Structure and Stability of the α-Helix: Lessons for Design

Errington, Neil; Iqbalsyah, Teuku M.; Doig, Andrew J.

doi:10.1385/1-59745-116-9:3

Cited by 20 publications

(25 citation statements)

References 90 publications

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“…The maximum binding for FROP-1 was around 10-20 min, whereas FROPDOTA reached its maximum at 2-4 h, remaining unchanged for almost 24 h. The fixed a-helix structure of FROPDOTA apparently induces a strong change in secondary structure and constitutes an avid binding conformation of the peptide (14). In contrast, FROP-1 has a more flexible structure.…”

Section: Discussionmentioning

confidence: 95%

Influence of Chelate Conjugation on a Newly Identified Tumor-Targeting Peptide

Mier¹,

Zitzmann²,

Krämer

et al. 2007

Journal of Nuclear Medicine

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The transfer of peptide sequences identified by screening of phage-displayed libraries to clinical application is often difficult. This study investigated whether coupling of a new peptide, FROP-1, to the chelator 1,4,7,10-tetraazacyclododecane-1,4, 7,10-tetraacetic acid (DOTA) resulted in structural restriction and, consequently, improved binding and stability. Methods: The peptide FROP-1 was coupled to the chelator DOTA and labeled with 111 In. The structural changes caused by the addition of the chelator were determined by circular dichroism. The properties of this modified peptide were investigated in in vitro binding assays and monitored for kinetics, competition, and internalization as well as serum stability. A cell-type binding profile was established and the in vivo biodistribution was evaluated in a nude mouse model. Results: When compared with the free peptide without chelator, FROPDOTA revealed different cellular uptake kinetics, reaching a maximum at 2 h in vitro. The cells completely accumulated the tracer, and competition experiments revealed that 99.4% (FRO82-2 cells), 98.6% (MCF-7 cells), or 99.3% (average for 3 primary head and neck tumor cell lines) of tracer accumulation could be suppressed, revealing the specificity of this process. The internalization kinetics determined in MCF-7 cells supported this finding: After an incubation time of 180 min, the major fraction of FROPDOTA was trapped intracellularly. Serum stability experiments revealed an increase in stability due to the chelator, with a half-life of 71 min. Circular dichroism measurements indicated a fixed a-helix structure of FROPDOTA representing a strong change in secondary structure. In competition binding experiments, the binding constant (K D ) to FRO82-2 cells was determined to be 494 nM. Despite this avid binding affinity, the binding kinetics were found to be too slow to induce an uptake in vivo before clearance. Consequently, the biodistribution revealed a rapid renal and hepatobiliary clearance, with blood levels dropping from 5.48 6 0.26 %ID/g (percentage injected dose per gram) 5 min after injection to 0.77 6 0.15 %ID/g at 135 min after injection. Conclusion: This study revealed that peptides that are identified by display techniques may be underrated. Careful alteration of their structure will permit going beyond the possibilities that the limited pool of naturally occurring peptides provide for tumor targeting.

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Section: Discussionmentioning

confidence: 95%

Influence of Chelate Conjugation on a Newly Identified Tumor-Targeting Peptide

Mier¹,

Zitzmann²,

Krämer

et al. 2007

Journal of Nuclear Medicine

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“…α-Helices have very characteristic and intense bands in the far UV-CD [33]: a maximum about 192 nm, and two minima at 208 and 222 nm, so that the α-helix formation can be detected by UV-CD even at relatively low populations. A wellestablished method to quantify α-helix content (f H ; [34]) is based on the intensity of the 222 being n the number of residues, and T the temperature in ºC.…”

Section: Circular Dichroismmentioning

confidence: 99%

“…On the following, we are going to give a brief overview of the contributions to α-helix stability, which are useful as guidelines to design α-helical peptides. Further details can be found on previous reviews about α-helical peptides [34,[101][102][103][104][105][106][107][108] and the references therein.…”

Section: Contributions To α-Helix Stabilitymentioning

confidence: 99%

Design and structural characterisation of monomeric water-soluble α-helix and β-hairpin peptides: State-of-the-art

Morales

Jiménez

2019

Archives of Biochemistry and Biophysics

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Highlights α-helix and β-hairpin peptides are models for protein folding and stability Guidelines to design stable α-helical and β-hairpin-forming peptides are available Peptide structures are characterised by spectroscopic techniques, mainly CD and NMR Peptide structures are modulated and even modified by the environment Current peptide design aims to get improved bioactivity or novel biomaterials

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“…Figure 1a shows the helical wheel projection of temporin-SHf. Spatial proximity of residues in the helical conformation can be utilized to incorporate the cysteine disulfide (Errington, Iqbalsyah, & Doig, 2006;Indu et al, 2010;Venkatraman, Shankaramma, & Balaram, 2001). The residues at i/i + 4 and i/i + 3 position in the helical sequence are proximal which can be mutated with cysteine disulfides to stabilize the helical conformation.…”

Section: Stability Of Temporin-shf and [L4cmentioning

confidence: 99%

Disulfide engineering on temporin‐SHf: Stabilizing the bioactive conformation of an ultra‐short antimicrobial peptide

et al. 2019

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In Silico searching for short antimicrobial peptides has revealed temporin‐SHf as the short (8AA), hydrophobic, broad spectrum, and natural antimicrobial peptide. Important drawback associated with temporin‐SHf is the susceptibility of its bioactive conformation for denaturation and proteolytic degradation. In the current report, disulfide engineering strategy has been adopted to improve the stability of bioactive conformation of temporin‐SHf. The functionally non‐critical Leu4 and Ile7 residues at i and i + 3 position of helical conformation of temporin‐SHf were mutated with cysteine disulfide. Designed [L4C, I7C]temporin‐SHf was synthesized, characterized using NMR spectroscopy, and accessed for antimicrobial activity. [L4C, I7C]Temporin‐SHf adopts helical conformation from Phe3 to Phe8 in the absence of membrane‐mimetic environment and retains broad spectrum antimicrobial activity. The reduction potential of cysteine disulfide of [L4C, I7C]temporin‐SHf is −289 mV. Trypsin‐induced digestion and serum‐induced digestion have confirmed the advantage of cysteine disulfide in imparting proteolytic stability to temporin‐SHf. Disulfide‐stabilized temporin‐SHf may serve as a good model for the rational design of temporin‐SHf based antibiotics for treatment of infectious diseases.

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Structure and Stability of the α-Helix: Lessons for Design

Cited by 20 publications

References 90 publications

Influence of Chelate Conjugation on a Newly Identified Tumor-Targeting Peptide

Influence of Chelate Conjugation on a Newly Identified Tumor-Targeting Peptide

Design and structural characterisation of monomeric water-soluble α-helix and β-hairpin peptides: State-of-the-art

Disulfide engineering on temporin‐SHf: Stabilizing the bioactive conformation of an ultra‐short antimicrobial peptide

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