Comparative Study of Chicken and Human Parathyroid Hormone‐(1–34)‐Peptides in Solution with SDS

Kanaori, Kenji; Takai, Makoto; Nosaka, Atsuko Y.

doi:10.1111/j.1432-1033.1997.00878.x

Cited by 11 publications

(9 citation statements)

References 52 publications

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“…Low concentrations of detergent promote the formation of a b structure in the peptide. At concentrations below its cmc, SDS often promotes b-sheet structure (Zhong and Johnson 1992;Waterhous and Johnson 1994), and a similar behavior was previously observed in our and other laboratories for other nonfibrillogenic peptides (Bairaktari et al 1990;Kanaori et al 1997). Above the cmc (;8 mM), asyn57-102 specifically interacts with SDS micelles and adopts a helical conformation.…”

Section: Resultssupporting

confidence: 88%

Structure and topology of the non‐amyloid‐β component fragment of human α‐synuclein bound to micelles: Implications for the aggregation process

et al. 2006

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Human a-synuclein is a small soluble protein abundantly expressed in neurons. It represents the principal constituent of Lewy bodies, the main neuropathological characteristic of Parkinson's disease. The fragment corresponding to the region 61-95 of the protein, originally termed NAC (non-amyloid-b component), has been found in amyloid plaques associated with Alzheimer's disease, and several reports suggest that this region represents the critical determinant of the fibrillation process of a-synuclein. To better understand the aggregation process of a-synuclein and the role exerted by the biological membranes, we studied the structure and the topology of the NAC region in the presence of SDS micelles, as membrane-mimetic environment. To overcome the low solubility of this fragment, we analyzed a recombinant polypeptide corresponding to the sequence 57-102 of a-synuclein, which includes some charged amino acids flanking the NAC region. Three distinct helices are present, separated by two flexible stretches. The first two helices are located closer to the micelle surface, whereas the last one seems to penetrate more deeply into the micelle. On the basis of the structural and topological results presented, a possible pathway for the aggregation process is suggested. The structural information described in this work may help to identify the appropriate target to reduce the formation of pathological a-synuclein aggregation.

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Section: Resultssupporting

confidence: 88%

Structure and topology of the non‐amyloid‐β component fragment of human α‐synuclein bound to micelles: Implications for the aggregation process

et al. 2006

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“…6C). These wavelength maxima are consistent with a location of the fluorophores within the hydrophobic core of the SDS micelles (46,47). Following transfer into the lipid environment the fluorescence quantum yield was increased 1.4 -2.6-fold for all of the fragments and eBO (Fig.…”

Section: Preparation and Reconstitution Of Br Polypeptide Fragments-esupporting

confidence: 79%

Secondary Structure of Bacteriorhodopsin Fragments

Lüneberg

Widmann

Dathe³

et al. 1998

Journal of Biological Chemistry

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The secondary structure of bacteriorhodopsin polypeptides comprising two (AB, CD, DE, FG), three (AC, CE, EG), four (AD, DG), or five (AE, CG) of the seven transmembrane segments has been analyzed by circular dichroism spectroscopy. A comparison of the ␣-helix content with that predicted from the high resolution structure of the native protein revealed that the N-terminal AB, AC, AD, and AE fragments and the C-terminal CG fragment are completely refolded in the presence of mixed phospholipid micelles. In contrast, the DG, EG, FG, CD, CE, and DE fragments did not form ␣-helices of the expected lengths at pH 6. Each of the latter fragments displayed, however, an increased helicity upon lowering the pH to 4. Fluorescence measurements with the CD and FG fragments suggest that this helix formation occurs within transmembrane segments C and G, respectively, and thus is likely to originate from the protonation of carboxyl residues that participate in proton translocation. The partial misfolding at neutral pH observed for the shorter fragments from the central and C-terminal part of bacteriorhodopsin indicates that the conformation of some transmembrane segments is specified by interactions with neighboring helices in the assembled structure. Moreover, the data demonstrate that two stable helices at the N terminus of a multihelical membrane protein are sufficient as a folding template to induce a native conformation to the following transmembrane domains.Integral membrane proteins generally adopt a regular secondary structure within the lipid bilayer in order to satisfy hydrogen bonding of the peptide backbone in a hydrophobic environment. The physicochemical constraints imposed by the membrane limit the variety of basic protein architectures, and structure prediction is thus expected to be much simpler than for globular proteins. This characteristic has been exploited in the development of different algorithms for the identification of membrane protein secondary structure (1-3). Transmembrane (TM) 1 helices represent the predominant structural element and can be predicted with high reliability by scanning the protein sequence for regions of adequate length and hydrophobicity to span the lipid bilayer in an ␣-helical conformation. One such algorithm identifies TM ␣-helices based on an estimate of the free energy of transferring a helical segment from the aqueous environment into a lipid bilayer (3). These thermodynamic calculations predict that the individual TM ␣-helix should be stable, even in the absence of interactions with other parts of the molecule. The folding and assembly of multihelical membrane proteins could thus proceed according to a sequential two-step mechanism, in which the individual TM helices form during the initial membrane insertion step, and subsequently associate to form the native tertiary structure (4, 5). Direct structural studies on integral membrane proteins are hindered by the difficulty in obtaining crystals suitable for x-ray diffraction, and by their restricted motion in the lipid enviro...

