A small-angle X-ray scattering study of the structure of lysozyme–sodium dodecyl sulfate complexes

Narayanan, Janaky; Rasheed, A. S. Abdul; Bellare, Jayesh

doi:10.1016/j.jcis.2008.09.012

Cited by 23 publications

(22 citation statements)

References 43 publications

(68 reference statements)

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“…In contrast with the work of Narayanan et al, [22] the SAXS data presented for the 50 mM SDS sample in this work show an additional upturn in the SAXS at q < 0.25 nm…”

Section: Resultscontrasting

confidence: 99%

“…The SAXS curve obtained for the pure SDS sample is qualitatively similar to that reported by Narayanan et al for a 70 mM SDS solution in water. [22] Their scattering curves were modelled assuming that the micelles adopt a prolate ellipsoidal shape of ca. 3.3 2.3 nm with a core-shell type morphology in which the electron density of the core (composed of the hydrocarbon chains) is less than that of water and that the shell (composed of the SDS head groups; 0.65 nm thick) has a greater electron density than the solvent.…”

Section: Resultsmentioning

confidence: 99%

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Cyclic Enones as Substrates in the Morita–Baylis–Hillman Reaction: Surfactant Interactions, Scope and Scalability with an Emphasis on Formaldehyde

et al. 2009

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Traditionally, cyclic enones and formalin are reactants notorious for displaying problematic behaviour (i.e., poor solubility and low yields) under Morita-Baylis-Hillman (MBH) reaction conditions. The body of research presented herein focuses on the use of surfactants in water as a solvent medium that offers a resolution to many of the issues associated with the MBH reaction. Reaction scope, scalability and small angle X-ray scattering have been studied to assist with the understanding of the reaction mechanism and industrial application. A comparison against known literature methods for reaction scale-up is also discussed.

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“…In contrast with the work of Narayanan et al, [22] the SAXS data presented for the 50 mM SDS sample in this work show an additional upturn in the SAXS at q < 0.25 nm…”

Section: Resultscontrasting

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Cyclic Enones as Substrates in the Morita–Baylis–Hillman Reaction: Surfactant Interactions, Scope and Scalability with an Emphasis on Formaldehyde

et al. 2009

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“…Interestingly, α of PCN1 and PCN2 nanofibers is calculated to be 3 and 4, respectively (Table ), from Porod's law ( I ( q )∝ q −3 or q −4 ) and suggested a nonfractal structure that has even interfaces. However, the slope of the data of PCN0 and PCN5 (Figure c) is 3.5 and 3.4, respectively, which corresponds to a surface fractal structure that has dimensions ( D s ) of 2.5 and 2.6 ( α =6− K s ) . In summary, the SAXS results agree with the observed nanofiber micrographs and suggested the possibility of a high charge transfer in PCN1 nanofibers during electrochemical reactions.…”

Section: Resultssupporting

confidence: 76%

Enriched Doping Level and Tuned Fiber Fractal Dimensions in Nonwoven Carbon‐Doped Polyaniline for Efficient Solid‐State Supercapacitors

2016

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Nonwoven fibrous mats of polyaniline/carbon black on conducting substrates are synthesized through a two‐step oxidative process. Adsorbed and catalyzed aniline monomers in the synthesis process improved the doping degree (0.381) in the hybrid fibers. The formation of a porous mat on substrates was confirmed by using electron microscopy and small‐angle X‐ray scattering. The fractal dimensions of the fibers are correlated with Porod's law and suggest the presence of a nonfractal structure in the PCN1 mat. The hybrid mat exhibited a high porosity and effective surface area, even interfaces, and conductive pathways for the electrode/electrolyte to improve the kinetic process. Electrochemical measurements have been conducted on developed fibers, which showed a high specific capacitance of around 1526 F g−1, excellent cyclic stability, and elevated energy density (212 Wh kg−1) after doping carbon into polyaniline (PANI). Additionally, a symmetric solid‐state supercapacitor device was fabricated, a capacitance around 270 F g−1 was measured, and it was able to light a commercial light‐emitting diode (LED).

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“…These studies indicate that complex formation is driven by electrostatic interactions as well as interactions between exposed hydrophobic patches on the unfolded protein and the surfactant micelles. Other studies of lysozyme (16,17), a-lactalbumin (18), and Acyl-CoAbinding protein (ACBP) (19) with SDS added in different proportions, highlight a variety of complex structures with increasing SDS concentration. At low SDS concentrations, the native ACBP binds a small number of SDS molecules, whereas intermediate SDS concentrations lead to a protein dimer formed around a shared micelle; finally, higher SDS concentrations lead to complexes with only one protein per micelle.…”

Section: Introductionmentioning

confidence: 99%

Myoglobin and α-Lactalbumin Form Smaller Complexes with the Biosurfactant Rhamnolipid Than with SDS

Mortensen

Madsen

Andersen

et al. 2017

Biophysical Journal

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Biosurfactants (BSs) attract increasing attention as sustainable alternatives to petroleum-derived surfactants. This necessitates structural insight into how BSs interact with proteins encountered by current chemical surfactants. Thus, small-angle x-ray scattering (SAXS) has been used for studying the structures of complexes made of the proteins α-Lactalbumin (αLA) and myoglobin (Mb) with the biosurfactant rhamnolipid (RL). For comparison, complexes between αLA and the chemical surfactant sodium dodecyl sulfate (SDS) were also investigated. The SAXS data for pure RL micelles can be described by prolate core-shell structures with a core radius of 7.7 Å and a shell thickness of 12 Å, giving an aggregation number of 11. The small core radius is attributed to RL's complex hydrophobic tail. Data for the αLA-RL complex agree with a 12-molecule micelle with a single protein molecule in the shell. For Mb-RL, the analysis gives complexes of two connected micelles, each containing 10 RL and one protein in the shells. αLA-RL and Mb-RL form surfactant-saturated complexes above 5.6 and 4.7 mM RL, respectively, leaving the remaining RL in free micelles. The SAXS data for SDS agree with oblate-shaped micelles with a core of 20 Å, core eccentricity 0.7, and shell thickness of 5.45 Å, with an aggregation number of 74. The αLA-SDS complexes contain a prolate micelle with a core radius of 11-14 Å and a shell of 8-12 Å with up to 3 αLA per particle and up to 43 SDS per αLA, both considerably larger than for RL. Unlike the RL-protein complexes, the number of surfactant molecules in αLA-SDS complexes increases with surfactant concentration, and saturate at higher surfactant concentrations than αLA-RL complexes. The results highlight how RL and SDS follow similar overall rules of self-assembly and interactions with proteins, but that differences in the strength of protein-surfactant interactions affect the formed structures.

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A small-angle X-ray scattering study of the structure of lysozyme–sodium dodecyl sulfate complexes

Cited by 23 publications

References 43 publications

Cyclic Enones as Substrates in the Morita–Baylis–Hillman Reaction: Surfactant Interactions, Scope and Scalability with an Emphasis on Formaldehyde

Cyclic Enones as Substrates in the Morita–Baylis–Hillman Reaction: Surfactant Interactions, Scope and Scalability with an Emphasis on Formaldehyde

Enriched Doping Level and Tuned Fiber Fractal Dimensions in Nonwoven Carbon‐Doped Polyaniline for Efficient Solid‐State Supercapacitors

Myoglobin and α-Lactalbumin Form Smaller Complexes with the Biosurfactant Rhamnolipid Than with SDS

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