More Like this

1. Membrane-mediated dimerization of spherocylindrical nanoparticles

   https://doi.org/10.1039/d2sm01574a  

   Sharma, Abash; Zhu, Yu; Spangler, Eric J.; Carrillo, Jan-Michael Y.; Laradji, Mohamed (February 2023, Soft Matter)

   We present a numerical investigation of the modes of adhesion and endocytosis of two spherocylindrical nanoparticles (SCNPs) on planar and tensionless lipid membranes, using systematic molecular dynamics simulations of an implicit-solvent model, with varying values of the SCNPs' adhesion strength and dimensions. We found that at weak values of the adhesion energy per unit of area, ξ , the SCNPs are monomeric and adhere to the membrane in the parallel mode. As ξ is slightly increased, the SCNPs dimerize into wedged dimers, with an obtuse angle between their major axes that decreases with increasing ξ . However, as ξ is further increased, we found that the final adhesion state of the two SCNPs is strongly affected by the initial distance, d 0 , between their centers of mass, upon their adhesion. Namely, the SCNPs dimerize into wedged dimers, with an acute angle between their major axes, if d 0 is relatively small. However, for relatively high d 0 , they adhere individually to the membrane in the monomeric normal mode. For even higher values of ξ and small values of d 0 , the SCNPs cluster into tubular dimers. However, they remain monomeric if d 0 is high. Finally, the SCNPs endocytose either as a tubular dimer, if d 0 is low or as monomers for large d 0 , with the onset value of ξ of dimeric endocytosis being lower than that of monomeric endocytosis. Dimeric endocytosis requires that the SCNPs adhere simultaneously at nearby locations. 

   more » « less
2. Folding-Assisted Peptide Disulfide Formation and Dimerization

   https://doi.org/10.1021/acschembio.3c00268  

   Victorio, Clara G; Sawyer, Nicholas (June 2023, ACS Chemical Biology)
3. Iron‐Catalyzed Gamma‐Gamma Dimerization of Siloxydienes

   https://doi.org/10.1002/chem.202302901  

   Galaktionova, Daria; Liu, Xiaoguang; Chen, Xiaohong; Mohr, Justin_T (December 2023, Chemistry – A European Journal)

   Abstract We report the oxidative dimerization reaction of siloxydienes derived from simple enones that creates a new gamma‐gamma (γ‐γ) C−C bond using catalytic iron and benzoyl peroxide as the terminal oxidant in acetonitrile solvent at ambient temperature. The reaction shows a broad substrate scope including cyclic and acyclic siloxydienes derived from ketones, aldehydes, and esters, which are converted to 1,8‐dicarbonyl compounds under mild catalytic reaction conditions in 19–89 % yield across 30 examples. The method is suitable for the coupling of sterically demanding carbon centers, including the formation of vicinal quaternary centers. Conceptually, the dienol ether serves as a precursor to a conjugated radical cation, which undergoes highly site selective γ‐dimerization reactions. The γ‐γ dimerization strategy is applied to the synthesis of a bioactive analogue of honokiol. 

   more » « less
4. Membrane-mediated dimerization potentiates PIP5K lipid kinase activity

   https://doi.org/10.7554/elife.73747  

   Hansen, Scott D; Lee, Albert A; Duewell, Benjamin R; Groves, Jay T (August 2022, eLife)

   The phosphatidylinositol 4-phosphate 5-kinase (PIP5K) family of lipid-modifying enzymes generate the majority of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P 2 ] lipids found at the plasma membrane in eukaryotic cells. PI(4,5)P 2 lipids serve a critical role in regulating receptor activation, ion channel gating, endocytosis, and actin nucleation. Here, we describe how PIP5K activity is regulated by cooperative binding to PI(4,5)P 2 lipids and membrane-mediated dimerization of the kinase domain. In contrast to constitutively dimeric phosphatidylinositol 5-phosphate 4-kinase (PIP4K, type II PIPK), solution PIP5K exists in a weak monomer–dimer equilibrium. PIP5K monomers can associate with PI(4,5)P 2 -containing membranes and dimerize in a protein density-dependent manner. Although dispensable for cooperative PI(4,5)P 2 binding, dimerization enhances the catalytic efficiency of PIP5K through a mechanism consistent with allosteric regulation. Additionally, dimerization amplifies stochastic variation in the kinase reaction velocity and strengthens effects such as the recently described stochastic geometry sensing. Overall, the mechanism of PIP5K membrane binding creates a broad dynamic range of lipid kinase activities that are coupled to the density of PI(4,5)P 2 and membrane-bound kinase. 

   more » « less
5. Divergence in Dimerization and Activity of Primate APOBEC3C

   https://doi.org/10.1016/j.jmb.2021.167306  

   Gaba, Amit; Hix, Mark A.; Suhail, Sana; Flath, Ben; Boysan, Brock; Williams, Danielle R.; Pelletier, Tomas; Emerman, Michael; Morcos, Faruck; Cisneros, G. Andrés; et al (December 2021, Journal of Molecular Biology)

   null (Ed.)