Proteins optical tweezers

In SMD an external force is applied in an attempt to accelerate a chemical process such as unfolding of a protein or dissociation of two molecules. In that respect, it is similar to AFM or optical-tweezers experiments. The applied force is given by ... 

Figure 7. Mechanical unfolding of RNA molecules (a, b) and proteins (c, d) using optical tweezers, (a) Experimental setup in RNA pulling experiments, (b) Pulling cycles in the homologous hairpin and force rip distributions during the unfolding and refolding at three pulling speeds. (C) Equivalent setup in proteins, (d) Force extension curve when pulUng the protein RNAseH. Panel (b) is from Ref. 86. Panels (a) and (d) are a courtesy from C. Cecconi [84]. (See color insert.)...

Same laser for Raman and one optical tweezers 633 nm Neoplastic and normal hematopoietic cells DNA (backbone below 800 cm nucleic acids), protein (phenylalanine, 1,002 cm amide I, 1,650 cm, and amide II 1,570 cm ), lipids, CH2 wagging, 1,200-1,400 cm Detection of cancer infected cells, p < <0.05 sensitivity 98.3% for cancer detection and 97.2% of the cells are correctly analyzed... 

Same laser for Raman and one optical tweezers 633 nm Leukemia cells, T and B lymphocytes DNA, RNA, protein, and lipid vibrations at 785, 1,230, 1,305, and 1,660 cm Detection of cancer infected cells, 95% of normal cells and 90% of cancerous cells were correctly identified... 

Either a double microscope configuration with 1,064 nm for optical trapping and 514.5 nm or same laser for Raman and one optical tweezers 514.5 nm Urological cells, prostate cancer, and bladder cells lines Nucleic acids, lipids, carbohydrates, proteins Fixation protocol and classification of urological cells are investigated. For SurePath fixed cells, sensitivity >72% and specificity 90% For formaline fixed cells sensitivity >93%, specificity 98%... 

Same laser for Raman and one optical tweezers 810 nm Yeast, E. coli and Enterobacter aerogenes Changes of phenylalanine at 1,004 cm Raman spectra of native and heat denaturated cells show that conformational studies of proteins within cells can be studied by Raman tweezers... 

Same laser for Raman and one optical tweezers 780 nm Schizosaccharomyces pombe yeast cell Decrease of intensity in amide I (1,656 cm ) and amide III (1,270 cm ) bands and alterations in tyrosine band at 850 cm Alterations in hydration state of protein could be observed over time... 

Same laser for Raman and one optical tweezers 730 nm Synaptosomes CH2 deformation at 1,445 cm Amide I at 1,657 cm Synaptosomes isolated from rat brain neurons dispersed in buffer solution. Appearing beads reveal that synaptosomes include liposomes and proteins... 

The threshold of the pulse energy to induce the laser tsunami is relatively low for a femtosecond laser compared with nanosecond and picosecond lasers. The laser tsunami expands to a volume of (sub pm)3 around the focal point, when an intense laser pulse is focused into an aqueous solution by a high numerical aperture objective lens. When a culture medium containing living animal cells is irradiated, they could be manipulated by laser tsunami. Mouse NIH 3T3 cells cultured on a substrate can be detached and patterned arbitrarily on substrates [36]. We have also demonstrated that the laser tsunami is strong enough to transfer objects with size of a few 100 pm [37], which is impossible by conventional optical tweezers because the force due to the optical pressure is too weak. In addition we demonstrated for the first time the crystallization of organic molecules and proteins in their super-saturated solution by laser tsunami [38-40]. 

Optical tweezers have since been used to stretch and even unwind DNA unfold the tertiary structure of proteins pull on DNA processing enzymes like RNA polymerase as it walks along DNA resist the force produced by viral capsid packaging motors and manipulate entire mammalian cells, sperms and sub-cellular organelles and vesicles. The applications are manifold and the future possibilities are great. 

In order to study the influence of bacterial osmolytes on the compliance of the protein we described the force as a function of the extensimi by a conventional WLC model. This model has provided reasonable results in many studies where the Scanning Force Microscopy (SFM) or optical tweezers have been used to stretch long proteins, even though it fails in some important situations (as discussed in... 

Optical tweezers 0.1-150 >10ms Actin, DNA, RNA, proteins, molecular motors... 

Optical tweezers have proved useful for the study of lateral heterogeneity and order in cell structure and protein motion. For example, Bustamante, et al. (88) studied the single molecule mechanics of DNA uncoiling. The use of optical tweezers has proved especially useful for the study of lateral heterogeneity and order of lipid layers (89), and a host of problems relating to protein motions see Section 14.11.4. 

---