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“…The far UV region of the CD spectrum has been explored in this study in order to determine the effect of stabiliser (trehalose and Brij 97) on the secondary structure of PTH (1-34) following particle engineering. Reports from previous CD studies revealed that PTH (1-34) has an α-helical secondary structure (22,23). The result obtained from unprocessed PTH (1-34) is consistent with the published CD data for PTH in the far UV spectrum.…”

Section: Circular Dichroismsupporting

confidence: 89%

“…CD is a widely used technique in the determination of both the secondary and the tertiary structures of proteins/ peptides (22,23). Information concerning the secondary structures of proteins is normally obtained in the far UV region (190-260 nm) while the near UV region (250-320 nm) gives information about the tertiary structure.…”

Section: Circular Dichroismmentioning

confidence: 99%

The Effects of Excipients and Particle Engineering on the Biophysical Stability and Aerosol Performance of Parathyroid Hormone (1-34) Prepared as a Dry Powder for Inhalation

Shoyele

Sivadas²,

Cryan

2011

AAPS PharmSciTech

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Abstract. Pulmonary delivery of therapeutic peptides and proteins has many advantages including high relative bioavailability, rapid systemic absorption and onset of action and a non-invasive mode of administration which improves patient compliance. In this study, we investigated the effect of spraydrying (SD) and spray freeze-drying processes on the stability and aerosol performance of parathyroid hormone (PTH) (1-34) microparticles. In this study, the stabilisation effect of trehalose (a non-reducing sugar) and Brij 97 (a non-ionic surfactant) on spray-dried PTH particles was assessed using analytical techniques including circular dichroism (CD), fluorescence spectroscopy, modulated differential scanning calorimetry and an in vitro bioactivity assay. Physical characterisation also included electron microscopy, tap density measurement and laser light diffraction. The aerosol aerodynamic performance of the formulations was assessed using the Andersen cascade impactor. Based on these studies, a formulation for spray freeze-drying was selected and the effects of the two particle engineering techniques on the biophysical stability and aerosol performance of the resulting powders was determined. CD, fluorescence spectroscopy and bioactivity data suggest that trehalose when used alone as a stabilising excipient produces a superior stabilising effect than when used in combination with a non-ionic surfactant. This highlights the utility of CD and fluorescence spectroscopy studies for the prediction of protein bioactivity post-processing. Therefore, a method and formulation suitable for the preparation of PTH as a dry powder was developed based on spray-drying PTH with trehalose as a stabiliser with the bioactivity of SD PTH containing trehalose being equivalent to that of unprocessed PTH.

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Comparative Study of Chicken and Human Parathyroid Hormone‐(1–34)‐Peptides in Solution with SDS

Cited by 11 publications

References 52 publications

Structure and topology of the non‐amyloid‐β component fragment of human α‐synuclein bound to micelles: Implications for the aggregation process

Structure and topology of the non‐amyloid‐β component fragment of human α‐synuclein bound to micelles: Implications for the aggregation process

Secondary Structure of Bacteriorhodopsin Fragments

The Effects of Excipients and Particle Engineering on the Biophysical Stability and Aerosol Performance of Parathyroid Hormone (1-34) Prepared as a Dry Powder for Inhalation

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