A fluorescence spectroscopic study of a coagulating protein extracted from Moringa oleifera seeds

Kwaambwa, Habauka M.; Maikokera, Raymond

doi:10.1016/j.colsurfb.2007.06.015

Cited by 59 publications

(51 citation statements)

References 22 publications

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“…However, only Trp could absorb the longest wavelength than Tyr and Phe. Intrinsic fluorescence parameter like intensity and wavelength maxima (λ max ) provide excellent means for studying structural dynamics and polarity of lipase [31][32][33]. ARM and R157S lipases contain eight Trp residues at positions 19, 30, 40, 60, 234, 255, 313 and 348.…”

Section: Fluorescence Analysismentioning

confidence: 99%

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The Role of Arg157Ser in Improving the Compactness and Stability of ARM Lipase

Salleh¹

2012

JCSB

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Consensus approach is an efficient strategy to identify hot residue important for compactness and stability of protein. Structure of ARM lipase was modeled to explore the possible effect of critical point mutation towards structure and function. The significant difference of amino acid at position 157 between ARM lipase (Arg157) and other thermostable lipases (Ser157) was targeted as a critical residue. Using YASARA software, Arg157 was substituted to Ser and subsequently the energy minimized. Both ARM and R157S lipases were analyzed by MD simulations at different temperatures (50ºC,60ºC, and 70ºC). MD simulation result showed that R157S lipase had lower value of RMSD, RMSF, solvent accessible surface area (SASA) and radius of gyration than native ARM lipase. It indicated that R157S lipase had higher compactness in the structure leading to enhanced stability. To validate the computational data, the substitution of Arg157 to Ser has been conducted using site-directed mutagenesis experimentally. The catalytic efficiency (k cat /K M ) of R157S lipase was refold better than ARM lipase of 70°C. Circular dichorism study revealed that R157S lipase had increased thermostability with higher T m value (71.6°C) than its wildtype (63.9°C) indicating a better compactness as revealed by spectrofluorocence study. Thus the rational design of substituting Arg157 with Ser improved the protein folding of mutant lipase as shown in MD simulations and subsequently increased the catalytic effectiveness and thermodynamic stability. during evolution. The substitution of critical residue was analyzed using in silico to avoid unnecessary conformational distortion in engineered lipase and validate with kinetic study and thermodynamic study. Methods Preparation of 3D structures of ARM and R157S lipasesThe 3D structure of ARM lipase was predicted by comparative modeling. The first step in comparative modeling is the assignment of the unknown ARM lipase structure to a protein family with thousands of sequences already stored in protein databases (PDB). The structure of ARM lipase was modeled using available software packages such as HOMOLOGY and MODELLER, Accelrys, San Diego (http://www. accelrys.com). The unknown ARM lipase structure (target protein) was built from the known 3D structure of T1 lipase (2DSN) as a template. The final model of ARM lipase was evaluated using Ramachandran plot. Using YASARA, the three-dimensional structure of the mutant (R157S lipase) was modeled by substituting Arg157 to Ser and energy minimization was used to release bad contact. MD simulations of ARM and R157S lipasesMD simulations were performed on ARM lipase and R157S lipase structures using Amber03 force field in YASARA package. The periodic box was filled with explicit water molecules to a density of 0.98320 g/l. The whole system was neutralized by adding counter ions and all ionizable protein groups were protonated according to their tabulated pKa values at pH 7 of the medium. Water molecules were relaxed by simulated annealing procedure. Minimiza...

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Section: Fluorescence Analysismentioning

confidence: 99%

“…The increased fluorescence intensity of ARM lipase might probably contribute to the perturbations in the local environment of Trp residues. It indicated that the Trp was shielded from bulk water but not located in the hydrophobic core of the lipases [33]. Amada et al [34] stated that the red-shifting of Pseudomonas sp.…”

