helix


helix
1. [NA] The margin of the auricle; a folded rim of cartilage forming the upper part of the anterior, the superior, and the greater part of the posterior edges of the auricle. 2. A line in the shape of a coil (or a spring, or the threads on a bolt), each point being equidistant from a straight line that is the axis of the cylinder in which each point of the h. lies; often, mistakenly, applied to a spiral. [L. fr. G. h., a coil]
- 310 h. a type of right-handed h. found in small pieces in a number of proteins; has three amino acid residues per turn.
- 3.613 h. SYN: α h..
- α h. the helical (commonly right-handed) form present in many proteins, deduced by Pauling and Corey from x-ray diffraction studies of proteins such as α-keratin; the h. is stabilized by hydrogen bonds between, e.g., R2C=O and HNR2′ groups (symbolized by the center dot in R2CO HNR2′) of different eupeptide bonds. In a true α h., there are 3.6 amino acid residues per turn of the h. and a rise of 1.5 Å per residue. SYN: 3.613 h., Pauling-Corey h..
- collagen h. an extended left-handed h. resulting from the high levels of glycine, l-proline, and l-hydroxyproline present in the collagens. There are 3.3 amino acid s per turn of the h.. Three of those left-handed helices form a triple superhelix that is right-handed.
- DNA h. SYN: Watson-Crick h..
- double h. SYN: Watson-Crick h..
- π h. a rare right-handed h. found only in small portions of certain proteins. Stabilized by similar hydrogen bonds as in an α h.; there are 4.3 amino acid residues per turn of this h..
- Pauling-Corey h. SYN: α h..
- triple h. the superhelix formed (right-handed) from three individual collagen helices (each being left-handed).
- twin h. SYN: Watson-Crick h..
- Watson-Crick h. the helical structure assumed by two strands of deoxyribonucleic acid, held together throughout their length by hydrogen bonds between bases on opposite strands, referred to as Watson-Crick base pairing. See base pair. SYN: DNA h., double h., twin h..

* * *

he·lix 'hē-liks n, pl he·li·ces 'hel-ə-.sēz, 'hē-lə- also he·lix·es 'hē-lik-səz
1) the incurved rim of the external ear
2) a curve traced on a cylinder by the rotation of a point crossing its right sections at a constant oblique angle broadly SPIRAL (2) see ALPHA-HELIX, DOUBLE HELIX

* * *

n.
the outer curved fleshy ridge of the pinna of the outer ear.

* * *

He·lix (heґliks) a genus of snails of the family Helicidae, including some of the common garden snails.

Medical dictionary. 2011.

Synonyms:

Look at other dictionaries:

  • hélix — hélix …   Dictionnaire des rimes

  • Helix — ? Helix …   Википедия

  • hélix — [ eliks ] n. m. • 1690; gr. helix « spirale » 1 ♦ Anat. Ourlet du pavillon de l oreille, décrivant un demi cercle en partant de la conque jusqu à la partie supérieure du lobule. 2 ♦ Zool. Escargot. ● hélix nom masculin (latin scientifique helix,… …   Encyclopédie Universelle

  • Helix SF — is a quarterly American speculative fiction online magazine edited by William Sanders and Lawrence Watt Evans. The poetry editor is Bud Webster.Sanders began the magazine as a place where writers could publish things that none of the regular… …   Wikipedia

  • helix — HÉLIX s.n. (anat.) Margine a pavilionului urechii. [< fr. hélix, cf. gr. helix]. Trimis de LauraGellner, 20.04.2005. Sursa: DN  HÉLIX s. n. margine a pavilionului urechii. (< fr. hélix) …   Dicționar Român

  • hélix — m. anat. Repliegue semicircular en el borde del pabellón de la oreja. Medical Dictionary. 2011. hélix repliegue semicircular que forma el …   Diccionario médico

  • helix — helix; helix·in; helix·om·e·ter; su·per·helix; …   English syllables

  • Helix — He lix, n.; pl. L. {Helices}, E. {Helixes}. [L. helix, Gr. ?, ?, fr. ? to turn round; cf. L. volvere, and E. volute, voluble.] 1. (Geom.) A nonplane curve whose tangents are all equally inclined to a given plane. The common helix is the curve… …   The Collaborative International Dictionary of English

  • Helix — Helix, OR U.S. city in Oregon Population (2000): 183 Housing Units (2000): 68 Land area (2000): 0.114338 sq. miles (0.296135 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.114338 sq. miles (0.296135 sq. km)… …   StarDict's U.S. Gazetteer Places

  • Helix, OR — U.S. city in Oregon Population (2000): 183 Housing Units (2000): 68 Land area (2000): 0.114338 sq. miles (0.296135 sq. km) Water area (2000): 0.000000 sq. miles (0.000000 sq. km) Total area (2000): 0.114338 sq. miles (0.296135 sq. km) FIPS code:… …   StarDict's U.S. Gazetteer Places

  • helix — a spiral thing, 1560s, from L. helix spiral, from Gk. helix (gen. helikos), related to eilein to turn, twist, roll, from PIE *wel ik , from root *wel to turn, revolve (see VULVA (Cf. vulva)) …   Etymology dictionary


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.