Abstract
Alternaria alternata is a common airborne fungus that can be found in both indoor and outdoor environments. It is a major allergen linked to respiratory diseases such as allergic rhinitis and asthma. It may also infect the skin, nails, or eyes. In addition, uncharacterized or hypothetical proteins are present but have not yet been identified or associated with specific protein sequences. Domains of undetermined activity refer to molecules with known, experimentally determined activity. Yet, the exact role or structural features of these proteins have not been identified. Many proteins encoded in A. alternata genome remain uncharacterized, including the hypothetical protein XP_018378625.1 containing the SRC1lrK2f domain, whose function is unknown. This research employed a comprehensive in-silico approach to predict its physicochemical features, structural properties, subcellular localization, and protein-protein interactions and 3D structure. The protein was found to be hydrophilic, with an instability index of 46.62 and isoelectric point value of 6.41 which indicates acidic nature. The in-silico analysis indicated that the protein is soluble, with its secondary structure mainly composed of a random coil suggesting structural flexibility. The analysis showed that the protein contains a cytoplasmic domain. Moreover, the protein-protein interactions were examined using STRING software, which showed that the SRC1lrK2f protein has a strong interaction with exodeoxyribonuclease 1, implying a possible role in DNA repair or genome maintenance. These findings provide the first functional insights into the SRC1lrK2f domain in A. alternata and may support the future development of pharmaceutical strategies for managing Alternaria-induced allergic and infectious diseases by advancing our understanding of the biological role of the SRC1lrK2f domain.