Function and structure of the spike H protein of bacteriophage φX174 directing infection to host cell

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Contribution of lipid part of LPS to the recognition by spike H proteinThe LPS of E. coli C was treated with hydradine and potassium hydroxide to gave the deacylated derivatives of LPS. The derivatives showed significantly less affinity and small magnitude of conformational change toward the spike II protein of bacteriophage φX174 Contribution of charged residues of LPS to the recognition by spike H and G proteinsThe derivatives of dephosphorylated and KDO reduced derivatives were prepared by the limited chemical degradation of LPS by hydrogen fluoride and sodium borohydride coupled with water soluble carbodiimide. These derivatives were submitted to the estimation of the interaction with the spike H and G proteins. The H protein was affected by the loss of phosphate residue and the G protein was affected by the loss of KDO residue from the LPS for the recognition.Isolation and characterization of the protease resistance domains of spike H proteinBy a mild treatment with VS protease, H protein gave two protease resistant domains(F2 and F3). The observations of N-terminal amino acid and MALDI-TOF-MS analyses revealed that. F2 corresponded to the fragment of 215-345 residues, on the other hand, F3 corresponded to the fragment of 1-102 residues of H protein. The fragment F2 showed strong affinity toward the LPS of host bacteria compared to the intact H protein, however, the fragment Fl showed 1/10 affinity to the intact H protein.