Function Of Protein Molecules Research Articles

A cell-free biosensor for multiplexed and sensitive detection of biological warfare agents

The rapid and precise detection of pathogenic agents is critical for public health and societal stability. The detection of biological warfare agents (BWAs) is especially vital within military and counter-terrorism contexts, essential in defending against biological threats. Traditional methods, such as polymerase chain reaction (PCR), are limited by their need for specific settings, impacting their adaptability and versatility. This study introduces a cell-free biosensor for BWA detection by converting the 16S rRNA of targeted pathogens into detectable functional protein molecules. The modular nature of this approach allows for the flexible configuration of pathogen detection, enabling the simultaneous identification of multiple pathogenic 16S rRNAs through customized reporter proteins for each targeted sequence. Furthermore, we demonstrate how this method integrates with techniques utilizing retroreflective Janus particles (RJPs) for facile and highly sensitive pathogen detection. The cell-free biosensor, employing RJPs to measure the reflection of non-chromatic white light, can detect 16S rRNA from BWAs at femtomolar levels, corresponding to tens of colony-forming units per milliliter of pathogenic bacteria. These findings represent a significant advancement in pathogen detection, offering a more efficient and accessible alternative to conventional methodologies.

Length-Dependent Collective Vibrational Dynamics in Alpha-Helices.

Functions of protein molecules in nature are closely associated with their well-defined three-dimensional structures and dynamics in body fluid. So far, many efforts have been made to reveal the relation of protein structure, dynamics, and function, but the structural origin of protein dynamics, especially for secondary structures as building blocks of conformation transition, is still ambiguous. Here we theoretically uncover the collective vibrations of elastic poly-alanine α-helices and find vibration patterns that are distinctively different over residue numbers ranging from 20 to 80. Contrary to the decreasing vibration magnitude from ends to the middle region for short helices, the vibration magnitude for long helices takes the minimum at approximately 1/5 of helix length from ends but reaches a peak at the center. Further analysis indicates that major vibrational modes of helical structures strongly depend on their lengths, where the twist mode dominates in the vibrations of short helices while the bend mode dominates the long ones analogous to an elastic Euler beam. The helix-coil transition pathway is also affected by the alternation of the first-order mode in helices with different lengths. The dynamic properties of the helical polypeptides are promising to be harnessed for de novo design of protein-based materials and artificial biomolecules in clinical treatments.

Multimodal approaches for the improvement of the cellular folding of a recombinant iron regulatory protein in E. coli

BackgroundDuring the recombinant protein expression, most heterologous proteins expressed in E. coli cell factories are generated as insoluble and inactive aggregates, which prohibit E. coli from being employed as an expression host despite its numerous advantages and ease of use. The yeast mitochondrial aconitase protein, which has a tendency to aggregate when expressed in E. coli cells in the absence of heterologous chaperones GroEL/ES was utilised as a model to investigate how the modulation of physiological stimuli in the host cell can increase protein solubility. The presence of folding modulators such as exogenous molecular chaperones or osmolytes, as well as process variables such as incubation temperature, inducer concentrations, growth media are all important for cellular folding and are investigated in this study. This study also investigated how the cell's stress response system activates and protects the proteins from aggregation.ResultsThe cells exposed to osmolytes plus a pre-induction heat shock showed a substantial increase in recombinant aconitase activity when combined with modulation of process conditions. The concomitant GroEL/ES expression further assists the folding of these soluble aggregates and increases the functional protein molecules in the cytoplasm of the recombinant E. coli cells.ConclusionsThe recombinant E. coli cells enduring physiological stress provide a cytosolic environment for the enhancement in the solubility and activity of the recombinant proteins. GroEL/ES-expressing cells not only aided in the folding of recombinant proteins, but also had an effect on the physiology of the expression host. The improvement in the specific growth rate and aconitase production during chaperone GroEL/ES co-expression is attributed to the reduction in overall cellular stress caused by the expression host's aggregation-prone recombinant protein expression.Graphical

