Bundle formations

Wang, E. (1985). Are cross-bridging strucmres involved in the bundle formation of intermediate filaments and the decrease in locomotion that accompany cell aging J. Cell Biol. 100,1466-1473. 

Turning to polymers giving thermodynamically stable mesophases we must assume that, since we have described bundles as an inherent structural feature of undercooled polymer melts, such structures should occur, at least in principle, also in such systems, to the extent that attractive interchain interactions which account for bundle formation play a significant role. On the other hand, rigorously speaking Class II mesophases are entropy-stabilized and inter-chain... 

In the perspective discussed in the present contribution, bundle formation occurs within the amorphous phase and in undercooled polymer solutions. It does not imply necessarily a phase separation process, which, however, may occur by bundle aggregation, typically at large undercoolings [mode (ii)]. In this case kinetic parameters relating to chain entanglements and to the viscous drag assume a paramount importance. Here again, molecular dynamics simulations can be expected to provide important parameters for theoretical developments in turn these could orient new simulations in a fruitful mutual interaction. 

Lacerda L, Pastorin G, Wu W, Prato M, Bianco A, Kostarelos K (2006b) Luminescence of functionalized carbon nanotubes as a tool to monitor bundle formation and dissociation in water The effect of plasmid-DNA complexation. Adv. Funct. Mater. 16 1839-1846. 

Jiang S, Lu H, Liu S et al (2004) N-substituted pyrrole derivatives as novel human immunodeficiency virus type 1 entry inhibitors that interfere with the gp41 six-helix bundle formation and block virus fusion. Antimicrob Agents Chemother 48 4349-4359... 

Liu B, Joseph RW, Dorsey BD et al (2009) Structure-based design of substituted biphenyl ethylene ethers as ligands binding in the hydro-phobic pocket of gp41 and blocking the helical bundle formation. Bioorg Med Chem Lett 19 5693-5697... 

Fig. 35 SEM images of the perovskite nanotubes (a) side-view showing the bundle formation after removal of the template (b) top-view of PbTiOj bundles showing the open ends. (Reproduced with permission from ref. 102).

Brandt R, Lee G (1993) Functional organization of microtubule-associated protein tau. Identification of regions which affect microtubule growth, nucleation, and bundle formation... 

Tang JX, janmey PA. The polyelcctrolyte nature of F-actin and the mechanism of actin bundle formation. J Biol Chem 1996 271 8556-8563. 

We envisioned a two-step process [114,115] for the insertion and association of fluorinated transmembrane (TM) helices. First, the hydrophobic TM peptides would partition into micelles or vesicles and form a-helices by main-chain hydrogen bonding. Upon secondary structure formation, one face of the helices would present a highly fluorinated surface. Second, phase separation of fluorinated surfaces within hydrophobic environments would mediate helix-helix interactions, driving bundle formation. 

Connectin also causes aggregation of actin filaments in a manner similar to myosin at low ionic strengths (Kimura and Maruyama, 1983a Kimura et ai, 1984b). Bundles of actin filaments wee formed in the presence of connectin. The bundles appeared to resemble those formed by a-actinin. However, unlike the case with a-actinin, bundle formation by connectin was not affected by tropomyosin bound to actin filaments (H. Yoshidomi, unpublished results). Furthermore, the 400-kDa fragment of connectin did not act on actin filaments at all. It is likely that connectin filaments enhance bundle formation of actin filaments by topological restrictions. 

Shklovskii BI. Wigner crystal model of counterion induced bundle formation of rodlike polyelectrolytes. Phys. Rev. Lett. 1999 82 3268-3271. 

The analysis above appears to contradict the experimental finding of a well-defined finite bundle size. We argue that the experimental observation is not an equilibrium effect, and that the kinetics of bundle formation lead to a well-defined size. In fact, we believe that the competition of the short-range attraction and longer range repulsion leads to unique kinetics of bundle growth [47]. 

J. X. Tang, S. E. Wong, P. T. Tran, and P. A. Janmey. Counterion induced bundle formation of rodlike poly electrolytes. Berichte der Bunsen-Gesellschaft —Physical Chemistry, Chemical Physics 100 796-806 (1996). 

Debnath AK (2006) Prospects and strategies for the discovery and development of small-molecule inhibitors of six-helix bundle formation in class 1 viral fusion proteins. Curr Opin Investig Drugs 7 118-127... 

Roymans D, De Bondt FLL, Amoult E et al (2010) Binding of a potent small-molecule inhibitor of six-helix bundle formation requires interactions with both heptad-repeats of the RSV fusion protein. Proc Natl Acad Sci USA 107 308-313... 

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