A Reversible Transition between an α‐Helix and a 3<sub>10</sub>‐Helix in a Fluorescence‐Labeled Peptide

Hungerford, Graham; Martinez‐Insua, Marta; Birch, David J. S.; Moore, Barry D.

doi:10.1002/anie.199603261

Cited by 41 publications

(27 citation statements)

References 28 publications

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“…From these results it is clear that a large proportion of secondary structure is formed very quickly (within disulphide cyclic peptides of various lengths containing a proline residue [32]. that stable protein fragments or designed peptides could form the basis of "molecular switching" devices [86,87]. The study of protein fragments could also provide insights into some of the early stages in protein folding, since such fragments could act as nuclei for directing further folding [88] (see Section 4.3).…”

Section: The Nature Of Early Folding Intermediatesmentioning

confidence: 98%

The Use of Circular Dichroism in the Investigation of Protein Structure and Function

Kelly

Price²

2000

CPPS

976

707

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Circular Dichroism (CD) relies on the differential absorption of left and right circularly polarised radiation by chromophores which either possess intrinsic chirality or are placed in chiral environments. Proteins possess a number of chromophores which can give rise to CD signals. In the far UV region (240-180 nm), which corresponds to peptide bond absorption, the CD spectrum can be analysed to give the content of regular secondary structural features such as α-helix and β-sheet. The CD spectrum in the near UV region (320-260 nm) reflects the environments of the aromatic amino acid side chains and thus gives information about the tertiary structure of the protein. Other non-protein chromophores such as flavin and haem moieties can give rise to CD signals which depend on the precise environment of the chromophore concerned. Because of its relatively modest resource demands, CD has been used extensively to give useful information about protein structure, the extent and rate of structural changes and ligand binding. In the protein design field, CD is used to assess the structure and stability of the designed protein fragments. Studies of protein folding make extensive use of CD to examine the folding pathway; the technique has been especially important in characterising "molten globule" intermediates which may be involved in the folding process. CD is an extremely useful technique for assessing the structural integrity of membrane proteins during extraction and characterisation procedures. The interactions between chromophores can give rise to characteristic CD signals. This is well illustrated by the case of the light harvesting complex from photosynthetic bacteria, where the CD spectra can be analysed to indicate the extent of orbital overlap between the rings of bacteriochlorophyll molecules. It is therefore evident that CD is a versatile technique in structural biology, with an increasingly wide range of applications.

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Section: The Nature Of Early Folding Intermediatesmentioning

confidence: 98%

The Use of Circular Dichroism in the Investigation of Protein Structure and Function

Kelly

Price²

2000

CPPS

976

707

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“…25 Both are right-handed helices but they are stabilized by different H-bonding patterns. 26 The a-as well as the 3 10 -helix are conformations in which the polar carbonyl groups are oriented parallel to the peptide backbone. 27 These peptides exhibit large dipole moments with the negative dipole end at the C-terminus.…”

Section: A-/3 10 -Helical Peptidesmentioning

confidence: 99%

The influence of dipole moments on the mechanism of electron transfer through helical peptides

Lauz

Eckhardt

Fromm

et al. 2012

Phys. Chem. Chem. Phys.

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The life time of aromatic radical cations is limited by reactions like b-elimination, dimerization, and addition to the solvent. Here we show that the attachment of such a radical cation to the C-terminal end of an a-/3 10 -helical peptide further reduces its life time by two orders of magnitude. For PPII-helical peptides, such an effect is only observed if the peptide contains an adjacent electron donor like tyrosine, which enables electron transfer (ET) through the peptide. In order to explain the special role of a-/3 10 -helical peptides, it is assumed that the aromatic radical cation injects a positive charge into an adjacent amide group. This is in accord with quantum chemical calculations and electrochemical experiments in the literature showing a decrease in the amide redox potentials caused by the dipole moments of long a-/3 10 -helical peptides. Rate measurements are in accord with a mechanism for a multi-step ET through a-/3 10 -helical peptides that uses the amide groups or H-bonds as stepping stones.

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“…11,13 A limited number of early attempts were reported where a few peptides of markedly different length and sequence were prepared and shown to effectively undergo this process, induced either by heating or changing the solvent properties. [34][35][36][37] To drastically simplify the complex issue of peptide sequence and length, we decided to concentrate our study on homo-peptides based on C a -tetrasubstituted a-amino acids.…”

Section: Introductionmentioning

confidence: 99%

First homo‐peptides undergoing a reversible 3₁₀‐helix/α‐helix transition: Critical main‐chain length

Moretto

Formaggio

Kaptein³

et al. 2008

Biopolymers

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The difference in length between the more elongated peptide 3(10)-helix and the more compact alpha-helix is about 0.4 A/residue. This property makes the 3(10)-/alpha-helix reversible conversion very promising as a molecular switching tool between the N- and C-terminal functions of a peptide backbone. In this work, using homo-peptides of various main-chain length, all based on the strongly helicogenic, Calpha-tetrasubstituted alpha-amino acid Calpha-methyl-L-valine, we show that a well defined, solvent controlled, reversible 3(10)-/alpha-helix transition takes place even in a homo-oligomer as short as a terminally blocked hexapeptide. Homo-peptide sequences blocked as a urethane or an acetamide at the N-terminus and as a methyl ester or an N-alkyl amide at the C-terminus are all appropriate. The nature of the occurring helical species in the various solvents tested was assessed by electronic or vibrational circular dichroism.

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A Reversible Transition between an α‐Helix and a 3₁₀‐Helix in a Fluorescence‐Labeled Peptide

Cited by 41 publications

References 28 publications

The Use of Circular Dichroism in the Investigation of Protein Structure and Function

The Use of Circular Dichroism in the Investigation of Protein Structure and Function

The influence of dipole moments on the mechanism of electron transfer through helical peptides

First homo‐peptides undergoing a reversible 3₁₀‐helix/α‐helix transition: Critical main‐chain length

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A Reversible Transition between an α‐Helix and a 310‐Helix in a Fluorescence‐Labeled Peptide

Cited by 41 publications

References 28 publications

The Use of Circular Dichroism in the Investigation of Protein Structure and Function

The Use of Circular Dichroism in the Investigation of Protein Structure and Function

The influence of dipole moments on the mechanism of electron transfer through helical peptides

First homo‐peptides undergoing a reversible 310‐helix/α‐helix transition: Critical main‐chain length

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Product

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A Reversible Transition between an α‐Helix and a 3₁₀‐Helix in a Fluorescence‐Labeled Peptide

First homo‐peptides undergoing a reversible 3₁₀‐helix/α‐helix transition: Critical main‐chain length