Browsing by Author "Murakami, Satoshi"

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Laser ablation for protein crystal nucleation and seeding
(2014)
Yoshikawa, Hiroshi Y.
;
Murai, Ryota
;
Adachi, Hiroaki
;
Sugiyama, Shigeru
;
Maruyama, Mihoko
With the recent development in pulsed lasers with ultrashort pulse widths or wavelengths, spatially precise, low- damage processing by femtosecond or deep- UV laser ablation has shown promise for the production of protein single crystals suitable for X- ray crystallography. Femtosecond laser processing of supersaturated solutions can shorten the protein nucleation period or can induce nucleation at low supersaturation, which improves the crystal quality of various proteins including membrane proteins and supra- complexes. In addition to nucleation, processing of protein crystals by femtosecond or deep- UV laser ablation can produce single crystalline micro- or macro- seeds without deterioration of crystal quality. This tutorial review gives an overview of the successful application of laser ablation techniques to nucleation and seeding for the production of protein single crystals, and also describes the advantages from a physico-chemical perspective.
Spatially Precise, Soft Microseeding of Single Protein Crystals by Femtosecond Laser Ablation
(2012-09-01)
Yoshikawa, Hiroshi Y.
;
Hosokawa, Yoichiroh
;
Murai, Ryota
;
Sazaki, Gen
;
Kitatani, Tomoya
We developed a spatially precise, soft microseeding method for the production of single protein crystals that are suitable for X-ray crystallographic studies. We used focused femtosecond laser pulses to produce, via multiphoton absorption processes, seed crystals from small regions (similar to 1 mu m(2)) of crystals. Hen egg-white lysozyme seed crystals, produced in this manner, grew to be single crystals without any deterioration in their crystallinity. We also validated the technique using polycrystals for the membrane protein, acriflavine resistance protein B, for which single crystals are very difficult to obtain. In addition, we found that the shape of a tetragonal lysozyme crystal prepared from the seed could be controlled by altering the time interval between the initiation of crystallization and laser ablation. We also tried to comprehend the mechanism of femtosecond laser-induced microseeding. We visualized the ablated surfaces of the lysozyme crystals by atomic force microscopy and by laser confocal microscopy combined with differential interference microscopy. The results obtained in this study clearly demonstrate that femtosecond laser ablation of protein crystals is based on a photomechanical process, which ejects crystal fragments with little thermal damage. Femtosecond laser ablation is indeed very promising to produce high quality protein seed crystals from polycrystals or cracked crystals that are not suitable for X-ray diffraction studies.