[en] A new crystal-mounting method has been developed that involves a combination of controlled humid air and polymer glue for crystal coating. This method is particularly useful when applied to fragile protein crystals that are known to be sensitive to subtle changes in their physicochemical environment. Protein crystals are fragile, and it is sometimes difficult to find conditions suitable for handling and cryocooling the crystals before conducting X-ray diffraction experiments. To overcome this issue, a protein crystal-mounting method has been developed that involves a water-soluble polymer and controlled humid air that can adjust the moisture content of a mounted crystal. By coating crystals with polymer glue and exposing them to controlled humid air, the crystals were stable at room temperature and were cryocooled under optimized humidity. Moreover, the glue-coated crystals reproducibly showed gradual transformations of their lattice constants in response to a change in humidity; thus, using this method, a series of isomorphous crystals can be prepared. This technique is valuable when working on fragile protein crystals, including membrane proteins, and will also be useful for multi-crystal data collection

[en] Recently interest of the aging effects has been increased in Japanese society but it is still not known much about what happens on the aged hairs. The hair-density measurement revealed that the density of human hair decreases with age, which caused by the follow-out of proteins and peptides from the hairs. According to the results of hair investigation between 20 and 50 years women, effluences of protein and peptide become increasing with the age and the degree of the cosmetic treatment. Further studies based on the X-ray CT show that quantity of voids in hair increases with age, which is thought at the origin of the density decrease. (author)

[en] Non-negative matrix factorization (NMF) has been frequently used in research on live cells, biomolecules, and tissues (bio-Raman research) to disentangle the complicated and large sized data. A stagnation is that NMF does not provide unique decomposition, depending on initial settings; that is, NMF returns non-negative spectral components close to the truths, but solely giving several possibilities. In this research, we visualized possible ranges of NMF in binary component system. The mechanism of NMF became more clarified and opened new viewpoints. (author)

[en] During the past two decades, amino acids and amino-acid derivatives have been applied in various fields of protein chemistry. The potential use of amino acids and their derivatives as new precipitating agents is described. Several amino acids and their derivatives are prominent additives in the field of protein chemistry. This study reports the use of charged amino acids and glycine ethyl ester as precipitants in protein crystallization, using hen egg-white lysozyme (HEWL) as a model. A discussion of the crystallization of HEWL using these reagents as precipitating agents is given

[en] The effect of the addition of amino acids and amino acid derivatives on the crystallization of hemoglobin and ribonuclease A has been evaluated. The results showed that certain types of additives expand the concentration conditions in which crystals are formed. Determination of the appropriate conditions for protein crystallization remains a highly empirical process. Preventing protein aggregation is necessary for the formation of single crystals under aggregation-prone solution conditions. Because many amino acids and amino acid derivatives offer a unique combination of solubility and stabilizing properties, they open new avenues into the field of protein aggregation research. The use of amino acids and amino acid derivatives can potentially influence processes such as heat treatment and refolding reactions. The effect of the addition of several amino acids, such as lysine, and several amino acid derivatives, such as glycine ethyl ester and glycine amide, on the crystallization of equine hemoglobin and bovine pancreatic ribonuclease A has been examined. The addition of these amino acids and amino acid derivatives expanded the range of precipitant concentration in which crystals formed without aggregation. The addition of such additives appears to promote the crystallization of proteins

[en] Human prouroguanylin, a precursor protein of a peptide hormone, was expressed in E. coli, refolded, purified and crystallized. The crystals belong to space group P6₁22 and diffract X-rays to 2.5 Å resolution. Uroguanylin, which serves as an endogenous ligand of guanylyl cyclase C, is initially secreted in the form of a precursor, prouroguanylin. The N-terminal region of prouroguanylin interacts with the mature portion of prouroguanylin during the folding pathway. Here, a preliminary X-ray crystallographic study of prouroguanylin is presented. Prouroguanylin was refolded, purified and crystallized using the hanging-drop vapour-diffusion method. Prouroguanylin crystals were cryocooled and used for data collection. The diffraction data showed that the crystals belonged to space group P6₁22, with unit-cell parameters a = b = 55.6, c = 157.7 Å, and diffracted to 2.5 Å resolution. The structure is currently being analyzed

[en] Protein disulfide isomerase (PDI) is known to bind to the thyroid hormone triiodothyronine (T3). Here, the expression, crystallization and preliminary X-ray studies of the b and b′ domains of rat PDI in ligand-free and T3-complexed states are reported. Protein disulfide isomerase (PDI) is a multifunctional protein that catalyzes the formation of a disulfide bond in nascent and misfolded proteins and is also known to bind to the thyroid hormone triiodothyronine (T3). When T3 is bound to PDI its catalytic activity is inhibited, but the biological function of this binding is not well understood. In previous studies, it was found that T3 binds to the bb′ fragment of PDI. Therefore, to clarify the structure of the complex consisting of PDI bound to T3, a crystallographic analysis of the three-dimensional structure of the T3–rat PDI bb′ complex was performed. Native bb′ crystals and T3–bb′ complex crystals were both obtained using the hanging-drop vapour-diffusion technique with 1.6 M trisodium citrate pH 6.2 as a precipitant. The space group of the native bb′ crystals was found to be C222, with unit-cell parameters a = 94.8, b = 114.9, c = 182.9 Å, while the space group of the T3–bb′ complex crystals was P2₁2₁2₁, with unit-cell parameters a = 99.9, b = 184.5, c = 232.2 Å. Diffraction data for the native and complex crystals were collected to resolutions of 3.06 and 3.00 Å, respectively

[en] New types of aggregation suppressors, such as amino acids and their derivatives, were focused on as fourth-component additives. Data were obtained that indicated that the additives promote protein crystallization. Optimal conditions for protein crystallization are difficult to determine because proteins tend to aggregate in saturated solutions. This study comprehensively evaluates amino acids and amino-acid derivatives as additives for crystallization. This fourth component of the solution increases the probability of crystallization of hen egg-white lysozyme in various precipitants owing to a decrease in aggregation. These results suggest that the addition of certain types of amino acids and amino-acid derivatives, such as Arg, Lys and esterified and amidated amino acids, is a simple method of improving the success rate of protein crystallization