The backbone structure of the thermophilic Thermoanaerobacter tengcongensis ribose binding protein is essentially identical to its mesophilic E. coli homolog

<p>Abstract</p> <p>Background</p> <p>Comparison of experimentally determined mesophilic and thermophilic homologous protein structures is an important tool for understanding the mechanisms that contribute to thermal stability. Of particular interest are pairs of homologous structures that are structurally very similar, but differ significantly in thermal stability.</p> <p>Results</p> <p>We report the X-ray crystal structure of a <it>Thermoanaerobacter tengcongensis </it>ribose binding protein (tteRBP) determined to 1.9 Å resolution. We find that tteRBP is significantly more stable (^<it>app</it><it>T</it>_{<it>m </it>}value ~102°C) than the mesophilic <it>Escherichia coli </it>ribose binding protein (ecRBP) (^<it>app</it><it>T</it>_{<it>m </it>}value ~56°C). The tteRBP has essentially the identical backbone conformation (0.41 Å RMSD of 235/271 C_αpositions and 0.65 Å RMSD of 270/271 C_αpositions) as ecRBP. Classification of the amino acid substitutions as a function of structure therefore allows the identification of amino acids which potentially contribute to the observed thermal stability of tteRBP in the absence of large structural heterogeneities.</p> <p>Conclusion</p> <p>The near identity of backbone structures of this pair of proteins entails that the significant differences in their thermal stabilities are encoded exclusively by the identity of the amino acid side-chains. Furthermore, the degree of sequence divergence is strongly correlated with structure; with a high degree of conservation in the core progressing to increased diversity in the boundary and surface regions. Different factors that may possibly contribute to thermal stability appear to be differentially encoded in each of these regions of the protein. The tteRBP/ecRBP pair therefore offers an opportunity to dissect contributions to thermal stability by side-chains alone in the absence of large structural differences.</p

Modelling of redox flow battery electrode processes at a range of length scales : a review

In this article, the different approaches reported in the literature for modelling electrode processes in redox flow batteries (RFBs) are reviewed. RFB models vary widely in terms of computational complexity, research scalability and accuracy of predictions. Development of RFB models have been quite slow in the past, but in recent years researchers have reported on a range of modelling approaches for RFB system optimisation. Flow and transport processes, and their influence on electron transfer kinetics, play an important role in the performance of RFBs. Macro-scale modelling, typically based on a continuum approach for porous electrode modelling, have been used to investigate current distribution, to optimise cell design and to support techno-economic analyses. Microscale models have also been developed to investigate the transport properties within porous electrode materials. These microscale models exploit experimental tomographic techniques to characterise three-dimensional structures of different electrode materials. New insights into the effect of the electrode structure on transport processes are being provided from these new approaches. Modelling flow, transport, electrical and electrochemical processes within the electrode structure is a developing area of research, and there are significant variations in the model requirements for different redox systems, in particular for multiphase chemistries (gas–liquid, solid–liquid, etc.) and for aqueous and non-aqueous solvents. Further development is essential to better understand the kinetic and mass transport phenomena in the porous electrodes, and multiscale approaches are also needed to enable optimisation across the relevent length scales

Differential interactions between chemokine receptors and G proteins

Chemokines are a large family of low-molecular weight cytokines, which regulate the chemotaxis of leucocytes and play an important role in immunological processes. Chemokine receptors utilize G Proteins for signaling. One remarkable feature in the chemokine field is the redundancy and promiscuity of both chemokines and chemokine receptors. Forty-five chemokines and eighteen chemokine receptors have been indentified to date. Most of the chemokine receptors can recognize multiple chemokines, and many chemokines are shared by several chemokine receptors. Chemokine receptors are typically coupled to Gi proteins, however, it remains unclear whether the chemokine receptors can interact with other G proteins. The extent by which different chemokines regulate G protein functions through a single chemokine receptor is also unclear. Hence, the interactions of six chemokine receptors CCR1, CCR2a, CCR2b, CCR3, CCR5 and CCR7 with G14 and G16 were studied in cotransfection systems. Results revealed that three of them, CCR1, CCR2b and CCR3 were coupled to both G14 and G16, while others could not. The potencies for five ligands of CCR1 (LKN-1, MIP-1α, RANTES, MCP-3 and MIP-1δ) to induce G14 and G16-mediated responses were then examined. Results showed that chemokines can differentially induce stimulation of phospholipase C via G14 and G16. Moreover, different chemokines differentially induced phosphorylation of the extracellular signal-regulated kinase ( ERK ) . ERK responses appeared to be regulated by both G14 and Gi proteins. Lastly, the possibility of CCR1 to signal through Gα14 and Gα16 was investigated in THP-1 and U-937 cells, which possess endogenous CCR1, Gα14 and Gα16. In these cells, CCR1 did not appear to mediate intracellular calcium release interact via Gα14 and Gα16. In summary, multiple chemokines may differentially regulate receptor-mediated signaling pathways and their receptors possess the ability to propagate the signals via G proteins other than those of the Gi family, although chemokine receptors might prefer to utilize Gi proteins in certain physiological systems