Study of Protein Structures under the Influence of Imidazolium Based Ionic Liquids

Ionic liquids are nowadays extremely popular in the advanced research field of many disciplines including chemistry, chemical engineering, material science, biology and pharmaceuticals. Unique physico-chemical properties of the ionic liquids such as low vapor pressure, stability, large liquid range, broad solubility and easy modification of structures are responsible for its vast application. Imidazolium based ionic liquids are one of the most widely used ionic liquids and theses are extensively studied in the field of protein research. In this mini-review, imidazolium ionic liquid induced effect on the structure and function of protein molecules are discussed.

Influence of protic ionic liquids on hydration of glycine based peptides

The structure of water, especially around the solute is thought to play an important role in many biological and chemical processes. Water-peptide and cosolvent-peptide interactions are crucial in determining the structure and function of protein molecules. In this work, we present the H-bonding analysis for model peptides like glycyl-glycine (gly-gly), glycine-ւ-valine (gly-val), glycyl-ւ-leucine (gly-leu) and triglycine (trigly) and triethylammonium based carboxylate protic ionic liquids (PILs) in aqueous solutions as well as for peptides in ∼0.2 mol·L−1 of aqueous PIL solutions in the spectral range of 7800–5500 cm−1 using Fourier transform near-infrared (FT-NIR) spectroscopy at 298.15 K. The hydration numbers for peptides and PILs were obtained using NIR method of simultaneous estimation of hydration spectrum and hydration number of a solute dissolved in water. The H-bond of water molecules around peptides and PILs are found to be stronger and shorter than those in pure liquid water. We observe that the hydration shell around zwitterions is a clathrate-like cluster of water in which ions entrap. Watery network analysis confirms that singly H-bonded species or NHBs changes to partial or distorted ice-like structures of water in the hydration shell of PILs. The overall water H-bonding in the hydration sphere of PILs increases in the order TEAF < TEAA < TEAG < TEAPy ≈ TEAP < TEAB. The influence of PILs on hydration behavior of peptides is explored in terms of H-bonding, cooperativity, hydrophobicity, water structural changes, ionic interactions etc.

Identification and biological analysis of LncSPRY4-IT1-targeted functional proteins in photoaging skin.

Skin photoaging, main causes of skin aging, is induced by chronic UV irradiation. LncSPRY4-IT1, a broadly expressed lncRNA, takes part in various biological functions by combining with functional protein molecules. However, the role of LncSPRY4-IT1 in skin photoaging process has not been characterized. This study is to investigate the interacting proteins of LncSPRY4-IT1 by combining RNA pull-down, high-throughput, and bioinformatic analysis. Human skin fibroblasts (HDFs) were exposed to 10J/cm2 UVA irradiation, once a day for 14days. LncSPRY4-IT1 expression was qualified via RT-PCR. In vitro RNA pull-down assays and liquid chromatography-mass spectrometry analysis were used to identify the LncSPRY4-IT1-related proteins. Functional annotation analysis and pathway enrichment were preformed via Gene Ontology and KEGG. LncSPRY4-IT1 expression in photoaging fibroblasts was increased 1.66±0.23 folds. 181 LncSPRY4-IT1-interacting proteins in UVA-induced photoaging skin fibroblast irradiation were identified, of which 56 proteins with two or more unique peptides, 73 proteins related to RNA processing, and 5 proteins related to DNA processing. High-throughput and bioinformatic analysis showed that LncSPRY4-IT1-targeting proteins were involved in cellular process, metabolic process, biological regulation, and cell part in skin photoaging process. The KEGG revealed that LncSPRY4-IT1-targeting proteins were mainly enriched in metabolic pathways. The results of our studies illuminate how LncSPRY4-IT1 formed a LncRNA-protein regulatory network in skin photoaging mechanisms and suggest that LncSPRY4-IT1 may serve as a novel upstream intervention target for the prevention and treatment of photoaging and related skin diseases.

