title: Structures, Properties, and Dynamics of Intermediates in eEF2-Diphthamide Biosynthesis.
abstract: The eukaryotic translation Elongation Factor 2 (eEF2) is an essential enzyme in protein synthesis. eEF2 contains a unique modification of a histidine (His699 in yeast; HIS) into diphthamide (DTA), obtained via 3-amino-3-carboxypropyl (ACP) and diphthine (DTI) intermediates in the biosynthetic pathway. This essential and unique modification is also vulnerable, in that it can be efficiently targeted by NAD(+)-dependent ADP-ribosylase toxins, such as diphtheria toxin (DT). However, none of the intermediates in the biosynthesis path is equally vulnerable against the toxins. This study aims to address the different susceptibility of DTA and its precursors against bacterial toxins. We have herein undertaken a detailed in silico study of the structural features and dynamic motion of different His699 intermediates along the diphthamide synthesis pathway (HIS, ACP, DTI, DTA). The study points out that DTA forms a strong hydrogen bond with an asparagine which might explain the ADP-ribosylation mechanism caused by the diphtheria toxin (DT). Finally, in silico mutagenesis studies were performed on the DTA modified protein, in order to hamper the formation of such a hydrogen bond. The results indicate that the mutant structure might in fact be less susceptible to attack by DT and thereby behave similarly to DTI in this respect.
authors.affiliation: Department of Chemical and Physical Biology, Center for Biological Research, CIB-CSIC , 28040 Madrid, Spain.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Billod
authors.affiliation: Computational Chemistry and Biology Group, Facultad de Química, Universidad de la República , 11800 Montevideo, Uruguay.
authors.forename: Patricia
authors.initials: P
authors.lastname: Saenz-Mendez
authors.forename: Anders
authors.initials: A
authors.lastname: Blomberg
authors.forename: Leif A
authors.initials: LA
authors.lastname: Eriksson
mesh_terms: D003198:Computer Simulation; D006639:Histidine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D056004:Molecular Dynamics Simulation; D016296:Mutagenesis; D020652:Peptide Elongation Factor 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism
chemical_list: D020652:Peptide Elongation Factor 2; D006639:Histidine; C027527:diphthamide