structural insights into n terminal to c terminal interactions and implications for thermostability of a β α 8 triosephosphate isomerase barrel enzyme

Although several factors have been suggested to contribute to thermostability, the stabilization strategies used by proteins are still enigmatic. Studies on a recombinant xylanase from Bacilllus sp. NG-27 (RBSX), which has the ubiquitous (beta/alpha)(8)-triosephosphate isomerase barrel fold, showed that just a single mutation, V1L, although not located in any secondary structural element, markedly enhanced the stability from 70 degrees C to 75 degrees C without loss of catalytic activity. Conversely, the V1A mutation at the same position decreased the stability of the enzyme from 70 degrees C to 68 degrees C. To gain structural insights into how a single extreme N-terminus mutation can markedly influence the thermostability of the enzyme, we determined the crystal structure of RBSX and the two mutants. On the basis of computational analysis of their crystal structures, including residue interaction networks, we established a link between N-terminal to C-terminal contacts and RBSX thermostability. Our study reveals that augmenting N-terminal to C-terminal noncovalent interactions is associated with enhancement of the stability of the enzyme. In addition, we discuss several lines of evidence supporting a connection between N-terminal to C-terminal noncovalent interactions and protein stability in different proteins. We propose that the strategy of mutations at the termini could be exploited with a view to modulate stability without compromising enzymatic activity, or in general, protein function in diverse folds where N and C termini are in close proximity. Database The coordinates of RBSX, V1A and V1L have been deposited in the PDB database under the accession numbers 4QCE, 4QCF, and 4QDM, respectivel

Diabetic muscle infarction

Diabetic muscle infarction is an underdiagnosed and underreported complication of long-standing diabetes mellitus occurring in a middle-aged person with symptoms simulating infective or inflammatory condition most commonly involving the thigh muscles, legs, and arms, in decreasing order of frequency. Magnetic resonance imaging is the diagnostic modality of choice showing diffuse hyperintense signal involving the muscles and deep fascia on T2 images. It is a self-limiting condition which resolves simply by rest and analgesic; therefore, being aware of this condition is necessary to avoid unnecessary interventions

Wildlife Tourism Entrepreneurs the Way Ahead in Attaining Sustainability

In recent years, there has been a growing recognition of the importance of the link between sustainability and entrepreneurship. Wildlife tourism is one area where there is a high degree of involvement of the entrepreneurial sector, and in many instances there is a budding appreciation of the role played by these entrepreneurs towards sustainable tourism. However, there are cases where they fail to comply with the sustainability goals. This article discusses the connection between these entrepreneurs and the issues of sustainability, problems they face in adopting sustainable business practices and measures that are essential for them towards realizing the goal of sustainable tourism

Emerging role of N- and C-terminal interactions in stabilizing (β/α)8 fold with special emphasis on Family 10 xylanases

Xylanases belong to an important class of industrial enzymes. Various xylanases have been purified and characterized from a plethora of organisms including bacteria, marine algae, plants, protozoans, insects, snails and crustaceans. Depending on the source, the enzymatic activity of xylanases varies considerably under various physico-chemical conditions such as temperature, pH, high salt and in the presence of proteases. Family 10 or glycosyl hydrolase 10 (GH10) xylanases are one of the well characterized and thoroughly studied classes of industrial enzymes. The TIM-barrel fold structure which is ubiquitous in nature is one of the characteristics of family 10 xylanases. Family 10 xylanases have been used as a “model system” due to their TIM-barrel fold to dissect and understand protein stability under various conditions. A better understanding of structure-stability-function relationships of family 10 xylanases allows one to apply these governing molecular rules to engineer other TIM-barrel fold proteins to improve their stability and retain function(s) under adverse conditions. In this review, we discuss the implications of N-and C-terminal interactions, observed in family 10 xylanases on protein stability under extreme conditions. The role of metal binding and aromatic clusters in protein stability is also discussed. Studying and understanding family 10 xylanase structure and function, can contribute to our protein engineering knowledge

TiO₂–CeO₂/Ag Composite as Electrode Material for Supercapacitors

Electrochemical energy technologies play a pivotal role in the quest for a sustainable and cleaner future owing to their remarkable potential to revolutionize the way we generate, store, and utilize energy. In this context, the present study explores the synthesis and characterization of TiO2–CeO2 composites having surface-dispersed silver nanoparticles (TiO2–CeO2/Ag) as an efficient electrode material for supercapacitor application. The developed electrode materials are systematically characterized by using different techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical performance of the electrode materials is assessed by using cyclic voltammetry, galvanometric charge–discharge, and electrochemical impedance spectroscopy. The obtained results show that the electrode material with 2 wt % Ag distributed over TiO2–CeO2 composites (TiO2–CeO2/Ag 2X) is the best material with the highest specific capacitance of 996 F/g and excellent cycling stability even after 2500 cycles. The obtained results give clear credence to the idea that the TiO2–CeO2/Ag composites could serve as an efficient electrode material for energy storage applications