Ksiloglukan endotransglikozilaz/hirolaz enzimlerinin evrim orijinlerini incelemek için analizi

Xyloglucan is an important polysaccharide and is involved in strengthening the cell wall in both monocot and eudicot species. The xyloglucan endotransglycosylase/hydrolase (XTH) enzymes can degrade or remodel xyloglucan within the cell walls. The characterization of the xyloglucan substrates have a great importance since their involvements in the process of cell wall components and properties of the cell wall. The part of the cell wall where XTH enzyme shows activity, protects the plants from the outer elements and interacts with the environment. To be able to manipulate cell wall properties in order to enhance the yield and protect the plant from outer stresses, it is important to understand the functions of the enzymes that are modifying the carbohydrate matrix. XTH is one of the members of glycoside hydrolases 16 (GH16) enzyme family and it cleaves and re-ligate or irreversibly hydrolyzes xyloglucan. The aim of this study is investigating ancestral and EG16 group XTH enzyme members including OsXTH30, OsEG16-31 (Oryza sativa), BdXTH2 (Brachypodium distachyon), and HvEG16-10 (Hordeum vulgare). Heterologous expression, production and purification of the enzymes was performed as well as characterizing the enzymes and analyzing their kinetic studies. OsEG16-31, and HvEG16-10 enzymes could not be heterologously expressed during the period of this study, but XTH activity levels were detected from OsXTH30 and BdXTH2. The characterization of BdXTH2 enzyme showed higher affinity for tamarind seed xyloglucan as a donor substrate. The characterization and enzymatic activities of ancestral forms of XTH gene products is aimed since these genes have a role in seed germination, stress tolerance, organogenesis, cell expansion, and fruit ripening.