Several variations on this basic structure exist, including alternate backbones such as sphingosine in the sphingolipids, and hydrophilic groups such as phosphate as in phospholipids.
The carbohydrate released from potato pulp by enzyme action consists of the pectinaceous domain galacto-rhamnogalacturonan (GRG), which is an alternating backbone of rhamnose and galacturonic acid substituted with galactose, and, to a smaller extent, arabinose chains (Mohnen 2008; Harholt et al. 2010).
The large polymeric mucins are composed of subunits linked by disulphide bonds, and within each subunit stretches of naked protein backbone alternate with highly glycosylated regions containing large numbers of oligosaccharide side chains [ 14].
The analysis of the carboxin-bound structure (2WDQ) suggests an alternate path through backbone covalent bonds of Cys-206 and His-207 of SdhB, then a through-space jump from the CD2 atom of the imidazole ring of His-207, and then on to carboxin (path 3, Figure 2).
However, new discoveries and reexamination of existing Stegosaurus specimens since the 1970s suggest that the plates alternated along the backbone, as no two plates from the same animal have exactly the same shape or size.
The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone.
Two new soluble block copolymers are reported in which chromophores and hexa ethylene oxide) units alternate along the polymer backbone.
> -wrap-foot> In the deposited model, the alternate side-chain and backbone conformations for Val168 have a relatively large Cβ displacement (0.66 Å).
Polymeric electron donor materials are typically designed using a push pull strategy where electron-rich and electron-deficient π-conjugated motifs alternate along the polymer backbone, whereupon molecular orbital hybridization results in a narrow band gap material with good spectral overlap with the solar spectrum.
