Evolutionary relationship between initial enzymes of tetrapyrrole biosynthesis.
Cast your vote
You can rate an item by clicking the amount of stars they wish to award to this item.
When enough users have cast their vote on this item, the average rating will also be shown.
Your vote was cast
Thank you for your feedback
Thank you for your feedback
MetadataShow full item record
AbstractGlutamate-1-semialdehyde 2,1-aminomutase (GSAM) is the second enzyme in the C(5) pathway of tetrapyrrole biosynthesis found in most bacteria, in archaea and in plants. It catalyzes the transamination of glutamate-1-semialdehyde to 5-aminolevulinic acid (ALA) in a pyridoxal 5'-phosphate (PLP)-dependent manner. We present the crystal structure of GSAM from the thermophilic cyanobacterium Thermosynechococcus elongatus (GSAM(Tel)) in its PLP-bound form at 2.85A resolution. GSAM(Tel) is a symmetric homodimer, whereas GSAM from Synechococcus (GSAM(Syn)) has been described as asymmetric. The symmetry of GSAM(Tel) thus challenges the previously proposed negative cooperativity between monomers of this enzyme. Furthermore, GSAM(Tel) reveals an extensive flexible region at the interface of the proposed complex of GSAM with glutamyl-tRNA reductase (GluTR), the preceding enzyme in tetrapyrrole biosynthesis. Compared to GSAM(Syn), the monomers of GSAM(Tel) are rotated away from each other along the dimerization interface by 10 degrees . The associated flexibility of GSAM may be essential for complex formation with GluTR to occur. Unexpectedly, we find that GSAM is structurally related to 5-aminolevulinate synthase (ALAS), the ALA-producing enzyme in the Shemin pathway of alpha-proteobacteria and non-plant eukaryotes. This structural relationship applies also to the corresponding subfamilies of PLP-dependent enzymes. We thus propose that the CoA-subfamily (including ALAS) and the aminotransferase subfamily II (including GSAM) are evolutionarily closely related and that ALAS may thus have evolved from GSAM.
CitationJ. Mol. Biol. 2006, 358(5):1212-20
- Crystal structure of glutamate-1-semialdehyde aminotransferase from Bacillus subtilis with bound pyridoxamine-5'-phosphate.
- Authors: Ge H, Lv X, Fan J, Gao Y, Teng M, Niu L
- Issue date: 2010 Nov 12
- Complex formation between glutamyl-tRNA reductase and glutamate-1-semialdehyde 2,1-aminomutase in Escherichia coli during the initial reactions of porphyrin biosynthesis.
- Authors: Lüer C, Schauer S, Möbius K, Schulze J, Schubert WD, Heinz DW, Jahn D, Moser J
- Issue date: 2005 May 13
- Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase from Arabidopsis thaliana.
- Authors: Song Y, Pu H, Jiang T, Zhang L, Ouyang M
- Issue date: 2016 Jun
- Structure and function of glutamyl-tRNA reductase involved in 5-aminolaevulinic acid formation.
- Authors: Moser J, Schubert WD, Heinz DW, Jahn D
- Issue date: 2002 Aug
- V-shaped structure of glutamyl-tRNA reductase, the first enzyme of tRNA-dependent tetrapyrrole biosynthesis.
- Authors: Moser J, Schubert WD, Beier V, Bringemeier I, Jahn D, Heinz DW
- Issue date: 2001 Dec 3