Coiled-coil motifs

Sorger, P.K. Nelson, H.C.M. (1989). Trimerization of a yeast transcriptional activator via a coiled-coil motif. Cell 59, 807-813. 

The characteristic coiled-coil motifs found in proteins share an (abcdefg) heptad repeat of polar and nonpolar amino acid residues (Fig. 1). In this motif, positions a, d, e, and g are responsible for directing the dimer interface, whereas positions b, c, and f are exposed on the surfaces of coiled-coil assemblies. Positions a and d are usually occupied by hydrophobic residues responsible for interhelical hydrophobic interactions. Tailoring positions a, d, e, and g facilitates responsiveness to environmental conditions. Two or more a-helix peptides can self-assemble with one another and exclude hydrophobic regions from the aqueous environment [74]. Seven-helix coiled-coil geometries have also been demonstrated [75]. 

Vandermeulen GWM, Tziatzios C, Klok HA (2003) Reversible self-organization of poly (ethylene glycol)-based hybrid block copolymers mediated by a de novo four- stranded alpha-helical coiled coil motif Macromolecules 36 4107 114... 

The GPCR C-terminal region, with or without a coiled-coil motif, has been implicated in the heterodimerization process of GABAb(1)-GABAb(2) (78,80), as well as in the homodimerization of 5-opioid receptor (120). However, the possibility cannot be ruled out that the indirect evidence for the involvement of the C-terminal domain results from changes produced by the deletion of the C-terminal tail, that alters the conformation of the receptors and causes decreased interactions between transmembrane helices and oligomer disruption. 

Qu, Y., Hyman, P., Harrah, T., and Goldberg, E. (2004). In vivo bypass of chaperone by extended coiled-coil motif in T4 tail fiber./. Bacteriol. 186, 8363-8369. 

The coiled-coil motif is not strictly a specific fold but the description is appHed to structures where helical segments are based on the heptad repeat abcdefg) . 

Zimenkov Y, Conticello VP, Guo L, Thiyagarajan P. Rational design of a nanoscale helical scaffold derived fi om self-assembly of a dimeric coiled coil motif. Tetrahedron 2004 60 ... 

By examining the amino add sequence of tropomyosin, the smallest and simplest proteins postulated at the time 1819 to contain the coiled-coil motif, we identified the hydrophobic repeat responsible for the formation and stabilization of the coiled-coil structure. 18 A coiled coil can be considered as a repeating heptad of seven amino acid residues a-b-c-d-e-f-g, where positions a and d are occupied by hydrophobic residues. This 3-4 (or 4-3) hydro-... 

The coiled-coil motif is an ideal model system for the following reasons there is only one type of secondary structure present (the a-helix) the a-helical structure can be easily monitored by circular dichroism spectroscopy the two-stranded coiled coil contains two subunits stabilized by both intrachain and interchain interactions and, lastly, its small size reduces the potential complexity in the analysis and interpretation of results encountered in the analysis of globular proteins, which have multiple elements of secondary structure (a-helix, (3-sheet, (3-turns, loops, and regions of undefined structure). 

Walshaw, J., and Woolfson, D. N. (2001). SOCKET A program for identifying and analyzing coiled-coil motifs within protein structures. J. Mol. Biol. 307, 1427-1450. 

Coiled-coil motifs have been known to play roles in conformational switching in natural proteins for some time (Oas and Endow, 1994). The key examples are influenza hemagglutinin (Bullough et al., 1994 Carr and Kim, 1993 Carr et al., 1997), and the heat shock transcription factor (Rabindran et al., 1993). Furthermore, an engineered form of GCN4-pl, with Asn-16 replaced by Ala, switches from dimer to trimer upon addition of... 

Sadoulet-Puccio, H.M., Rajala, M., and Kunkel, L.M., 1997, Dystrobrevin and dystrophin an interaction through coiled-coil motifs, Proc Natl Acad Sci USA, 94, pp 12413-12418. 

A protein that would be a logical interaction partner for SPT is 3-ketosphinganine reductase, which catalyzes the next step of the sphingolipid biosynthetic pathway. The gene for this reductase has been identified in yeast (T. Beeler, 1998) and in mammals (FVTl) (A. Kihara, 2004), and the sequence has coil-coil motifs that might interact with a similar motifs on SPT. 

Coiled coil, motifs of super-secondary structure found in proteins. Approximately 2-3% of aU proteins form coiled coils, where two to seven amphipathic a-helices are wrapped around each other, like the strands of a rope. The interaction surface of these amphipathic helices is of hydrophobic nature, and leucine is often found in the position of the hydrophobic amino acids (leucine zipper). This hydrophobic interaction provides, in an aqueous environment, the driving force for the di- or oligomerization. Coiled coils of two or three helical domains are the most commonly found types. In the former case, the two helices are wound up against each other in a left-handed twist with a seven-residue periodicity. Packing of unpolar side chains (u) into a hydrophobic core mainly contributes to the stability of this super-secondary fold. The dimeric coiled coU is, for example, responsible for DNA recognition by some transcription factors. 

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