Superimposed oxygen atoms

In some of the diagrams superimposed oxygen atoms have been displaced slightly for clarity. 

The carbonyl motions of the carbonate group can be accounted for by considering jumps between two sites, corresponding to a rotation around an axis perpendicular to the C = O bond in the plane formed by the three oxygen atoms, with an angle of 40° between the two sites, over which is superimposed a rotation of 15° about the C = O bond. This latter motion requires a main-chain reorientation motion. 

R-band are mostly connected with motions of oxygen atoms, which actually determine the harmonic-oscillator response. Hence, these facts would be difficult to interpret if we didn t accept the viewpoint that cooperative effects should be superimposed on the motions of a water molecule as a whole. 

Carbinoxamine is a potent antihistaminic and is available as the racemic mixture. Carbinoxamine differs structurally from chlorpheniramine only in having an oxygen atom separate the asymmetric carbon atom from the aminoethyl side chain. The more active leva isomer of carbinoxamine has the (5) absolute configuration and can be superimposed on the more active dextro isomer (S configuration ) of chlorpheniramine. 

The drawing shows a small portion of a single layer of protein molecules (polypeptide chains) in a silk fiber. These molecules are attached to adjacent molecules in the layer by the formation of hydrogen bonds, which extend laterally from the NH group of one chain to the oxygen atom of an adjacent chain. The fiber consists of many of these hydrogen-bonded layers superimposed upon one another. 

Fig. 6. The water structure in the active site of bovine SOD as obtained from the crystal structure of the reduced enzyme at pH 7.5 (ISXA). The water molecules are represented as spheres of radius corresponding to the van der Waals radius of the oxygen atom, superimposed on the ribbon diagram of the enzyme.

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