Exact and WKB-approximate distributions in a gene expression model with feedback in burst frequency, burst size, and protein stability

&lt;p style='text-indent:20px;'&gt;The expression of individual genes into functional protein molecules is a noisy dynamical process. Here we model the protein concentration as a jump-drift process which combines discrete stochastic production bursts (jumps) with continuous deterministic decay (drift). We allow the drift rate, the jump rate, and the jump size to depend on the protein level to implement feedback in protein stability, burst frequency, and burst size. We specifically focus on positive feedback in burst size, while allowing for arbitrary autoregulation in burst frequency and protein stability. Two versions of feedback in burst size are thereby considered: in the first, newly produced molecules instantly participate in feedback, even within the same burst; in the second, within-burst regulation does not occur due to the so-called infinitesimal delay. Without infinitesimal delay, the model is explicitly solvable; with its inclusion, an exact distribution to the model is unavailable, but we are able to construct a WKB approximation that applies in the asymptotic regime of small but frequent bursts. Comparing the asymptotic behaviour of the two model versions, we report that they yield the same WKB quasi-potential but a different exponential prefactor. We illustrate the difference on the case of a bimodal protein distribution sustained by a sigmoid feedback in burst size: we show that the omission of the infinitesimal delay overestimates the weight of the upper mode of the protein distribution. The analytic results are supported by kinetic Monte-Carlo simulations.&lt;/p&gt;

Application of Functional Biocompatible Nanomaterials to Improve Curcumin Bioavailability.

Curcumin is a lipophilic natural product extracted from turmeric and commonly used as a dietary spice. Being multi-functional, curcumin has been proposed in the prevention and treatment of a broad spectrum of diseases. However, due to unsatisfactory aqueous solubility and hence low bioavailability, clinical application of curcumin has been greatly restrained. To break these limitations, biocompatible nanoformulation, such as liposomes, nanoparticles, micelles, nanoemulsions and conjugates has been employed as alternatives to improve in vivo delivery of curcumin. In this scenario, in order to enhance bioavailability of curcumin, the choice of effective molecules as facilitators is of prominence. In this review, we focus on functional biocompatible materials, including polymers, protein molecules, polysaccharide, surface stabilizers and phospholipid complexes, and decipher their potential applications as how they assist to promote medicinal performance of curcumin.

Soybean Lecithin-Mediated Nanoporous PLGA Microspheres with Highly Entrapped and Controlled Released BMP-2 as a Stem Cell Platform.

Injectable polymer microsphere-based stem cell delivery systems have a severe problem that they do not offer a desirable environment for stem cell adhesion, proliferation, and differentiation because it is difficult to entrap a large number of hydrophilic functional protein molecules into the core of hydrophobic polymer microspheres. In this work, soybean lecithin (SL) is applied to entrap hydrophilic bone morphogenic protein-2 (BMP-2) into nanoporous poly(lactide-co-glycolide) (PLGA)-based microspheres by a two-step method: SL/BMP-2 complexes preparation and PLGA/SL/BMP-2 microsphere preparation. The measurements of their physicochemical properties show that PLGA/SL/BMP-2 microspheres had significantly higher BMP-2 entrapment efficiency and controlled triphasic BMP-2 release behavior compared with PLGA/BMP-2 microspheres. Furthermore, the in vitro and in vivo stem cell behaviors on PLGA/SL/BMP-2 microspheres are analyzed. Compared with PLGA/BMP-2 microspheres, PLGA/SL/BMP-2 microspheres have significantly higher in vitro and in vivo stem cell attachment, proliferation, differentiation, and matrix mineralization abilities. Therefore, injectable nanoporous PLGA/SL/BMP-2 microspheres can be potentially used as a stem cell platform for bone tissue regeneration. In addition, SL can be potentially used to prepare hydrophilic protein-loaded hydrophobic polymer microspheres with highly entrapped and controlled release of proteins.

