scholarly journals Purification and Characterisation of Two Novel Pigment Proteins from the Carapace of Red Swamp Crayfish (Procambarus clarkii)

Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 35
Author(s):  
Hao Chen ◽  
Hongwu Ji ◽  
Chuang Pan ◽  
Di Zhang ◽  
Weiming Su ◽  
...  
Keyword(s):  
Procambarus Clarkii ◽  
Protein Complexes ◽  
Heating Temperature ◽  
3D Structure ◽  
Colour Change ◽  
Size Exclusion ◽  
Protein Subunit ◽  
Salting Out ◽  
Red Swamp Crayfish ◽  
Β Sheet

Pigment proteins play a vital role in the red colour change of the red swamp crayfish (Procambarus clarkii) shell after cooking. In this study, two red-change-related pigment proteins with molecular weights of approximately 170 and 43 kDa—denoted as F1 and F2, respectively—were purified by ammonium sulphate salting-out and size exclusion chromatography. F1 and F2 entirely comprised homomultimeric protein complexes composed of 21 kDa subunits. LC-MS/MS analysis showed that the 21 kDa protein subunit belonged to the crustacyanin family, named P. clarkii crustacyanin A2 (PcCRA2). The full-length cDNA of PcCRA2 was cloned, which encoded 190 amino acid residues and was highly homologous (91.58%) with Cherax quadricarinatus crustacyanin A. The predicted 3D structure showed that PcCRA2 had a β-barrel structure for pigment encapsulation. The colour change of F1 was first detected at 40 °C, and the red change occurred upon heating above 60 °C. Additionally, with increasing temperature, its β-sheet content increased, and its α-helix content reduced. Correlation analysis showed that the redness value of F1 was significantly related to the heating temperature and the β-sheet content.

PHARMACOKINETICS OF FLORFENICOL AND ITS METABOLITE, FLORFENICOL AMINE, IN RED SWAMP CRAYFISH, PROCAMBARUS CLARKII

2011 ◽  
Vol 35 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Gang-Yi YUE ◽  
Zhi-Xin WU ◽  
Qian YANG ◽  
Yi QU ◽  
Li-Jiao PANG ◽  
...  
Keyword(s):  
Procambarus Clarkii ◽  
Red Swamp Crayfish

Removal of Hydrophobic and Hydrophilic Constituents by Anion Exchange Resin

1999 ◽  
Vol 40 (9) ◽  
pp. 207-214 ◽  
Author(s):  
J.-P. Croué ◽  
D. Violleau ◽  
C. Bodaire ◽  
B. Legube
Keyword(s):  
Molecular Weight ◽  
Anion Exchange ◽  
Water Source ◽  
Atomic Ratio ◽  
Size Exclusion ◽  
Salting Out ◽  
Anion Exchange Resins ◽  
Hydrophilic Character ◽  
Exchange Resins

The objective of this work was to compare the affinity of well characterized NOM fractions isolated from two surface waters with strong (gel matrix and macroporous matrix) and weak anion exchange resins (AER) using batch experiment conditions. The structural characterization of the fraction of NOM has shown that the higher the hydrophilic character, the lower the C/O atomic ratio, the lower the SUVA, the lower the aromatic carbon content and the lower the molecular weight. In general (not always), strong AER was more efficient to remove DOC than weak AER. For the same water source (Suwannee River), the higher the molecular weight of the NOM fraction, the lower the affinity with AER. Increasing the ionic strength favored the removal of the hydrophobic NOM fraction (“salting out” effect) while increasing the pH apparently reduced the removal of the hydrophilic NOM fraction. Results were discussed in terms of size exclusion, adsorption, anion exchange and also hydrophobic/hydrophilic repulsion.

scholarly journals Chemical Synthesis and NMR Solution Structure of Conotoxin GXIA from Conus geographus

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 60
Author(s):  
David A. Armstrong ◽  
Ai-Hua Jin ◽  
Nayara Braga Emidio ◽  
Richard J. Lewis ◽  
Paul F. Alewood ◽  
...  
Keyword(s):  
Solution Structure ◽  
3D Structure ◽  
Voltage Sensor ◽  
Solution Nmr ◽  
Striking Similarity ◽  
Amino Acid Peptide ◽  
Wide Range ◽  
Cone Snails ◽  
Drug Leads ◽  
Β Sheet

Conotoxins are disulfide-rich peptides found in the venom of cone snails. Due to their exquisite potency and high selectivity for a wide range of voltage and ligand gated ion channels they are attractive drug leads in neuropharmacology. Recently, cone snails were found to have the capability to rapidly switch between venom types with different proteome profiles in response to predatory or defensive stimuli. A novel conotoxin, GXIA (original name G117), belonging to the I3-subfamily was identified as the major component of the predatory venom of piscivorous Conus geographus. Using 2D solution NMR spectroscopy techniques, we resolved the 3D structure for GXIA, the first structure reported for the I3-subfamily and framework XI family. The 32 amino acid peptide is comprised of eight cysteine residues with the resultant disulfide connectivity forming an ICK+1 motif. With a triple stranded β-sheet, the GXIA backbone shows striking similarity to several tarantula toxins targeting the voltage sensor of voltage gated potassium and sodium channels. Supported by an amphipathic surface, the structural evidence suggests that GXIA is able to embed in the membrane and bind to the voltage sensor domain of a putative ion channel target.

scholarly journals Investigation on the Molecular and Physicochemical Changes of Protein and Starch of Wheat Flour during Heating

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1419
Author(s):  
Tao Yang ◽  
Pei Wang ◽  
Qin Zhou ◽  
Xiao Wang ◽  
Jian Cai ◽  
...  
Keyword(s):  
Wheat Flour ◽  
Heating Temperature ◽  
Major Change ◽  
Covalent Bonds ◽  
Ordered Structures ◽  
Textural Characteristic ◽  
Physicochemical Changes ◽  
Heating Treatment ◽  
Weight Protein ◽  
Β Sheet

The behaviors of starch and protein in wheat flour during heating were investigated, and the molecular changes of starch and protein and their effects on the textural characteristics were assessed. The results showed that with the increased temperature, soluble protein aggregated to insoluble high-molecular-weight protein polymers when the heating temperature exceeded 70 °C, and the aggregation of protein was mainly caused by covalent bonds of disulfide (SS) bonds. Hydrophobic interaction was the main noncovalent bond that participated in the formation of protein aggregates. The major change in the secondary structure during heating was a pronounced transition towards β-sheet-like structures. Considerable disruption of ordered structures of starch occurred at 70 °C, and starch was fully gelatinized at 80 °C. Typical starch pasting profiles of cooked flour were observed when the temperature was below 70 °C, and heat treatment decreased the pasting viscosity of the cooked flour from control to 80 °C, whereas the viscosity of the wheat flour increased in heating treatment at 90, 95 and 100 °C. The intense protein-starch interaction during heating affected the textural characteristic of flour gelation, which showed higher strength at 90, 95 and 100 °C. This study may provide a basis for improving wheat flour processing conditions and could lead to the production of new wheat products.

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