The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog-3

S 55–61, 2/residues 117–126, 3/residues 149–156). (B) Close-up view of the polar binding pocket residues in tteRBP (blue) and ecRBP (magenta). Ribose is shown in gray. Critical residues involved in ribose binding are indicated (where the tteRBP and ecRBP numbering are different, the former is given first). (C) Close-up view of the non-polar binding pocket amino acids of tteRBP (blue) and ecRBP (magenta). (D) Structural differences in the Cα positions of the aligned models of ecRBP and tteRBP generated by LSQMAN [60]. Dashed and dotted lines indicate the RMSD of 235/271 and 270/271 of the Cα atoms respectively of the aligned structures. The N- and C- terminal residues are indicated with a solid line. Loops and turns are indicated (asterisk), or loops (underlined asterisk) in the binding pocket region.<p><b>Copyright information:</b></p><p>Taken from "The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog"</p><p>http://www.biomedcentral.com/1472-6807/8/20</p><p>BMC Structural Biology 2008;8():20-20.</p><p>Published online 28 Mar 2008</p><p>PMCID:PMC2315655.</p><p></p

The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog-6

S). Thermal denaturation of ecRBP in the absence (open circle) or presence of 1 mM ribose (black circles). Solid lines in (A) are fit to a two-state model [31, 32] which takes into account the native and denatured baseline slopes. (B) Extrapolated of tteRBP in the absence (open squares) or presence of 1 mM ribose (black squares) obtained from a series of thermal melting curves at different GdCl concentrations. Solid lines represent linear fits to the observations.<p><b>Copyright information:</b></p><p>Taken from "The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog"</p><p>http://www.biomedcentral.com/1472-6807/8/20</p><p>BMC Structural Biology 2008;8():20-20.</p><p>Published online 28 Mar 2008</p><p>PMCID:PMC2315655.</p><p></p

The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog-0

underlined, amino acids that are conserved but not identical are in bold type (charge inversions are scored as non-conservative here). Core, boundary or surface classification of amino acids is shown below the aligned residues.<p><b>Copyright information:</b></p><p>Taken from "The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog"</p><p>http://www.biomedcentral.com/1472-6807/8/20</p><p>BMC Structural Biology 2008;8():20-20.</p><p>Published online 28 Mar 2008</p><p>PMCID:PMC2315655.</p><p></p

The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog-5

underlined, amino acids that are conserved but not identical are in bold type (charge inversions are scored as non-conservative here). Core, boundary or surface classification of amino acids is shown below the aligned residues.<p><b>Copyright information:</b></p><p>Taken from "The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog"</p><p>http://www.biomedcentral.com/1472-6807/8/20</p><p>BMC Structural Biology 2008;8():20-20.</p><p>Published online 28 Mar 2008</p><p>PMCID:PMC2315655.</p><p></p

The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog-2

Ted.<p><b>Copyright information:</b></p><p>Taken from "The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog"</p><p>http://www.biomedcentral.com/1472-6807/8/20</p><p>BMC Structural Biology 2008;8():20-20.</p><p>Published online 28 Mar 2008</p><p>PMCID:PMC2315655.</p><p></p

The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog-1

S). Thermal denaturation of ecRBP in the absence (open circle) or presence of 1 mM ribose (black circles). Solid lines in (A) are fit to a two-state model [31, 32] which takes into account the native and denatured baseline slopes. (B) Extrapolated of tteRBP in the absence (open squares) or presence of 1 mM ribose (black squares) obtained from a series of thermal melting curves at different GdCl concentrations. Solid lines represent linear fits to the observations.<p><b>Copyright information:</b></p><p>Taken from "The backbone structure of the thermophilic ribose binding protein is essentially identical to its mesophilic homolog"</p><p>http://www.biomedcentral.com/1472-6807/8/20</p><p>BMC Structural Biology 2008;8():20-20.</p><p>Published online 28 Mar 2008</p><p>PMCID:PMC2315655.</p><p></p

Immigration, transformation, and emission control of sulfur and nitrogen during gasification of MSW: Fundamental and engineering review

This paper proposes a comprehensive summary and analysis of an important issue during municipal solid waste (MSW) gasification-sulfur and nitrogen pollution. It provides an overview of the fundamentals of MSW and the basic aspects of nitrogen and sulfur elements. Their characteristics of immigration, transformation and distribution during gasification with control solutions in realized or potential engineering are also concluded. The analysis indicates that the complete scenario of the occurrence form of sulfur and nitrogen elements in MSW is difficult to obtain, owing to the diverse sources and complicated compositions. However, with the assistance of advanced characterization and quantification methods (XPS, XRD, TG-FTIR, et al.), the common sulfur- and nitrogen-containing compounds in both organic and inorganic states can be detected. Adjustment of gasification conditions can regulate the transformation of these elements for emission control. The multiple pollutants including H2S, SOx, COS, NH3, HCN and NOx cannot be eliminated by one-step treatment but a combination of adsorption and catalytic treatments may realize the control goal. This research aims to benefit meeting emission standards during MSW gasification and to provide a reference for other processes such as incineration, pyrolysis and other feedstocks like biomass and refuse derived fuel (RDF)