Mechanical Model of Hydrogen Bonds in Protein Molecules

The unique properties of protein molecules have motivated researchers exploit them in the design and fabrication of bio-mimetic nano devices to perform a special task. Function of protein molecules is in turn dependent on their 3D structure and their ability to modify their shape for a specific task. To study and manipulate protein molecules we need to have knowledge of mechanical properties of these molecules. In this paper a multiscale model to predict stiffness of helical protein molecules has been developed. Hydrogen bonds as major contributing factor to proteins flexibility, are modeled as elastic springs based on their empirical potential energy. Such mechanical representation of hydrogen bonds enables us to obtain the stiffness ellipsoid of hydrogen bonds which leads to an understanding of the directional stiffness of protein molecules. The model has also been applied to three different protein molecules whose stiffness were reported in the literature. The comparison shows an agreement between the stiffness computed by the proposed model and that obtained through experiments and/or Molecular Dynamics (MD) simulations.

Ribonucleic acid (RNA) biosynthesis in human cancer.

In many respects, the most remarkable chemical substances within the genome of eukaryotic cells are remarkable proteins which are the critical structural and functional units of living cells. The specifications for everything that goes in the cell are natural digital-to-digital decoding process in an archive sequence by deoxyribonucleic acid (DNA) and an articulate construction by ribonucleic acid (RNA). The products of DNA transcription are long polymers of ribonucleotides rather than deoxyribonucleotides and are termed ribonucleic acids. Certain deoxyribonucleotide sequences, or genes, give rise to transfer RNA (tRNA) and other ribosomal RNA (rRNA) when transcribed. The ribonucleotide sequences fold extensively and rRNA is associated with specific proteins to yield the essential cell components, ribosomes. Transcription of other special sequences yields messenger RNAs (mRNAs) that contain ribonucleotide sequences that will be ultimately translated into new types of amino acid sequences of functional cellular protein molecules. This switch to a different variety of cellular molecular sequences is complex, but each sequence of the three ribonucleotides specifies the insertion of one particular amino acid into the polypeptide chain under production. Whilst mRNA is considered the vehicle by which genetic information is transmitted from the genome and allocated in the appropriate cytoplasmic sites for translation into protein via cap-dependent mechanism, the actual translation depends also on the presence of other so-called household and luxury protein molecules. Recent evidence suggests RNA species are required at initiation, because treatment of cells with antibiotics or drugs that inhibit RNA synthesis cause a decrease in protein synthesis. The rRNA is necessary as a structural constituent of the ribosomes upon which translation takes place, whereas tRNA is necessary as an adaptor in amino acid activation and elongation protein chains to ribosomes. In this article, we review malignant tumor, with stem like properties, and recent technical advances into the phenomenon of micro-particles and micro-vesicles containing cell-free nucleic acids that circulate plasma. New areas of research have been opened into screening tumor telomerase progression, prognosis of aptamers targeting cell surface, monitoring the efficacy of anticancer therapies, oncogenic transformation of host cell, and RNA polymerases role in the cell cycle progression and differentiation.

Colored petri nets to model gene mutation and amino acids classification

The genetic code is the triplet code based on the three-letter codons, which determines the specific amino acid sequences in proteins synthesis. Choosing an appropriate model for processing these codons is a useful method to study genetic processes in Molecular Biology. As an effective modeling tool of discrete event dynamic systems (DEDS), colored petri net (CPN) has been used for modeling several biological systems, such as metabolic pathways and genetic regulatory networks. According to the genetic code table, CPN is employed to model the process of genetic information transmission. In this paper, we propose a CPN model of amino acids classification, and further present the improved CPN model. Based on the model mentioned above, we give another CPN model to classify the type of gene mutations via contrasting the bases of DNA strands and the codons of amino acids along the polypeptide chain. This model is helpful in determining whether a certain gene mutation will cause the changes of the structures and functions of protein molecules. The effectiveness and accuracy of the presented model are illustrated by the examples in this paper.

