidopsis glutamyl-tRNA reductase (GluTR) forms a ternary complex with FLU and GluTR-binding protein.,Fang Y, Zhao S, Zhang F, Zhao A, Zhang W, Zhang M, Liu L Sci Rep. 2016 Jan 22;6:19756. doi: 10.1038/srep19756. PMID:26794057[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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