What is the purpose of having a coiled coil?
Because of their specific interaction coiled coils can be used as a “tags” to stabilize or enforce a specific oligomerization state. A coiled coil interaction has been observed to drive the oligomerization of the BBS2 and BBS7 subunits of the BBSome.
Does keratin have coiled-coils?
The secondary structure of α-keratin is very similar to that of a traditional protein α-helix and forms a coiled coil. Due to its tightly wound structure, it can function as one of the strongest biological materials and has various functions in mammals, from predatory claws to hair for warmth.
Why are coiled-coils left-handed?
The slight discrepancy between the 3.6 residues per turn of a normal alpha helix and the 3.5-residue repeat of the a- and d-residues causes this hydrophobic strip to wrap about its alpha helix in a gentle left-handed helix, thereby accounting for the formation of the left-handed coiled coil.
Does collagen have coiled-coils?
The collagen triple-helix and the alpha-helical coiled coil represent the two basic supercoiled multistranded protein motifs. Originally they were characterized in fibrous proteins, but have been found more recently in a number of other proteins containing rod-shaped domains.
Are coiled coils quaternary?
The coiled-coil is a ubiquitous protein folding and assembly motif made of alpha-helices wrapping around each other forming a supercoil. It is pointed out that the primary sequences of coiled-coils over specify the secondary structure but under specify the tertiary/quaternary structure.
Are coiled coils hydrophobic?
Most core residues of coiled coils are hydrophobic. Occasional polar residues are thought to lower stability, but impart structural specificity.
Is coiled coil secondary structure?
Keyword – Coiled coil (KW-0175) Protein which contains at least one coiled coil domain, a type of secondary structure composed of two or more alpha helices which entwine to form a cable structure. In proteins, the helical cables serve a mechanical role in forming stiff bundles of fibres.
How is coiled coil formed?
Coiled coils are formed when two or more α-helices self-assemble by winding around each other to form a left-handed supercoil (Fig. 3.1C). Although dimers, trimers, and tetramers are the most common structures, larger coiled-coils of up to seven helices can now be prescriptively designed [8].
Is collagen alpha helical?
Due to the high abundance of glycine and proline contents, collagen fails to form a regular α-helix and β-sheet structure. Three left-handed helical strands twist to form a right-handed triple helix. The hydrogen bond donors are the peptide NH groups of glycine residues.
What happens when the glycine residues of collagen are mutated?
Glycine is required as every third residue in the collagen triple-helix, and a missense mutation leading to the replacement of even one Gly in the repeating (Gly-Xaa-Yaa)n sequence by a larger residue leads to a pathological condition.
Is DNA a coiled-coil?
We report the coiled-coil structure of DNA, which is generated by the dodecanucleotide d(ATATATATATAT). The structure has been determined by single-crystal x-ray crystallography. The coiled coils have six dodecamer duplexes per turn. Despite the presence of nicks, the structure is very rigid.