3ZZ0

Crystal structure of ribosomal elongation factor (EF)-G from Staphylococcus aureus with a fusidic acid hyper-sensitivity mutation M16I

Summary for 3ZZ0

• Entry DOI: 10.2210/pdb3zz0/pdb
• Related: 2XEX 3ZZT 3ZZU
• Descriptor: Elongation factor G (2 entities in total)
• Functional Keywords: translation, gtpase, five-domain structure
• Biological source: Staphylococcus aureus
• Total number of polymer chains: 2
• Total formula weight: 153362.50

Authors

Koripella, R.K.,Chen, Y.,Selmer, M.,Sanyal, S. (deposition date: 2011-08-30, release date: 2012-07-18, Last modification date: 2023-12-20)

Primary citation

Koripella, R.K.,Chen, Y.,Peisker, K.,Koh, C.S.,Selmer, M.,Sanyal, S.
Mechanism of elongation factor-G-mediated fusidic acid resistance and fitness compensation in Staphylococcus aureus.
J. Biol. Chem., 287:30257-30267, 2012

PubMed Abstract: Antibiotic resistance in bacteria is often associated with fitness loss, which is compensated by secondary mutations. Fusidic acid (FA), an antibiotic used against pathogenic bacteria Staphylococcus aureus, locks elongation factor-G (EF-G) to the ribosome after GTP hydrolysis. To clarify the mechanism of fitness loss and compensation in relation to FA resistance, we have characterized three S. aureus EF-G mutants with fast kinetics and crystal structures. Our results show that a significantly slower tRNA translocation and ribosome recycling, plus increased peptidyl-tRNA drop-off, are the causes for fitness defects of the primary FA-resistant mutant F88L. The double mutant F88L/M16I is three to four times faster than F88L in both reactions and showed no tRNA drop-off, explaining its fitness compensatory phenotype. The M16I mutation alone showed hypersensitivity to FA, higher activity, and somewhat increased affinity to GTP. The crystal structures demonstrate that Phe-88 in switch II is a key residue for FA locking and also for triggering interdomain movements in EF-G essential for its function, explaining functional deficiencies in F88L. The mutation M16I loosens the hydrophobic core in the G domain and affects domain I to domain II contact, resulting in improved activity both in the wild-type and F88L background. Thus, FA-resistant EF-G mutations causing fitness loss and compensation operate by affecting the conformational dynamics of EF-G on the ribosome.

PubMed: 22767604
DOI: 10.1074/jbc.M112.378521

Experimental method

X-RAY DIFFRACTION (2.8 Å)