Pressure Sensitive Reaction of F1-ATPase

F1-ATPase is a rotational stepping molecular motor in which γ subunit rotates 120o against the α3β3 cylinder upon one ATP molecule hydrolysis. This 120o step is further divided into 80o and 40o substeps and each substep is triggered by ATP binding and ADP release and by ATP hydrolysis and Pi release, respectively. The stepping motion was sensitive against physical and chemical conditions, such as temperature and load Hydrostatic pressure is also a physical parameter to modulate the structure and function of protein molecules. Here, we developed a novel assay that monitored the stepping motion of single F1-ATPase molecules under various pressure conditions [1]. At ambient conditions, F1-ATPases derived from thermophilic Bacillus PS3 smoothly rotated with 9 Hz in the presence of 2 mM ATP. The rotational rate decreased with increased pressure, and then reached to 3 Hz and became stepping rotation by slowing a certain dwell at 140 MPa In order to identify which chemical state this dwell corresponds, the mutant F1(βE190D) which shows the pause of ATP catalytic dwell due to extremely slow ATP hydrolysis even under Vmax condition [2] was used. This pressure dependent dwell became obvious at +40o from catalytic dwell with applying pressure, i.e., it is the same position as ATP binding, where F1 executes ATP binding and ADP release on different catalytic sites. Thus, applied pressures seem to inhibit the ATP binding and/or ADP release reactions.[1] Nishiyama et al., Biophys J. 96(3) 1142-1150 (2009).[2] Shimabukuro et al.,Proc. Natl. Acad. Sci. U.S.A. 100, 14731–14736 (2003).

Atto-Newton X-Ray Radiation Pressure Force on Gold Nanocrystal in Aqueous Solution

In micro-sized force field, radiation pressure forces acting on an object surface have been widely applied as a tool for laser trapping and cooling of the visible light. In the region of short-wavelength, we confirmed the existence of atto-Newton (aN) level's radiation pressure force measured by using Diffracted X-ray Tracking (DXT) which is tracing the X-ray diffraction spots from the gold nanocrystal was labeled on the protein molecule at single molecular level [1].In this study, we succeeded in measuring the modified dynamic rotational Brownian behaviors of the gold nanocrystal in an aqueous solution at micro-sec. levels by varying the wavelength and flux of the incident X-ray probe. As a result, we observed a clear energy-dependent radiation pressure in the X-ray axial direction (2 theta) by comparing with a concentric circle direction (chi: no-pressure direction). And the observed pressures were able to be estimated from the X-ray wavelengths and flux. Furthermore, we found the presence of the resultant forces of X-ray radiation pressure on several diffracted crystal planes from analyzing the angular distributions of accelerated motions. This phenomenon expects to open a new application of X-ray science.For example, we can utilize this X-ray resultant force for the trapping of nano-probe and the crystal growth azimuth control during crystal growths. In addition, we proved that the ultra-fast DXT using protein molecules labeled the gold nanocrystal [2] can detect aN level's force field in functional protein molecules. In the future, we can detect dynamic structural changes of functional surface induced by an ultra-small force field that cannot be detected by STM and AFM.[1] Y. C. Sasaki et al., Appl. Phys. Lett., 89, 053121(2006).[2] H. Shimizu et al., Cell, 132, 67–78 (2008).

Thin films of vitronectin transferred by MAPLE

We report on matrix-assisted pulsed laser evaporation (MAPLE) transfer of intact and functional protein molecules from a cryogenic aliquot obtained by freezing a protein-saline buffer solution. Vitronectin (Vn), an extracellular matrix protein with distinctive active domains for cell attachment and signalization, was expelled from frozen targets by KrF* excimer laser irradiation, and then immobilized on substrates. Particulates surrounded by a dense matrix were observed by optical, profilometry and AFM studies. The composition preservation of MAPLE-deposited protein films versus drop-cast films was demonstrated by FTIR and immunostaining studies. The stability and integrity of Vn after transfer was shown by their interaction with human osteoprogenitor cells in which actin filaments stretched across the entire cell area and clear focal points with surface were formed. The absence of detectable degradation of protein structure after MAPLE immobilization could provide benefits to surface functionalization for biomedical applications.