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confidence: 99%

The Role of Arg157Ser in Improving the Compactness and Stability of ARM Lipase

Salleh¹

2012

JCSB

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“…In our previous work, we attempted dissolution enhancement and amorphous state stabilization of meloxicam with moringa coagulant (MC) as a polymer and using spray drying as the methodology (6). MC is a heterogeneous, cationic biopolymer of molecular weight 6-12 kDa and isoelectric point between 10 and 11, obtained by aqueous extraction of Moringa seeds belonging to family Moringaceae, which has been used for the purification of water since time immemorial (7,23). Structural and amino acid analysis of MC has revealed a total of 60 residues having high contents of glutamine, arginine, and proline in the sequence; "QGPGRQPDFQRCGQQLRNISPPQRCPSLRQAVQLTH-QQQGQVGPQQVRQMYRVASNIPST" (8).…”

Section: Introductionmentioning

confidence: 99%

Solid-State Characterization and Dissolution Properties of Meloxicam–Moringa Coagulant–PVP Ternary Solid Dispersions

et al. 2013

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Abstract. The effect of ternary solid dispersions of poor water-soluble NSAID meloxicam with moringa coagulant (obtained by salt extraction of moringa seeds) and polyvinylpyrrolidone on the in vitro dissolution properties has been investigated. Binary (meloxicam-moringa and meloxicam-polyvinylpyrrolidone (PVP)) and ternary (meloxicam-moringa-PVP) systems were prepared by physical kneading and ball milling and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffractometry. The in vitro dissolution behavior of meloxicam from the different products was evaluated by means of United States Pharmacopeia type II dissolution apparatus. The results of solid-state studies indicated the presence of strong interactions between meloxicam, moringa, and PVP which were of totally amorphous nature. All ternary combinations were significantly more effective than the corresponding binary systems in improving the dissolution rate of meloxicam. The best performance in this respect was given by the ternary combination employing meloxicam-moringa-PVP ratio of [1:(3:1)] prepared by ball milling, with about six times increase in percent dissolution rate, whereas meloxicam-moringa (1:3) and meloxicam-PVP (1:4) prepared by ball milling improved dissolution of meloxicam by almost 3-and 2.5-folds, respectively. The achieved excellent dissolution enhancement of meloxicam in the ternary systems was attributed to the combined effects of impartation of hydrophilic characteristic by PVP, as well as to the synergistic interaction between moringa and PVP.

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“…Moreover, with the addition of 15% mannitol, sorbitol and xylitol, the fluorescence intensity of SPI decreased from 872 to 757, 712, and 692, respectively. Previous studies indicated that the fluorescence emission maximum shifted to a shorter wavelength and the fluorescence intensity decreased as the environmental hydrophobicity of fluorophore decreased (Kwaambwa & Maikokera 2007;Wu et al 2009). Although the blue shift of the fluorescence emission maximum of SPI added 15% (w/w) polyols is not significant, the simultaneous decrease in fluorescence intensity in our study is an indicative of conformational changes of SPI.…”

Section: Resultsmentioning

confidence: 97%

Effect of cosolvents (polyols) on structural and foaming properties of soy protein isolate

Pan¹,

Meng²,

Jiang³

et al. 2017

Czech J. Food Sci.

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Pan M., Meng X., Jiang L., Yu D., Liu T. (2017): Effect of cosolvents (polyols) on structural and foaming properties of soy protein isolate. Czech J. Food Sci., 35: 57-66.Effect of polyols (mannitol, sorbitol, and xylitol) at three concentrations (5, 10, and 15% w/w) on the structure of soy protein isolates (SPI) was investigated. Changes in foaming properties of SPI were then examined with the addition of polyols at different concentrations. The interactions between SPI and polyols resulted in a substantial decrease in protein surface hydrophobicity and intrinsic tryptophan fluorescence intensity, along with the covering of tyrosine. Furthermore, circular dichroism (CD) spectroscopy of SPI suggested that a more ordered and compact conformation was induced by polyols. Consequently, these structural changes led to lower foamability of SPI. An increase in the viscosity of SPI suspension seemed to be advantageous for improving the foam stability of SPI.

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A fluorescence spectroscopic study of a coagulating protein extracted from Moringa oleifera seeds

Cited by 59 publications

References 22 publications

The Role of Arg157Ser in Improving the Compactness and Stability of ARM Lipase

The Role of Arg157Ser in Improving the Compactness and Stability of ARM Lipase

Solid-State Characterization and Dissolution Properties of Meloxicam–Moringa Coagulant–PVP Ternary Solid Dispersions

Effect of cosolvents (polyols) on structural and foaming properties of soy protein isolate

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