Interface pocket

We noted in Section VII-2B that, given the set of surface tension values for various crystal planes, the Wulff theorem allowed the construction of fhe equilibrium or minimum firee energy shape. This concept may be applied in reverse small crystals will gradually take on their equilibrium shape upon annealing near their melting point and likewise, small air pockets in a crystal will form equilibrium-shaped voids. The latter phenomenon offers the possible advantage that adventitious contamination of the solid-air interface is less likely. 

Most medium voltage cables are made with insulation shield layers that are bonded but easily stripped from the insulation in order to avoid pockets of air at the interface and at the same time to allow easy field handling for termination and splicing (during installation). 

The quality of bonding is related direcdy to the size and distribution of solidified melt pockets along the interface, especially for dissimilar metal systems that form intermetaUic compounds. The pockets of solidified melt are brittle and contain localized defects which do not affect the composite properties. Explosion-bonding parameters for dissimilar metal systems normally are chosen to minimize the pockets of melt associated with the interface. 

The proteins thus adapt to mutations of buried residues by changing their overall structure, which in the globins involves movements of entire a helices relative to each other. The structure of loop regions changes so that the movement of one a helix is not transmitted to the rest of the structure. Only movements that preserve the geometry of the heme pocket are accepted. Mutations that cause such structural shifts are tolerated because many different combinations of side chains can produce well-packed helix-helix interfaces of similar but not identical geometry and because the shifts are coupled so that the geometry of the active site is retained. 

HRVs are non-enveloped viruses of icosahedral overall shape [44]. Located on the exterior of the viral capsid are three structural proteins (VPl, VP2 and VP3), each consisting of an eight-stranded antiparallel -barrel. VP4 is found at the interface with the RNA inside the virus. A pocket factor is usually bound to a hydrophobic canyon binding site within the VPl -barrel. This lipid-like molecule is important for the stability of the capsid and has been... 

The class III deacetylases, named sirtuins, are structurally and functionally different from other HDACs. In contrast to the zinc-dependent deacetylation of classic HDACs, sirtuins depend on NAD" to carry out catalytic reactions. A variety of sirtuin crystal structures have been published over the past few years. The structures of human Sirt2 and SirtS as well as several bacterial Sir2 proteins could be derived, whereas no 3D structure is available for Sirtl and the other subtypes [69]. All solved sirtuin structures contain a conserved 270-amino-acid catalytic domain with variable N- and C-termini. The structure of the catalytic domain consists of a large classic Rossmann fold and a small zinc binding domain. The interface between the large and the small subdomain is commonly subdivided into A, B and C pockets. This division is based on the interaction of adenine (A), ribose (B) and nicotinamide (C) which are parts of the NAD" cofactor. (Figure 3.5) Whereas the interaction of adenine and... 

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