Glutamate-1-semialdehyde 2,1-Aminomutase from Thermosynechococcus elongatusGlutamate-1-semialdehyde 2,1-Aminomutase from Thermosynechococcus elongatus

Structural highlights

2cfb is a 1 chain structure with sequence from Synechococcus elongatus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.85Å
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GSA_THEVB

Evolutionary Conservation

 

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Glutamate-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.

Evolutionary relationship between initial enzymes of tetrapyrrole biosynthesis.,Schulze JO, Schubert WD, Moser J, Jahn D, Heinz DW J Mol Biol. 2006 May 19;358(5):1212-20. Epub 2006 Mar 10. PMID:16564539[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Schulze JO, Schubert WD, Moser J, Jahn D, Heinz DW. Evolutionary relationship between initial enzymes of tetrapyrrole biosynthesis. J Mol Biol. 2006 May 19;358(5):1212-20. Epub 2006 Mar 10. PMID:16564539 doi:10.1016/j.jmb.2006.02.064

2cfb, resolution 2.85Å

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