Right-handed coils

In these p-helix structures the polypeptide chain is coiled into a wide helix, formed by p strands separated by loop regions. In the simplest form, the two-sheet p helix, each turn of the helix comprises two p strands and two loop regions (Figure 5.28). This structural unit is repeated three times in extracellular bacterial proteinases to form a right-handed coiled structure which comprises two adjacent three-stranded parallel p sheets with a hydrophobic core in between. 

The important bacterial storage material poly-hydroxybutyric acid is related metabolically and structurally to the lipids. This highly reduced polymer is made up of D-(3-hydroxybutyric acid units in ester linkage, about 1500 residues being present per chain. The structure is that of a compact right-handed coil with a twofold screw axis and a pitch of 0.60 nm.a Within bacteria it often occurs in thin lamellae 5.0 nm thick. Since a chain of 1500 residues stretches to 440 nm, there must be 88 folds in a single chain. Present in both cytoplasmic granules and in membranes,b polyhydroxybutyrate can account for as much as 50% of the total carbon of some bacterial In E. coli and many other bacteria polyhydroxybutyrate is present in a lower molecular mass form bound to calcium polyphosphates, proteins, or other macromolecules.d e It has also been extracted from bovine serum albumin and may be ubiquitous in both eukaryotes and prokaryotes.d/e The polymer may function in formation of Ca2+ channels in membranes.b/d... 

Fig. 4. The structure of human vasodilator-stimulated phosphoprotein (VASP) is that of a parallel chain, four-stranded coiled-coil (Kuhnel et al., 2004). The sequence contains a pair of 15-residue repeats, resulting in the formation of a right-handed coiled coil with a pitch length of 18.5 nm, a value directly comparable to that seen in left-handed two-stranded coiled coils. Figure courtesy of Sergei Strelkov.

Kiihnel, K., Jarchau, T., Wolf, E., Schlichting, I., Walter, U., Wittinghofer, A., and Strelkov, S. V. (2004). The VASP tetramerization domain is a right-handed coiled coil based on a 15-residue repeat. Proc. Natl. Acad. Sci. USA 101, 17027-17032. 

Stetefeld, J., Jenny, M., Schulthess, T., Landwehr, R., Engel, J., and Kammerer, R. A. (2000). Crystal structure of a naturally occurring parallel right-handed coiled coil tetramer. Nat. Struct. Biol. 7, 772-776. 

Peters, J., Baumeister, W., and Lupas, A. (1996). Hyperthermostable surface layer protein tetrabrachion from the archaebacterium Staphylothermus marinusr. Evidence for the presence of a right-handed coiled coil derived from the primary structure. / Mol. Biol. 257, 1031-1041. 

Harbury et al. (1998) described a series of peptides designed to form dimeric, trimeric, and tetrameric helical bundles with right-handed supercoils. To achieve right-handed coiled coils, rather than canonical left-handed structures, an HP pattern based on an 11-residue abcdefghij repeat was used as a template. Combinations of the hydrophobic residues Ala, lie, Leu, Val, allo-Ile, and nor-Val were considered for the a, d, and h sites. The... 

The important bacterial storage material poly-hydroxybutyric add is related metabolically and structurally to the lipids. This highly reduced polymer is made up of o-P-hydroxybutyric acid units in ester linkage, about 1500 residues being present per chain. The structure is that of a compact right-handed coil with a twofold screw axis and a pitch of... 

THE CHEMISTRY OF... Selective Binding of Drug Enantiomers to Left- and Right-Handed Coiled DNA 217... 

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