This paper describes a new and simple method to determine the molecular weight of proteins in dilute solution, with an error smaller than ∼10%, by using the experimental data of a single small-angle X-ray scattering (SAXS) curve measured on a relative scale. This procedure does not require the measurement of SAXS intensity on an absolute scale and does not involve a comparison with another SAXS curve determined from a known standard protein. The proposed procedure can be applied to monodisperse systems of proteins in dilute solution, either in monomeric or multimeric state, and it has been successfully tested on SAXS data experimentally determined for proteins with known molecular weights.
We study here the processes that can be understood as a random walk along a straight line, but with transition rate that depend on the position where the walker is.
Xanthomonas campestris expansin-like X domain is a structurally disordered beta-sheet macromolecule capable of synergistically enhancing enzymatic efficiency of cellulose hydrolysis
An alkaline active feruloyl-CoA synthetase from soil metagenome as a potential key enzyme for lignin valorization strategies
Two versions of the threshold contact process–ordinary and conservative–are studied on a square lattice. In the first, particles are created on active sites, those having at least two nearest neighbor sites occupied, and are annihilated spontaneously.
65 nm and a D(max) of oito.5 nm. To further study the rPTPetaCD conformation in solution, we built rPTPetaCD homology models using as scaffolds the crystallographic structures of RPTPalpha-D1 and RPTPmicro-D1 dimers. These models were, then, superimposed onto ab initio low-resolution SAXS structures. The structural comparisons and sequence alignment analysis of the putative dimerization interfaces provide support to the notion that the rPTPetaCD dimer architecture is more closely related to the crystal structure of autoinhibitory RPTPalpha-D1 dimer than to the dimeric arrangement exemplified by RPTPmicro-D1. Finally, the characterization of rPTPetaCD by fluorescence anisotropy measurements demonstrates that the dimer dissociation is concentration dependent with a dissociation constant of 21.6 +/- 2.0 microM.
When two bodies are placed in thermal contact, the hotter body gives off heat to the colder body. As long as the temperatures are different, there will be a flow of heat between them.
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In this chapter we study mixtures of two components, called binary mixtures which are quite common here in nature, both the homogeneous and heterogeneous.
A system in thermodynamic equilibrium must be stable. This means to say that small perturbations do not remove the system from its equilibrium.
The HPAEC-PAD analysis of the hydrolytic products demonstrated that the end product of the enzymatic hydrolysis is primarily cellobiose, and also small amounts of glucose, cellotriose, and cellotetraose are produced. SAXS data analysis revealed that the enzyme adopts a monomeric state in solution and has a molecular mass of 65.oito kDa as estimated from SAXS data. The daniel dantas mercado livre BlCel9 has an elongated shape composed of an N-terminal family 3 carbohydrate-binding module (CBM3c) and a C-terminal GH9 catalytic domain joined together by 20 amino acid residue long linker peptides. The domains are closely juxtaposed in an extended conformation and form a relatively rigid structure in solution, indicating that the interactions between the CBM3c and GH9 catalytic domains might play a key role in cooperative cellulose biomass recognition and hydrolysis.
Metagenomics has been widely employed for discovery of new enzymes and pathways to conversion of lignocellulosic biomass here to fuels and chemicals. In this context, the present study reports the isolation, recombinant expression, biochemical and structural characterization of a novel endoxylanase family GH10 (SCXyl) identified from sugarcane soil metagenome. The recombinant SCXyl was highly active against xylan from beechwood and showed optimal enzyme activity at pH seis,0 and 45°C. The crystal structure was solved at 2.75 Å resolution, revealing the classical (β/α)oito-barrel fold with a conserved active-sitio pocket and an inherent flexibility of the Trp281-Arg291 loop that can adopt distinct conformational states depending on substrate binding. The capillary electrophoresis analysis of degradation products evidenced that the enzyme displays unusual capacity to degrade small xylooligosaccharides, such as xylotriose, which is consistent to the hydrophobic contacts at the +1 website subsite and low-binding energies of subsites that are distant from the site of hydrolysis.
The protein was purified using a combination of ion exchange and size exclusion chromatography rendering about 30 mg pure protein/l culture medium. Circular dichroism spectroscopy and small-angle X-ray scattering studies of XcEXLX1 reveal that it is a strongly disordered β-sheet protein. Its low resolution envelope fits nicely the crystallographic structure of the homologous protein EXLX1 from Bacillus subtillis.
The mixtures of pure substances are quite common in nature. Some mixtures are homogeneous others are heterogeneous. The atmospheric air is a homogeneous gaseous mixture of nitrogen, oxygen and other gases in smaller proportions.