Didemnin B (Synonyms: NSC 325319, NSC 333841)

Preparation Method

The eEF1A·GTP·Mg2+ and Didemnin B·eEF1A·GTP·Mg2+ complexes were solvated by adding a spherical shell of ∼3000 TIP3P water molecules centered at CG1 of Leu77. The radius of this water shell was 35 Å to ensure the solvation of the interdomain cleft in both complexes. These water molecules were first energy-minimized, and then both waters and all protein residues were allowed to relax. In each case, 1000 steps of steepest descent were followed by 2000 steps of conjugate gradient energy minimization. The final coordinate sets were used as input for the subsequent MD simulations. SHAKE was used for all bonds, and the integration time step was 2 fs. Only the water molecules were free to move for the first 100 ps. For the remaining 2000 ps the whole system was allowed to relax.

Applications

Didemnin B specifically binds GTP-bound eEF1A-1, in a location between the aa-tRNA-binding and GTP-binding domains, but distinct from the actin-binding domain. Didemnin B thereby specifically inhibits eEF1A-1 release from the ribosomal A-site, preventing peptidyl-tRNA translocation and subsequent peptide elongation.

Cell lines

HepG2 cells

Preparation Method

Cells were treated with palmitate, with or without 80 nM didemnin B, followed by assessment of ER stress (6 h), protein synthesis (6-24 h), and cell death (48 h).

Reaction Conditions

80 nM didemnin B for 6-48 h

Applications

Didemnin B prevent upregulation of GRP78 protein in HepG2 cells，in association with sustained inhibition of protein synthesis.

Animal models

Five-week-old male C57BL/6J and leptin-deficient (ob/ob) mice on a C57BL/6J background

Preparation Method

Used 5-week-old male C57BL/6J (lean control) and leptin-deficient ob/ob mice. All mice were fed AIN-76A diet for 4 weeks. During week 5, mice were given i.p. injections of didemnin B (50 μg/kg) or vehicle control on days 1, 4, and 7.

Dosage form

didemnin B (50 μg/kg) on days 1, 4, and 7( i.p. injections)

Applications

Didemnin B treatment modestly reduces food consumption in obese mice.

References:

[1]. Marco E, Martín-Santamaría S, et,al. Structural basis for the binding of didemnins to human elongation factor eEF1A and rationale for the potent antitumor activity of these marine natural products. J Med Chem. 2004 Aug 26;47(18):4439-52. doi: 10.1021/jm0306428. PMID: 15317456.

[2]. Stoianov AM, Robson DL, et,al. Elongation Factor 1A-1 Is a Mediator of Hepatocyte Lipotoxicity Partly through Its Canonical Function in Protein Synthesis. PLoS One. 2015 Jun 23;10(6):e0131269. doi: 10.1371/journal.pone.0131269. PMID: 26102086; PMCID: PMC4478042.

[3]. Hetherington AM, Sawyez CG, et,al.Treatment with didemnin B, an elongation factor 1A inhibitor, improves hepatic lipotoxicity in obese mice. Physiol Rep. 2016 Sep;4(17):e12963. doi: 10.14814/phy2.12963. PMID: 27613825; PMCID: PMC5027364.