Application of Colloidal Palladium Nanoparticles for Labeling in Electron Microscopy

The application of palladium nanoparticles as electron-dense markers for labeling in both transmission and scanning electron microscopy requires their conjugation to a specific protein. The conjugation protocol described here includes the dihydrolipoic acid (DHLA) capping of Pd nanoparticles (8 nm equivalent diameter) and their subsequent covalent attachment to functional protein molecules such as streptavidin, protein A, or avidin. The single-step reaction was mediated using the cross-linking agent ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). The final Pd conjugates were fully functional, as demonstrated by labeling of ultrathin resin sections of either bovine serum albumin or secretory granules of the salivary gland isolated from the partially fed female Ixodes ricinus tick. The results of bovine serum labeling were quantified, statistically evaluated, and compared with results obtained using commercially available gold particle conjugates (10 nm diameter). The highest values of labeling density were achieved using both streptavidin-Pd (106 ± 7 particles/μm2) and protein A-Au conjugates (130 ± 18 particles/μm2) compared to a commercial streptavidin-Au (66 ± 16 particles/μm2) and protein A-Pd conjugates (70 ± 11 particles/μm2). The concentrations of both DHLA and EDC, pH during conjugation, and finally thorough washing away of unbound proteins crucially influenced conjugation.

Functionalisation of solid material surface with functional protein molecules for bioelectronic properties

<title/>Molecularly functionalizations of electrodes, including semiconductors, open new function and application. Especially in cases of a molecular electronic materials with molecular-catalyst and electrochemical reaction, functional connection between molecule and electrode is a key part of whole process to provide device function. In the case of such the man-made molecular-catalytic electrochemical reaction systems, there are two interfaces on an electrode; a solution phase-enzyme layer interface and an enzyme layer-electrode interface. These interfaces act as a chemical reaction (including enzymatic reaction) interface and a physicochemical reaction interface respectively. There are late-limits in both interfaces. The interfacial rate limits become conspicuous in cases of macro-molecular interface, as such as enzyme. In order to break down the interfacial rate-limits, the molecular interfaces have to be designed as optimized both physical structure and chemical structure. In the present manuscript describes the fabrication of macro-molecular interfaces on an electrode mainly based on authors resent research.

Physical insights to the bio-energy transport in the protein molecules: Comment on “The theory of bio-energy transport in the protein molecules and its properties” by Pang Xiao-feng

The bio-energy transport in living systems plays an important role in life activities, such as the muscle contraction, DNA duplication and the neuroelectric pulse transfer on membranes of neurocytes as well as calcium and sodium pumps [1–3]. To understand the mechanism of the bio-energy transport in these processes is a fundamental issue for biophysics, which will provide a microscopic insight to the basic physical, chemical and biological processes and functions of protein molecules. The biomedical investigations exhibit that the bio-energies supplied for most protein activities and functions are related to the adenosine phosphate (ATP) hydrolysis, namely an ATP molecule reacts with water environment releasing the energy 0.43 eV under normal physiological conditions [1–3]. Physically, the ATP energy released could change its conformation and configuration by the amide-I vibration. Experimental measurement indicates that only a half of the energy 0.205 eV in the ATP hydrolysis can be observed by the amide-I vibration [3], which implies that the energy released by ATP hydrolysis could couple other degrees of freedom, and could be related to some quantum effects. The challenging problems are what mechanism of state changes of ATP molecule in the ATP hydrolysis and how to understand various biological self-organization processes by the bio-energy transport, such as self-assembling, and self-renovating, which could be related to fundamental physical concepts: coherence, order, collective effects and correlations [3]. A lot of theoretical effort focus on the bio-energy transport in the α-helix structure of protein, including Davydov’s [1,2], Takeno’s [5], Yomosa’s [6], and Pang’s models [2–4]. The key physics involves the non-linear interaction between phonon and deformation of the protein molecules, the soliton migration, and the exciton–soliton interaction. Actually, there is no unified theory to understand all phenomena of the bio-energy transport in the protein molecules due to the complicated life processes. There are still many arguments and puzzles on the bio-energy transport, such as the soliton stability in room temperature, the charge transfer, the quantum and thermal fluctuations. Pang Xiao-feng in his review article gave a brief review of the theoretical studies of the bio-energy transport in protein molecules. He described the basic problems of the bio-energy transport in protein molecules and assessed the main results and unsolved problems of various different models. Particularly, he presented his main contributions in this issue. The key point of the Pang’s model is that he considers the effects of the correlation, collective excitation and collective motions of the protein molecule such that his results agree with experimental results. He obtained

