Folding direct

Stone, M. D., et al. (2007). Stepwise protein-mediated RNA folding directs assembly of telomerase ribonucleoprotein. Nature 446, 458—461. 

Stone, M. D., Mihalusova, M., O Connor, C. M., Prathapam, R., Collins, K., and Zhuang, X. (2007). Stepwise protein-mediated RNA folding directs assembly of telo-merase ribonucleoprotein. Nature 446, 458-461. 

Fig. 3.20 CM-AFM deflection (error signal) image of POM lamella (top), height image of a collapsed PE lamella (bottom left) and friction image of the same PE crystal including schematic drawing of fold direction (bottom right). Reproduced with permission from [46] Copyright 1994. Elsevier and [48]. Copyright 1999. American Chemical Society...

The inner membrane (6-8 nm thick) has many folds directed toward the matrix. These invaginations, known as cristae, increase the surface area of the inner membrane. The lipid component, almost all of which is phospholipid, constitutes 30-35% by weight of the inner membrane. 

Microwave radiation increased the rate 1- to 14-fold and the ee 3- to 9-fold (up to 92% ee for one isomer and 96% ee for the other) in the lipase-catalyzed esterification of an alcohol with vinyl acetate.34 Ultrasound increased the rate 7-to 83-fold. Directed evolution can occasionally be used to improve the enantioselectivity of lipases. A lipase for the hydrolysis of racemic p-nitrophenyl 2-methyldecanoate that gave 2% ee was run through four generations of error-prone polymerase chain reactions to raise the selectivity to 81% ee.35... 

Here G is the n-fold direct sum of an arbitrary, simply connected region g in the ordinary 3-space 1, z> g, the physical region of the system where at this stage there is no boundedness requirement for g. Note, however, that in the strict quantum mechanical sense g should be taken as the entire 3-space R, a fact that will require special attention in the proof of the holographic electron density theorem. 

Furthermore, we recall that pgfrj, f2,. .. r ) is an almost everywhere analytic function of the variables r = ri, F2,. .. r consequently, the density function Pg(r) obtained in Eq. 62 is also almost everywhere analytic over the three-dimensional domain g, since it was obtained by integrating an almost everywhere analytic function according to a subset T2, . r of its variables over a finite, (3n -3)-dimensional domain G ", where G " is the (n - l)-fold direct sum of the finite, 3-dimensional domain g, and where r is the variable not involved in the integration. 

For melt-grown polymers the amorphous density is 10-20% lower that the crystal density. Flory argued that all the chains entering the amorphous phase would take a random walk before re-entering the crystal lamellae. A significant fraction of the chains must, however, be fold directly back into the crystal in order to account for the observed low amorphous density. 

Solution-grown single lamellar crystals of, eg, PEO (147), POM (148), PE (149,150), syndiotactic PP, poly(dimethyl silane) (151), poly(4-methyl-pentene) (152), and poly[(i )-3-hydroxybutyrate] (153) deposited onto solid substrates have been studied by SFM. The habit and thickness of the lamellae in flat-on projection are directly accessible and in addition to these data, which have previously been typically provided by TEM in conjunction with shadow evaporation techniques (4), more subtle details of domain boundaries and fold direction orientation have been revealed. In Figure 14, the habit of a collapsed PE lamellae is depicted, as well as the anisotropic lateral force recorded in the different fold sectors (154). 

Fig. 106. Magnetic phase diagram in DyCu for a four-fold direction in the representation of the structures, the arrows correspond to the magnetic moments, the ellipsoids to the quadrupolar moments (after Morin et al. 1990).

Fig. 109. Magnetic phase diagram of TmGaj for a magnetic field along a three-fold direction (after Morin et al. 1987b).

Figure 4. AFM (a), LFM (b) images and relationship between scanning direction of cantilever and chain folding direction (c) of single crystals of the unfractionated HDPE (Mw=520k) single crystal.

The origin of lateral force has not been completely understood yet because the lateral force reflects many properties of sample surface. The results of LFM measurement do not al vays have intuitive explanation, the counterintuitive results in the asymmetric LFM measurement have been obtained in the system of thiolipid monolayer ( ). In the case of PE single crystal, the molecular tilt direction was equivalent in four sectors of one HDPE lamellar single crystal (4). However, the folding direction of HDPE chain on the surface in adjacent sectors of HDPE single crystal seems to be different. Therefore, it is reasonable to consider that the anisotropy of the lateral force in our experiment was due to the difference in folding direction of HDPE chain. 

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