Protein Crystal Processing Using a Deep-UV Laser

Abstract

We study the level spacing distribution p(s) in the spectrum of random networks. According to our numerical results, the shape of p(s) in the Erdős-Rényi (E-R) random graph is determined by the average degree k and p(s) undergoes a dramatic change when k is varied around the critical point of the percolation transition, k = 1. When k 1, the p(s) is described by the statistics of the Gaussian orthogonal ensemble (GOE), one of the major statistical ensembles in Random Matrix Theory, whereas at k = 1 it follows the Poisson level spacing distribution. Closely above the critical point, p(s) can be described in terms of an intermediate distribution between Poisson and the GOE, the Brodydistribution. Furthermore, below the critical point p(s) can be given with the help of the regularized Gamma-function. Motivated by these results, we analyse the behaviour of p(s) in real networks such as the internet, a word association network and a protein-protein interaction network as well. When the giant component of these networks is destroyed in a node deletion process simulating the networks subjected to intentional attack, their level spacing distribution undergoes a similar transition to that of the E-R graph.

Fully 3D: shaping future synchrotron beamline strategies

“…We have developed novel techniques of protein crystal processing by femtosecond laser [1,2] and pulsed deep-UV laser [3][4][5]. The techniques, named as fs-CACO (femtosecond-laser-induced cut and cleave operation) and PULSA (pulsed UV laser soft ablation), are effective for processing and manipulation of protein crystals without significant damage.…”

Femtosecond laser processing of protein crystals grown in agarose gel

“…To overcome these difficulties, we have previously utilized Deep UV solid and femtosecond lasers to process protein crystals. The risk of denaturation caused by heating can be suppressed by using these lasers with short pulse duration and high beam quality, which enable the processing of a variety of protein crystals [5][6][7][8][9][10][11]. However, these technologies have not yet been established for general use because they still have certain disadvantages to overcome.…”

Femtosecond laser-induced cleaving of protein crystal in water solution

“…We have previously demonstrated that, when a femtosecond laser beam is tightly focused onto a transparent protein crystal in a transparent supersaturated solution in a sealed growth vessel, the crystal can be etched by multiphoton absorption [5]. We have also attempted processing protein crystals using a pulsed deep-UV laser [6,7] but found it difficult to perform processing in sealed growth vessels because the wavelength of the deep-UV laser brings about strong one-photon absorption in the crystal and in the supersaturated solution. Therefore, we consider that crystal processing by a femtosecond laser might be a suitable tool to conduct a series of systematic XRD measurements.…”