Applications of Circular Dichroism for Structural Analysis of Gelatin and Antimicrobial Peptides

Gopal, Ramamourthy; Park, Jin Soon; Seo, Chang Ho; Park, Yoonkyung

doi:10.3390/ijms13033229

Cited by 99 publications

(75 citation statements)

References 71 publications

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“…Although Gopal et al 47 reported some specific conformations of gelatin, we observed no specific conformation. This result was consistent with a previous report by Zhang et al 48 The almost identical spectra of unmodified and phosphonated gelatin demonstrated that phosphonation did not induce a conformational change in the gelatin.…”

Section: Preparation Of Phosphonated Gelatincontrasting

confidence: 54%

Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

Zhou¹,

Park²,

Mao³

et al. 2015

IJN

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Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by 31 P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface.

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Section: Preparation Of Phosphonated Gelatincontrasting

confidence: 54%

Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

Zhou¹,

Park²,

Mao³

et al. 2015

IJN

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“…Additionally, the observed CD spectra of EuP-82 containing 10 mM ZnCl 2 showed a negative peak at 205 nm. This negative peak referred to a random coil conformation [24]. Increasing the random coil markedly indicated the functional structure destroyed, which leads to the decrease of enzyme activity [25].…”

Section: Resultsmentioning

confidence: 99%

The Effects of Metal Ions in Euphorbia cf. lactea Latex on the Fibrinogenolytic Activity of a Plant Protease

Siritapetawee

Limphirat

Kantachot

et al. 2014

Appl Biochem Biotechnol

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Two synchrotron-based techniques, synchrotron X-ray fluorescence (SXRF) and X-ray absorption spectroscopy (XAS), have demonstrated that Ca(2+) and Zn(2+) were the major metal ions distributed in the natural latex of Euphorbia cf. lactea. Both metal ions were found to affect the fibrinogenolytic activity of a homodimeric protease purified from the latex of this plant. The dimeric protein had an estimated molecular mass of about 82 kDa analyzed by SDS-PAGE. Therefore this protein was called as EuP-82. Based on the results of circular dichroism (CD) spectroscopy and the fibrinolytic activity measurement, it was found that Ca(2+) could activate the proteolytic activity of the enzyme by stabilizing its backbone structure. The intact conformation of EuP-82 was predicted from CD spectrum, which consisted of 51 % α-helix and 9 % β-sheet. Zn(2+) (10 mM) could decrease the fibrinolytic activity of EuP-82 to 30 ± 1 %. CD spectrum also supported that the inhibitory effect of Zn(2+) on the enzyme activity occurred by the drastic change of the enzyme structure with increasing the random coil conformation and by switching between α-helix and β-sheet structure. These results could be of first importance for further application to use EuP-82, the natural source protease as a potential drug for the thrombosis treatment. The fibrinolytic activity of EuP-82 may be enhanced by plasma Ca(2+) which generally involves in human hemostasis system.

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“…4a), but the secondary structures of AMPS can change depending on the membrane composition, assuming α-helical, β-sheet or random coil conformations. To determine whether the secondary structures of myxinidin2 and myxinidin3 varied with membrane type, we used CD spectroscopy to determine the peptide structures in the presence of PG, PE:PG (7:3, w/w), PC, PC:CH (2:1, w/w), PC:SM (2:1, w/w), and SM liposomes, which mimic bacterial and mammalian cell membranes (Gopal et al 2012). The analogs showed α-helical and β-sheet secondary structures in bacterial bilayers composed of PG or PE:PG (Cantisani et al 2013); however, they exhibited a random coil structure in bilayers mimicking RBCs (PC:CH) and mammalian cells (PC, PC:SM, SM) (Fig.…”

Section: Discussionmentioning

confidence: 99%

Design and membrane-disruption mechanism of charge-enriched AMPs exhibiting cell selectivity, high-salt resistance, and anti-biofilm properties

2015

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Cationic antimicrobial peptides (AMPs) are essential components of the innate immune system, offering protection against invading pathogenic bacteria. In nature, AMPs serve as antibiotics with broad-spectrum antimicrobial and anti-biofilm properties. However, low effective stability in high-salt environments and physiological instability in biological membranes limit the applicability of naturally occurring AMPs as novel therapeutics. We therefore designed short synthetic cationic peptides by substituting key residues in myxinidin, an AMP derived from the epidermal mucus of hagfish, with lysine (Lys, K), arginine (Arg, R), and tryptophan (Trp, W). The resultant myxinidin analogs exhibited strong antimicrobial activity against both Gram-positive and Gram-negative bacteria, including multidrug-resistant strains, even under high-salt conditions. Moreover, these peptides showed high binding affinity for both lipopolysaccharides and lipoteichoic acids and inhibited biofilm formation by most bacteria, but did not cause significant lysis of human red blood cells and were not cytotoxic to normal human keratinocytes. Circular dichroism analysis revealed that myxinidin and its analogs assumed α-helical or β-sheet structures within artificial liposomes and bacterial membranes. In addition, bacterial killing and membrane permeation experiments demonstrated that the myxinidin analogs permeated through bacterial membranes, leading to cytoplasmic disruption and cell death. Taken together, these findings suggest myxinidin analogs may be promising candidate antibiotic agents for therapeutic application against antibiotic-resistant bacteria.

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Applications of Circular Dichroism for Structural Analysis of Gelatin and Antimicrobial Peptides

Cited by 99 publications

References 71 publications

Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

The Effects of Metal Ions in Euphorbia cf. lactea Latex on the Fibrinogenolytic Activity of a Plant Protease

Design and membrane-disruption mechanism of charge-enriched AMPs exhibiting cell selectivity, high-salt resistance, and anti-biofilm properties

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