Abstract:White spot syndrome and infectious hypodermal and haematopoietic necrosis are primary viral diseases of prawns. Outbreaks of white spot syndrome virus (WSSV) and infectious hypodermal and haematopoietic necrosis virus (IHHNV) arise worldwide and have caused serious economic losses in recent years, including in China. Some researchers found that, given the same conditions, WSSV-infected prawn display lower levels of mortality than IHHNV-infected prawn. Our laboratory previously demonstrated that IHHNV capsid protein (CP) has the ability to combine with NM23 protein in prawn gill membrane. NM23, a kind of nucleoside diphosphate kinase (NDPK), has various biological functions and is located mainly in the cytoplasm and nucleus, but is also evident in the cell membrane. We conducted an experiment to investigate whether WSSV and IHHNV compete with NM23 protein receptor sites on the cell membrane of shrimp gill tissue. First, we purified the total WSSV proteins using sucrose gradient centrifugation, and then we used a virus overlay protein binding assay (VOPBA) to detect protein-protein interaction between the total proteins and NM23. Next, three suspected positive proteins were selected by the combined LC-MS/MS technique: WSSV013, Wsv497 and Wsv035. Wsv035, also known as VP110, is one of the capsule membrane proteins of WSSV and is encoded by . It contains a membrane structure domain and a RGD locus (namely, the Arg-Gly-Asp motif). Some scholars, using fluorescence assay and competitive inhibition tests, found Wsv035 could stick to the host cell: Wsv035 RGD can form RGDT peptides at the cell surface and it plays a role in WSSV infection. There have been few studies of Wsv497 and WSSV013 proteins, however, and thus their distribution, structure and functions are not yet clear. Therefore, we constructed prokaryotic expression vectors of these three proteins, for purifying WSSV013, Wsv497 and Wsv035 in order to interact with NM23 protein, using VOPBA and co-immunoprecipitation, respectively. The results showed that Wsv497 and Wsv035 have the ability to interact with NM23, while WSSV013 showed an invalid effect on NM23. Accordingly, we surmise that WSSV and IHHNV have the ability to compete with NM23 protein receptors on the cell membrane of prawn gill tissue. This study adds to theories about the mechanism of competition between WSSV and IHHNV for receptor sites on the cell membrane of prawn gill tissue, and lays a foundation for further studies of protein interactions in the context of WSSV and prawn culture.