Crystallization and preliminary X-ray diffraction analysis of the N-terminal domain of Paenibacillus barcinonensis xylanase 10C containing the CBM22-1-CBM22-2 tandem

© 2015 International Union of Crystallography. A construct containing the CBM22-1-CBM22-2 tandem forming the N-terminal domain of Paenibacillus barcinonensis xylanase 10C (Xyn10C) has been purified and crystallized. A xylan-binding function and an affinity for mixed β-1,3/β-1,4 glucans have previously been demonstrated for some members of the CBM22 family. The sequence of the tandem is homologous to the N-terminal domains found in several thermophilic enzymes. Crystals of this tandem were grown by the streak-seeding method after a long optimization strategy. The structure has been determined by molecular replacement to a resolution of 2.43Å and refinement is under way. This study represents the first structure containing two contiguous CBM22 modules, which will contribute to a better understanding of the role that this multiplicity plays in fine-tuning substrate affinity.Peer Reviewe

Lattice-Energy Calculations on Organometallic Compounds

Lattice-energy calculations in the atom-atom approach have been performed for five organometallic com­ pounds of previously determined crystal structure. Minimization of energy in terms of positional, orienta­ tional, torsional and cell parameters gave satisfactory results. Computation of energy as a function of torsion angle gave two-dimensional cross sections which o108-7681/88/030259-04$03.00 present minimum-energy conformations at maximum deviations of 10° from the experimental conforma­ tions

The crystal structure of Canavalia brasiliensis lectin suggests a correlation between its quaternary conformation and its distinct biological properties from Concanavalin A

AbstractCanavalia brasiliensis lectin was isolated from the seeds of a Brazilian autochthonous Leguminosae plant. Despite extensive amino acid sequence similarity with Concanavalin A, C. brasiliensis lectin exerts in vitro and in vivo cellular effects that are markedly different from those displayed by Concanavalin A. We have solved the crystal structure of the C. brasiliensis lectin at 3.0 Å resolution. The three-dimensional structure of the lectin monomer can be superimposed onto that of Concanavalin A with a root-mean-square deviation for all Cα atoms of 0.65 Å. However, this parameter is 0.84 and 1.62 Å when the C. brasiliensis lectin dimer and tetramer, respectively, are compared with the same structures of Concanavalin A. We suggest that these differences in quaternary structure may account for the different biological properties of these two highly related Leguminosae lectins.© 1997 Federation of European Biochemical Societies

Crystallization and preliminary X-ray diffraction analysis of the N-terminal domain of Paenibacillus barcinonensis xylanase 10C containing the CBM22-1-CBM22-2 tandem

A construct containing the CBM22-1-CBM22-2 tandem forming the N-terminal domain of Paenibacillus barcinonensis xylanase 10C (Xyn10C) has been purified and crystallized. A xylan-binding function and an affinity for mixed [beta]-1,3/[beta]-1,4 glucans have previously been demonstrated for some members of the CBM22 family. The sequence of the tandem is homologous to the N-terminal domains found in several thermophilic enzymes. Crystals of this tandem were grown by the streak-seeding method after a long optimization strategy. The structure has been determined by molecular replacement to a resolution of 2.43 Å and refinement is under way. This study represents the first structure containing two contiguous CBM22 modules, which will contribute to a better understanding of the role that this multiplicity plays in fine-tuning substrate affinit

Crystallization and preliminary X-ray diffraction analysis of Xyn30D from Paenibacillus barcinonensis

Xyn30D, a new member of a recently identified group of xylanases, has been purified and crystallized. Xyn30D is a bimodular enzyme composed of an N-terminal catalytic domain belonging to glycoside hydrolase family 30 (GH30) and a C-terminal family 35 carbohydrate-binding domain (CBM35) able to bind xylans and glucuronic acid. Xyn30D shares the characteristic endo mode of action described for GH30 xylanases, with the hydrolysis of the [beta]-(1,4) bonds of xylan being directed by [alpha]-1,2-linked glucuronate moieties, which have to be placed at the -2 subsite of the xylanase active site. Crystals of the complete enzyme were obtained and a full data set to 2.3 Å resolution was collected using a synchrotron X-ray source. This represents the first bimodular enzyme with the domain architecture GH30-CBM35. This study will contribute to the understanding of the role that the different xylanases play in the depolymerization of glucuronoxylan

Inositol 1,3,4,5,6-pentakisphosphate 2-kinase is a distant IPK member with a singular inositide binding site for axial 2-OH recognition

