(a.) Of or pertaining to, or in the form of, a helix; spiral; as, a helical staircase; a helical spring.
Example Sentences:
(1) The distribution of the amino acid pairs, i, i + 1 in alpha-helical configurations does not differ from the random pairing.
(2) An analysis of the triple helical stabilities of these cleavage site regions as reflected by their imino acid contents fails to yield a correlation between reactivity and triple helical stability.
(3) The Helical structures of d(C-G-C-A-m5C-G-T-G-m5C-G), d(m5C-G-C-A-m5C-G-T-G-C-G) and d(C-2aminoA-C-G-T-G) were studied in aqueous solution at various salt concentrations and temperatures by 1H-NMR spectroscopy.
(4) Chloride caused a significant concentration-dependent shortening of myosin rods due to destabilization of the alpha-helical double coiled rod structure.
(5) The poly(dG-dC) helical duplex forms a modified, B-family structure (B*) at very high hydration and a normal B structure at slightly lower hydration.
(6) Pretreatment with a novel CRF antagonist, alpha-helical CRF9-41 (130.9 nmol i.t.v.
(7) The melting profile exhibited two transitions--one at about 35 degrees C and one above 50 degrees C. Our spectral data showed that helices I and II were stable during the first transition, and agreed with other data that helix III was the most likely helix to have melted.
(8) (1974)88, 857-872, 873-894] for predicting secondary structure from amino acid sequence have been applied to five predominantly helical membrane-associated peptides.
(9) The alpha-helical content of the free form of the lipoprotein was measured from the circular dichroism spectrum of the lipoprotein in 0.01% sodium dodecyl sulfate and found to be 87%.
(10) In these discoidal complexes, the alpha-helical content was estimated to be 65%, with the rest of the structure being essentially unordered.
(11) A modified plot accounting for amphiphilic helices indicates 5-6 such alpha-segments.
(12) The inactivation of exogenous and neural norepinephrine (NE) by helical strips of rat tail artery was studied with a combination of the techniques of transmural stimulation and oil immersion.
(13) The above analysis suggests that in aqueous solution the protein is devoid of alpha-helical and beta-conformations but that it contains a significant amount of turns.
(14) These results are consistent with a structural model for the membrane in which the peptide chains vary greatly in the proportion of helical segments and polar regions which they contain.
(15) The latter, which is external and solvent accessible, is associated with a distortion in the alpha-helix centered around Tyr33 which consists of a significant increase in the CO(i-4)-N(i) and CO(i-4)-NH(i) distances relative to those in the rest of the helix, as well as a significant departure in the phi, psi angles of Tyr33 relative to regular helical geometry.
(16) Eight alpha-helices behave as relatively rigid bodies and corner regions are more flexible, showing larger fluctuations.
(17) It is suggested that the alpha-helical region, situated in the region between residues 10 and 20, binds to the RNA during assembly of the virus particle.
(18) Considering the density of helices along the RNA, it is not unexpected to find that all these sites lie in helical regions.
(19) Most double-helical segments were reactive to cobra venom ribonuclease to some degree; the exceptions were the five "long-range" helices that are probably compactly folded within the structure.
(20) The angle obtained for the C alpha-D resonance was consistent with a single-stranded beta 6.3-helical model for the backbone but not with double-helical models.
Helix
Definition:
(n.) A nonplane curve whose tangents are all equally inclined to a given plane. The common helix is the curve formed by the thread of the ordinary screw. It is distinguished from the spiral, all the convolutions of which are in the plane.
(n.) A caulicule or little volute under the abacus of the Corinthian capital.
(n.) The incurved margin or rim of the external ear. See Illust. of Ear.
(n.) A genus of land snails, including a large number of species.
Example Sentences:
(1) The presence of a few key residues in the amino-terminal alpha-helix of each ligand is sufficient to confer specificity to the interaction.
(2) The elongation of helix III with the addition of helix II at the N-terminus somewhat stabilizes the ordered structure.
(3) The C-terminal sequence contains an amphiphilic alpha-helix of four turns which lies on the surface of the beta-barrel.
(4) The chiral intercalators, at micromolar concentrations, inhibit the reaction of EcoRI, but for each enantiomeric pair it is the lambda enantiomer, which binds only poorly to a B-DNA helix, that inhibits EcoRI preferentially.
(5) The melting profile exhibited two transitions--one at about 35 degrees C and one above 50 degrees C. Our spectral data showed that helices I and II were stable during the first transition, and agreed with other data that helix III was the most likely helix to have melted.
(6) The helix axes, penetrating the hydrophobic region of the bilayers, were oriented neither parallel nor perpendicular to the membrane normal.
(7) The structure of the Z-helix antigen was confirmed by circular dichroism (CD) and U.V.
(8) Conformational predictions based on these sequences confirm their structural homology and indicate the probable existence of two beta-turns, one beta-chain and a long alpha-helix in them.
(9) The nogalose and aminoglucose sugars lie in the minor and major grooves, respectively, of the distorted B-DNA double helix.
(10) The latter, which is external and solvent accessible, is associated with a distortion in the alpha-helix centered around Tyr33 which consists of a significant increase in the CO(i-4)-N(i) and CO(i-4)-NH(i) distances relative to those in the rest of the helix, as well as a significant departure in the phi, psi angles of Tyr33 relative to regular helical geometry.
(11) The AFB1 moiety is face-stacked in the major groove with its long axis approximately perpendicular to the helix axis.
(12) MP8 also was conformed as an alpha-helix, but was amphipatic in the sense that the N-terminal half of the molecule was hydrophilic and the C-terminal half hydrophobic.
(13) A lectin, Helix pomatia agglutinin (HPA), was planted at the surface of rat GEN by the perfusion of the isolated left kidney with neuraminidase (NRD) and HPA.
(14) As a basis for the discussion a possible structure for the DNA complex of the phenylated neutral red is considered in which the extra phenyl ring at N-5 of the phenazinium system, protrudes into the large groove of the DNA helix while the tricyclic part of the ligand is inserted between the DNA base-pairs.
(15) The opsin mutations included reversal of a charged pair conserved in all G protein-coupled receptors at the cytoplasmic border of the third transmembrane helix (mutant CD1), replacement of 13 amino acids in the second cytoplasmic loop (mutant CD2), and deletion of 13 amino acids from the third cytoplasmic loop (mutant EF1).
(16) The remaining 26 independently isolated second-site suppressor mutations all mapped within the amino-terminal DNA binding domain of LexA, at positions 22 (situated in the turn between helix 1 and helix 2) and positions 57, 59, 62, 71 and 73.
(17) In subsequent steps, unassociated Y' directs the synthesis of the complementary oligopurine (R') strand forming a new double helix Y'R' that may direct the synthesis of an oligopyrimidine strand, Y, that is expected to be identical to the first strand that started the whole sequence.
(18) Z-DNA antigen was prepared against poly(dG-dC).poly(dG-dC), which had been converted to the Z-helix conformation in high salt and then stabilized by bromination.
(19) Incubation and heating of the polymers in 1 mM Mn2+ caused the spectral shift reported for the left-handed Z-DNA conformation in the alternating copolymer and the change reported for the triple helix in the homopolymer.
(20) To investigate the ability of a protein to accommodate potentially destabilizing amino acid substitutions, and also to investigate the steric requirements for catalysis, proline was substituted at different sites within the long alpha-helix that connects the amino-terminal and carboxyl-terminal domains of T4 lysozyme.