helix (redirected from helices)

helix /he·lix/ (he´liks) pl. he´lices, helixes   [Gr.]

1. spiral (2).

2. the superior and posterior free margin of the pinna of the ear.

---

α-helix , alpha helix the structural arrangement of parts of protein molecules in which a single polypeptide chain forms a right-handed helix stabilized by intrachain hydrogen bonds.

double helix , Watson-Crick helix a representation of the structure of DNA, consisting of two coiled chains arranged antiparallel to each other, each containing information completely specifying the other chain.

---

he·lix (hlks)

n. pl. he·lix·es or hel·i·ces (hl-sz, hl-)

1. A spiral form or structure.

2. The folded rim of skin and cartilage around most of the outer ear.

3. A three-dimensional curve that lies on a cylinder or cone, so that its angle to a plane perpendicular to the axis is constant.

---

helix

[hē′liks]

Etymology: Gk, coil

1 a coiled, spiral-like formation characteristic of many organic molecules, such as DNA.

2 the large outside rim of the auricle.

---

helix

1. a coiled structure.

2. the free margin of the pinna of the ear.

---

α-helix, alpha-helix

the folding arrangement of parts of protein molecules in which a single polypeptide chain forms a right-handed helix.

helix destabilizing proteins

proteins that bind in a cooperative manner to DNA single-strands during DNA replication and help open up the replication fork. Called also single-strand DNA binding proteins.

double helix

the native state of deoxyribonucleic acid (DNA), in which two antiparallel chains with complementary nucleotide sequences are wound around each other. The DNA molecule consists of two sugar-phosphate strands with the nucleotide base pairs stacked between them. The orientation of the two strands is antiparallel, i.e. 5′→3′ directions are opposite. Called also Watson-Crick helix.