Bioinformatics-led design of single-chain antibody molecules targeting DNA sequences for retinoblastoma.

To analyze the relationship between the structure and function of single-chain Fv antibody (scFv) with bioinformatics methods, so as to provide theoretical basis for retinoblastoma targeted therapy. Single-chain antibodies are reconstructed for cancer-targeted therapy to provide good penetration into tumor tissue and to improve their pharmacokinetics in vivo, offering a clinically valuable application. The relationship needs to be analyzed that there may be some variations between the structure and function of the fusion proteins, and the relationship between the structure and function of protein molecules was obtained through analyzing relevant literature at home and abroad as well as modeling analysis. Through our analysis of the interaction region between the antibody and the antigen, and of the binding sites for molecular conformation, it is clear that existing antibodies need to be modified at the DNA sequence level, enhancing the biological activity of the antibodies. Based on the view that bio-molecular computer models are closely integrated with biological experiments, a bio-molecular structure-activity relationship model can be established in terms of molecular conformation, physical and chemical properties and the biological activity of single-chain antibodies. Two enlightenments are obtained from our analysis. On the one hand, the structure-activity relationship is clear for new immune molecules at the gene expression level. On the other hand, a single-chain antibody molecule can be designed and optimized for the cancer-oriented treatment. In this article, we provide the theoretical and experimental basis for the development of single-chain antibodies appropriate for retinoblastoma therapy.

Observations of X-Ray Radiation Pressure Force Using High-Speed Diffracted X-Ray Tracking

In single molecular science and technology, it is very important to control dynamical Brownian motions of individual functional protein molecules. Optical trap and tweezer using visible light is the first demonstration of controlling micron-sized particles or molecules. In order to improve both monitoring and controlling internal molecular motions from single molecular units with more super-precisions under in vitro or in vivo physiological conditions, we have proposed new single molecular techniques using shorten wavelength, for example, X-rays, electrons, and neutron. Recently, we observed directed Brownian motions of individual single gold nanocrystals using high-speed Diffracted X-ray Tracking (DXT). We confirmed that this motion is dependent upon X-ray Intensity and the sized of observed gold nanocrystal. The observed force is estimated at atto-Newton level. In my previous research, we utilized the adsorbed protein molecules, and the gold nanocrystals are linked to the adsorbed ones. Because we can not observe free Brownian motions of the individual gold nanocrystals in aqueous solutions using normal speed DXT. In this new experiment of high-speed DXT, a diffraction spot in high-speed DXT was monitored with an X-ray image intensifier (Hamamatsu Photonics, V5445P) and a CMOS CCD camera (FASTCAM SA1.1, Photron) with 128 x 112 pixels. Additionally we utilized high-speed X-ray shutters. The averaged exposure time in single shot was 5μsec.-20μsec. In these experiments, we controlled the size of gold nanocrystals and the energy of quasi-white x-rays. In the future, we will be able to control and measure dynamics of micro- or nano-crystalline materials or labeled single molecular units using x-ray radiation pressure force.