Conformation bending

Chuman, H., F. A. Momany, and L. Schafer. 1984. Backbone Conformations, Bend Structures, Helix Structures, and Other Tests of an Improved Conformational Energy Program for Peptides ECEPP83. Int. J. Pept. Prot. Res. 24, 233-248. 

OLED on an Al-PET substrate. The device performance does not deteriorate after repeated bending, suggesting that there is no significant stress-induced change in the characteristics of the OLEDs fabricated on PET foil [71,82]. The results demonstrate the feasibility of fabricating flexible displays using a variety of plastic substrates including metal-laminated plastic foils, or a metal film sandwiched between two plastic foils. The flexible device structures enable a display to conform, bend, or roll into any shape and thus make possible other product concepts. 

Conformable Bend once Can be fit to an uneven or curved surface... 

The first technique is very intuitive. Out of the few proteins that could be crystallized in a number of different conformations, adenylate kinase is probably the best-studied example. By combining nine observed crystal structures and interpolating between them, a movie was constructed that visualized a hypothetical path of its hinge-bending transition (jVonrhein et al. 1995]). 

A4) Bond angle bending makes a nonnegligible contribution to conformational entropy and can affect computed equilibrium populations [11]. 

In complexes with Cro, the overall bend and twist of the DNA are similar to those in the repressor complexes, but there is a significant difference in the local structure of two of the nucleotides in each half-site. Binding of 434 Cro or repressor fragment thus imposes a distinct local structure (Figure 8.13), as a result of differences in both the identity and conformations of various amino acid residues that interact with the DNA. The DNA conformational details are significant for the relative affinities of Cro and repressor for various sites, as we describe in a later section. 

Some of the procaryotic DNA-binding proteins are activated by the binding of an allosteric effector molecule. This event changes the conformation of the dimeric protein, causing the helix-tum-helix motifs to move so that they are 34 A apart and able to bind to the major groove. The dimeric repressor for purine biosynthesis, PurR, induces a sharp bend in DNA upon binding caused by insertion of a helices in the minor groove between the two... 

The picture presented so far of the polyethylene chain being of a linear zig-zag geometry is an idealised one. The conformation of a molecular chain is in fact random provided that the bond tetrahedral angle remains fixed. This is best illustrated by considering a piece of wire with one bend at an angle of 109° 28 as shown in Fig. A.5a. 

FIG. 15 Conformations of fluid vesicles for different values of the bending rigidity and pressure increment (a) branched polymer (b) inflated vesicle (c) prolate vesicle (d) stomatocyte. (From Gompper and Kroll [243]. Copyright 1995 APS.)... 

When the polypeptide chains of protein molecules bend and fold in order to assume a more compact three-dimensional shape, a tertiary (3°) level of structure is generated (Figure 5.9). It is by virtue of their tertiary structure that proteins adopt a globular shape. A globular conformation gives the lowest surface-to-volume ratio, minimizing interaction of the protein with the surrounding environment. 

The parameter redundancy is also the reason that care should be exercised when trying to decompose energy differences into individual terms. Although it may be possible to rationalize the preference of one conformation over another by for example increased steric repulsion between certain atom pairs, this is intimately related to the chosen functional form for the non-bonded energy, and the balance between this and the angle bend/torsional terms. The rotational banier in ethane, for example, may be reproduced solely by an HCCH torsional energy term, solely by an H-H van der Waals repulsion or solely by H-H electrostatic repulsion. Different force fields will have (slightly) different balances of these terms, and while one force field may contribute a conformational difference primarily to steric interactions, another may have the... 

The design of pipework has to be such as to allow access to welds and bends for weld and surface preparation. It is preferable to use seamless tubing conforming to BS 806 1986. Where this is impractical, tubing in accordance with BS 1387 1985 is acceptable provided that the butt-welded joint seam does not restrict the bore by more than 0-25 mm. 

Hydrophobicity plots of AQPs indicated that these proteins consist of six transmembrane a-helices (Hl-H6 in Fig. la) connected by five connecting loops (A-E), and flanked by cytosolic N- and C-termini. The second half of the molecule is an evolutionary duplicate and inverse orientation of the first half of the molecule. Loops B and E of the channel bend into the membrane with an a-helical conformation (HB, HE in Fig. lb) and meet and each other at their so-called Asn-Pro-Ala (NPA) boxes. These NPA motifs are the hallmark of AQPs and form the actual selective pore of the channel, as at this location, the diameter is of that of a water molecule (3 A Fig. la and b). Based on the narrowing of the channel from both membrane sides to this small... 

The HMG (high mobility group) box is a DNA-binding domain found in several transcription factors, that can in some cases bend DNA. Some members of this protein family recognize a unique DNA sequence, whereas others bind to a common DNA conformation. 

The reader is asked (see Problem 6.17) to devise two schemes that conform to Fig. 6-1 b. Again this is a downward bend (i.e., the order with respect to [H+] decreases with increasing [H+]), which signals that the pH effect arises from a substrate titration. 

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