Three dimensional structure prediction of fatty acid binding site on human transmembrane receptor CD36

CD36 is an integral membrane protein which is thought to have a hairpin-like structure with alpha-helices at the C and N terminals projecting through the membrane as well as a larger extracellular loop. This receptor interacts with a number of ligands including oxidized low density lipoprotein and long chain fatty acids (LCFAs). It is also implicated in lipid metabolism and heart diseases. It is therefore important to determine the 3D structure of the CD36 site involved in lipid binding. In this study, we predict the 3D structure of the fatty acid (FA) binding site [127–279 aa] of the CD36 receptor based on homology modeling with X-ray structure of Human Muscle Fatty Acid Binding Protein (PDB code: 1HMT). Qualitative and quantitative analysis of the resulting model suggests that this model was reliable and stable, taking in consideration over 97.8% of the residues in the most favored regions as well as the significant overall quality factor. Protein analysis, which relied on the secondary structure prediction of the target sequence and the comparison of 1HMT and CD36 [127–279 aa] secondary structures, led to the determination of the amino acid sequence consensus. These results also led to the identification of the functional sites on CD36 and revealed the presence of residues which may play a major role during ligand-protein interactions

Drought-tolerant sesame mutant lines assessed by physiological traits and stress indices under water deficit conditions

Climate change and water scarcity are the most important factors that affect crop production in dry areas. Sesame (Sesamum indicum L.) is a very ancient oilseed crop cultivated in arid and semi-arid regions and therefore its productivity is limited under drought conditions, which makes the selection and development of drought-tolerant cultivars imperative. This study aims to evaluate the responses to drought stress of eleven M4 sesame mutants, in addition to their two wild-type parents, cultivated in two contrasting environments. Drought stress was applied, under field conditions, by reducing the amount of irrigation water supplied by half, compared to the control. Physiological traits and various drought indices were measured/calculated. All data were subjected to analysis of variance and unweighted pair group method with arithmetic mean (UPGMA) to classify genotypes as drought sensitive or drought tolerant. Significant variations among genotypes were observed in their reactions to water regimes and environments. Overall, under water stress, proline content and stomatal resistance significantly increased, while chlorophyll content, seed yield, and relative water content significantly decreased in stressed plants. Drought indices revealed substantial differences among genotypes, with tolerant ones showing the best scores. Furthermore, correlation analysis demonstrated significant associations between physiological traits and drought indices. In light of all the traits/indices investigated, the mutant ‘US1-2’ was found to be very drought-sensitive, although it performed best under full-irrigation conditions. In contrast, the mutant lines ‘ML2-37’ and ‘ML2-37’ proved to be highly drought-tolerant and, therefore, they can be handled as an elite germplasm for the development of resilient cultivars adapted to arid and semi-arid regions where irrigation water is a limiting factor. This work constitutes a significant contribution to research on sesame drought tolerance and offers promising prospects for this crop in the context of global climate change