Physical biology of biomembranes and biomolecules (PHYBIOM)

Haque, Md Mozzammel ORCID: (2020) Physical biology of biomembranes and biomolecules (PHYBIOM). [Doctorate by Public Works]

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To study mechanical properties of red blood cells, the combination of an AC dielectrophoretic apparatus and a single-beam optical tweezers were used. The experiments were performed with high frequency (e.g. 10 MHz) below the second turnover point between positive and negative dielectrophoresis. The electronic response of RBCs is dominated by the local interactions with the trapping beams.

The elastic modulus was determined (μ = 1.80 ± 0.5 μN/m) by measuring the geometrical parameters of RBCs as a function of an applied voltage. However, the deformation of the red cell membrane was determined (Deformed gradient =0.08) from the maximum applied voltage when a spherical RBC escapes to the electrode from the trapping centre. These results were compared with similar experimental values obtained from other techniques. This is easy to use an alternative method to determine the mechanical properties of RBCs.

Solute transport across cell membranes (e.g. RBC membrane) is the ubiquitous phenomenon, whose diffusion rate depends on the narrowest portion of membrane pores and the architecture of diffusing solutes. When a solute is confined in the critical area of membrane pores, which shows a quite different behavior compared to the homogenous bulk fluid whose transport is isotropic in all directions.

The solute size and shape have been determined using the allometric scaling law, which explores the variation in the diffusion coefficient for solutes of different size and structure in physiological environments. Overall rates of diffusion through cell membranes have been determined based on membrane composition, local architecture, and the extend of binding.

The functional group structures of protein folding (e.g. RBCs membrane protein) have been investigated using classical quantum biology based on infrared spectroscopy in polar groups capable of forming hydrogen bonds. The equivalence of infrared radiant energy and the bending energy of oscillating atoms along bonds is reliant on the reduced Planck constant, reduced mass and bond stiffness. The defined quantum biological equation is used to determine the deformation value changes from its equilibrium bond angle, which is estimated from the molecular geometry, in the hydrogen-bonded section of a polypeptide chain. This approach also quantifies substrates fit into the active sites of receptors by modifying the lock
and key model.

Proper protein folding determination is the minimization of free potential energy and adds order to the system. However, the hydrophobic force at protein side chains has been determined by the enthalpic effect of solutes, which may play a crucial role in protein misfolding. The “wrong” solutes are the hydrophobic dominated effect, which is the major driving force for protein misfolding. The interactions between hydrophobic solutes and protein side chains involve the rearrangement of side chains by disrupting protein backbone hydrogen bonds. The hydrophobic interaction is a thermodynamic process, which has been investigated by minimizing the potential energy that changes from enthalpy to thermal energy or vice versa as a temperature. Therefore, the enthalpic temperature due to macromolecular deformation defines the temperature limit for protein misfolding. The deformation temperature limit is the lowest possible temperature achievable with protein misfolding.

Item Type: Doctorate by Public Works
Research Areas: A. > School of Science and Technology > Natural Sciences
B. > Doctorates by Public Works
Item ID: 29908
Depositing User: Brigitte Joerg
Date Deposited: 13 May 2020 19:06
Last Modified: 20 May 2020 03:07

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