Inositol phosphates (InsPs) are signaling molecules with multiple roles in cells. In particular Graphic (InsP6) is involved in mRNA export and editing or chromatin remodeling among other events. InsP6 accumulates as mixed salts (phytate) in storage tissues of plants and plays a key role in their physiology. Human diets that are exclusively grain-based provide an excess of InsP6 that, through chelation of metal ions, may have a detrimental effect on human health. Ins(1,3,4,5,6)P5 2-kinase (InsP5 2-kinase or Ipk1) catalyses the synthesis of InsP6 from InsP5 and ATP, and is the only enzyme that transfers a phosphate group to the axial 2-OH of the myo-inositide. We present the first structure for an InsP5 2-kinase in complex with both substrates and products. This enzyme presents a singular structural region for inositide binding that encompasses almost half of the protein. The key residues in substrate binding are identified, with Asp368 being responsible for recognition of the axial 2-OH. This study sheds light on the unique molecular mechanism for the synthesis of the precursor of inositol pyrophosphates

Molecular characterization and heterologous expression of a Xanthophyllomyces dendrorhous ¿-glucosidase with potential for prebiotics production

Abstract Basidiomycetous yeast Xanthophyllomyces dendrorhous expresses an α-glucosidase with strong transglycosylation activity producing prebiotic sugars such as panose and an unusual tetrasaccharides mixture including α–(1–6) bonds as major products, which makes it of biotechnological interest. Initial analysis pointed to a homodimeric protein of 60 kDa subunit as responsible for this activity. In this study, the gene Xd-AlphaGlu was characterized. The 4131-bp-long gene is interrupted by 13 short introns and encodes a protein of 990 amino acids (Xd-AlphaGlu). The N-terminal sequence of the previously detected 60 kDa protein resides in this larger protein at residues 583–602. Functionality of the gene was proved in Saccharomyces cerevisiae, which produced a protein of about 130 kDa containing Xd-AlphaGlu sequences. All properties of the heterologously expressed protein, including thermal and pH profiles, activity on different substrates, and ability to produce prebiotic sugars were similar to that of the α-glucosidase produced in X. dendrorhous. No activity was detected in S. cerevisiae containing exclusively the 1256-bp from gene Xd-AlphaGlu that would encode synthesis of the 60 kDa protein previously detected. Data were compatible with an active monomeric α-glucosidase of 990 amino acids and an inactive hydrolysis product of 60 kDa. Protein Xd-AlphaGlu contained most of the elements characteristic of α-glucosidases included in the glycoside hydrolases family GH31 and its structural model based on the homologous human maltase-lucoamylase was obtained. Remarkably, the Xd-AlphaGlu C-terminal domain presents an unusually long 115-residue insertion that could be involved in this enzyme’s activity against long-size substrates such as maltoheptaose and soluble starch.Spanish Ministry of Economy and Competitiveness supported this research. We thank Fundación Ramón Areces for the institutional grant to the Centro de Biología Molecular Severo OchoaPeer Reviewe

Ultrasonic Array for Obstacle Detection Based on CDMA with Kasami Codes

This paper raises the design of an ultrasonic array for obstacle detection based on Phased Array (PA) techniques, which steers the acoustic beam through the environment by electronics rather than mechanical means. The transmission of every element in the array has been encoded, according to Code Division for Multiple Access (CDMA), which allows multiple beams to be transmitted simultaneously. All these features together enable a parallel scanning system which does not only improve the image rate but also achieves longer inspection distances in comparison with conventional PA techniques

Los minerales de colección como recurso económico en países en vías de desarrollo

El coleccionismo de minerales es una actividad en expansión. El alto nivel de demanda de minerales y de sus derivados posibilita la creación de microempresas en países en vías de desarrollo que, con muy poca inversión de capital, pueden facilitar el desarrollo de áreas rurales sin producir apenas impacto en el medio natural. Un aspecto muy importante para la supervivencia de estas microempresas es que el material tenga la calidad adecuada para su óptima comercialización, cosa que no ocurre en la actualidad con la mayor parte del material que procede de los países en vías de desarrollo. En este trabajo se proporcionan, de forma ilustrada, los criterios que se deben usar para identificar el tipo de material que puede ser interesante para ser comercializado, así como los mecanismos de tratamiento de los minerales desde su lugar de extracción hasta el punto de venta. Mineral collecting is a growing activity. The high demand for minerals and their derivatives has resulted in the creation of micro- companies around the mineral trade in developing countries. This activity could facilitate the development of rural areas with no need of a large capital investment and with minimal environmental impact. The high quality of their products is the most important aspect for the survival of these micro-companies, but nowadays the material that comes from developing countries does not always arrive in the best condition. In this essay the basic criteria are provided for identifying the kind of minerals that are interesting enough to be commercialized, and also the procedures recommended for commercializing them from the place where they are extracted to their point of sale