Helices in a sentence

A comparison of the two principal nucleic acids: RNA (left) and DNA (right), showing the helices and nucleobases each employs.

Alpha helices are shown as thick blue bands, and random coil as thinner blue lines.

An example of both aspects is the transcription factor Max (see image at left), which uses a helical coiled-coil to dimerize, positioning another pair of helices for interaction in two successive turns of the DNA major groove.

Birefringence of this sort is possible even in a fluid because the handedness of the helices is not dependent on their orientation: even when the direction of one helix is reversed, it still appears right handed.

Chemistry 12. Toronto: Nelson, p. 122. Most of the amino acids in hemoglobin form alpha helices, connected by short non-helical segments.

Chromosomal crossover is when two DNA helices break, swap a section and then rejoin.

Finally, cryo electron microscopy is now capable of discerning individual α-helices within a protein, although their assignment to residues is still an active area of research.

Flagella are left-handed helices, and bundle and rotate together only when rotating counterclockwise.

Histones dimerise about their long α2 helices in an anti-parallel orientation, and, in the case of H3 and H4, two such dimers form a 4-helix bundle stabilised by extensive H3-H3’ interaction.

In lefthanded β-helices, the strands themselves are quite straight and untwisted; the resulting helical surfaces are nearly flat, forming a regular triangular prism shape, as shown for the 1QRE archaeal carbonic anhydrase at right.

In proteins, structures such as alpha helices and beta sheets are chiral, and thus absorb such light.

It also contains two domains comprising six alpha helices apiece, which allow the protein to cross the cell membrane.

Larger-scale assemblies The Hemoglobin molecule has four heme-binding subunits, each made largely of α-helices.

Long homopolymers of amino acids often form helices if soluble.

Note that it is the nature of all screws and helices that it does not matter in which direction you point your thumb when determining its handedness.

On activation, these helices move about and open the pore.

Protein interactions within the nucleosome The core histone proteins contains a characteristic structural motif termed the "histone fold," which consists of three alpha-helices (α1-3) separated by two loops (L1-2).

Protein structures from NMR spectroscopy also show helices well, with characteristic observations of nuclear Overhauser effect (NOE) couplings between atoms on adjacent helical turns.

Secondary structure can be formally defined by the pattern of hydrogen bonds of the protein (such as alpha helices and beta sheets ) that are observed in an atomic-resolution structure.

Some of these cells have walls which contain thickenings in the form of rings or helices.