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Crystal structure of the conserved hypothetical protein APE0931 from Aeropyrum pernix K1
Structural highlights
FunctionDPHB_AERPE S-adenosyl-L-methionine-dependent methyltransferase that catalyzes the trimethylation of the amino group of the modified target histidine residue in translation elongation factor 2 (EF-2), to form an intermediate called diphthine. The three successive methylation reactions represent the second step of diphthamide biosynthesis (By similarity). 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 PubMedThe target of diphtheria toxin is the diphthamide residue in translation elongation factor 2 (EF-2), which is generated by a three-step post-translational modification of a specific histidine residue in the EF-2 precursor. In the second modification step, an S-adenosylmethionine-dependent methyltransferase, diphthine synthase (DS), catalyzes the trimethylation of the EF-2 precursor. The homodimeric crystal structures of the archaeal diphthine synthases from Pyrococcus horikoshii OT3 and Aeropyrum pernix K1 have been determined. These structures share essentially the same overall fold as the cobalt-precorrin-4 methyltransferase CbiF, confirming that DS belongs to the dimeric class III family of methyltransferases. In the P. horikoshii DS dimer, only one of the two active sites binds the reaction product S-adenosyl-L-homocysteine (AdoHcy), while the other active site contains no ligand. This asymmetric AdoHcy binding may be a consequence of intra-domain and inter-domain movements upon binding of AdoHcy at one of the two sites. These movements disrupt the twofold dimeric symmetry of the DS dimer and probably cause lower AdoHcy affinity at the other binding site. Structures of two archaeal diphthine synthases: insights into the post-translational modification of elongation factor 2.,Kishishita S, Shimizu K, Murayama K, Terada T, Shirouzu M, Yokoyama S, Kunishima N Acta Crystallogr D Biol Crystallogr. 2008 Apr;64(Pt 4):397-406. Epub 2008, Mar 19. PMID:18391406[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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