title: Enacyloxin IIa pinpoints a binding pocket of elongation factor Tu for development of novel antibiotics.
abstract: Elongation factor (EF-) Tu.GTP is the carrier of aminoacyl-tRNA to the programmed ribosome. Enacyloxin IIa inhibits bacterial protein synthesis by hindering the release of EF-Tu.GDP from the ribosome. The crystal structure of the Escherichia coli EF-Tu.guanylyl iminodiphosphate (GDPNP).enacyloxin IIa complex at 2.3 A resolution presented here reveals the location of the antibiotic at the interface of domains 1 and 3. The binding site overlaps that of kirromycin, an antibiotic with a structure that is unrelated to enacyloxin IIa but that also inhibits EF-Tu.GDP release. As one of the major differences, the enacyloxin IIa tail borders a hydrophobic pocket that is occupied by the longer tail of kirromycin, explaining the higher binding affinity of the latter. EF-Tu.GDPNP.enacyloxin IIa shows a disordered effector region that in the Phe-tRNAPhe.EF-Tu (Thermus aquaticus).GDPNP.enacyloxin IIa complex, solved at 3.1 A resolution, is stabilized by the interaction with tRNA. This work clarifies the structural background of the action of enacyloxin IIa and compares its properties with those of kirromycin, opening new perspectives for structure-guided design of novel antibiotics.
authors.affiliation: Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10 C, DK-8000 Aarhus C, Denmark. andrea@bioxray.dk
authors.forename: Andrea
authors.initials: A
authors.lastname: Parmeggiani
authors.forename: Ivo M
authors.initials: IM
authors.lastname: Krab
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Watanabe
authors.forename: Rikke C
authors.initials: RC
authors.lastname: Nielsen
authors.forename: Caroline
authors.initials: C
authors.lastname: Dahlberg
authors.forename: Jens
authors.initials: J
authors.lastname: Nyborg
authors.forename: Poul
authors.initials: P
authors.lastname: Nissen
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry; D010444:Peptide Elongation Factor Tu / Q000737:chemistry*; D011090:Polyenes / Q000737:chemistry; D011728:Pyridones / Q000737:chemistry; D012343:RNA, Transfer; D013824:Thermus / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C503923:GDPNP compound; D011090:Polyenes; D011728:Pyridones; C072734:enacyloxin IIa; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu; C008536:mocimycin