Characterization of a Lipid Coating on the Surface of Silk Produced by the Embiid Antipaluria urichi

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Description
Insects of the order Embiidina spin sheets of very thin silk fibers from their forelimbs to build silken shelters on bark and in leaf litter in tropical climates. Their shelters are very stiff and hydrophobic to keep out predators and

Insects of the order Embiidina spin sheets of very thin silk fibers from their forelimbs to build silken shelters on bark and in leaf litter in tropical climates. Their shelters are very stiff and hydrophobic to keep out predators and rain. In this study, the existence of an outer lipid coating on silk produced by the embiid Antipaluria urichi is shown using scanning and transmission electron microscopy, FT-IR, and water drop contact angle analysis. Subsequently, the composition of the lipid layer is then characterized by 1H NMR and GC-MS.
Date Created
2014-05
Agent

A Hydrogen (1H) Nuclear Magnetic Resonance (NMR) Method for Amino Acid Analysis

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Description
Amino acid analysis (AAA) of egg white lysozyme and bovine Achilles tendon collagen was performed using 1H solution-state nuclear magnetic resonance (NMR) spectroscopy. The proteins were hydrolyzed in 6M HCL with and without 0.02% phenol at 110\u00B0C for 24, 48,

Amino acid analysis (AAA) of egg white lysozyme and bovine Achilles tendon collagen was performed using 1H solution-state nuclear magnetic resonance (NMR) spectroscopy. The proteins were hydrolyzed in 6M HCL with and without 0.02% phenol at 110\u00B0C for 24, 48, and 72 hours. For both proteins, 18 of 20 amino acids were characterized including hydroxyproline and hydroxylysine in collagen, using 1-dimensional (1D) and 2-dimensional (2D) NMR spectroscopy experiments. Errors ranging from <1% to 8% were seen in treatments with and without phenol. Both proteins could be correctly identified within their own species using the online database search AACompIdent. The proposed approach is a simple analytical technique that does not require the use of column separation or amino acid derivatization prior to compositional analysis.
Date Created
2014-05
Agent

Investigating beta-sheet nanocrystal ordering and correlation with small-angle X-ray scattering

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Description
In disordered soft matter system, amorphous and crystalline components might be coexisted. The interaction between the two distinct structures and the correlation within the crystalline components are crucial to the macroscopic property of the such material. The spider dragline silk

In disordered soft matter system, amorphous and crystalline components might be coexisted. The interaction between the two distinct structures and the correlation within the crystalline components are crucial to the macroscopic property of the such material. The spider dragline silk biopolymer, is one of such soft matter material that exhibits exceptional mechanical strength though its mass density is considerably small compare to structural metal. Through wide-angle X-ray scattering (WAXS), the research community learned that the silk fiber is mainly composed of amorphous backbone and $\beta$-sheet nano-crystals. However, the morphology of the crystalline system within the fiber is still not clear. Therefore, a combination of small-angle X-ray scattering experiments and stochastic simulation is designed here to reveal the nano-crystalline ordering in spider silk biopolymer. In addition, several density functional theory (DFT) calculations were performed to help understanding the interaction between amorphous backbone and the crystalline $\beta$-sheets.

By taking advantage of the prior information obtained from WAXS, a rather crude nano-crystalline model was initialized for further numerical reconstruction. Using Markov-Chain stochastic method, a hundreds of nanometer size $\beta$-sheet distribution model was reconstructed from experimental SAXS data, including silk fiber sampled from \textit{Latrodectus hesperus}, \textit{Nephila clavipes}, \textit{Argiope aurantia} and \textit{Araneus gemmoides}. The reconstruction method was implemented using MATLAB and C++ programming language and can be extended to study a broad range of disordered material systems.
Date Created
2015
Agent

Elucidating Proline Dynamics in Spider Dragline Silk Fibre Using 2H–13C HETCOR MAS NMR

Description

2H–13C HETCOR MAS NMR is performed on 2H/13C/15N-Pro enriched A. aurantia dragline silk. Proline dynamics are extracted from 2H NMR line shapes and T1 in a site-specific manner to elucidate the backbone and side chain molecular dynamics for the MaSp2

2H–13C HETCOR MAS NMR is performed on 2H/13C/15N-Pro enriched A. aurantia dragline silk. Proline dynamics are extracted from 2H NMR line shapes and T1 in a site-specific manner to elucidate the backbone and side chain molecular dynamics for the MaSp2 GPGXX β-turn regions for spider dragline silk in the dry and wet, supercontracted states.

Date Created
2014-03-24
Agent