Proteolytic Analysis of Epsilon 34 Phage Tailspike protein indicates Partial Sensitivity to Proteinase K

Abstract

Purified bacteriophage Ɛ34 tailspike protein (Ɛ34 TSP) can bind to Salmonella newington (S. newington) via the binding site of the protein, which is the O antigens of the LPS of the bacterium. We demonstrated elsewhere that purified Ɛ34 TSP possessed bacteria lytic property on S. newington. The Ɛ34 TSP has been shown via computational prediction to consist of parallel β-helices like that of P22 TSP. These protein moieties are among the simplest repetitive structural elements in proteins. There exist extensive research on the folding behavior of β-helix proteins, which also provides insight on how amyloid fibrils are generated since these proteins consist of similar parallel β-helix motifs. One of the most significantly studied system for investigating protein folding is the from the Salmonella bacteriophage P22. The major component of this protein is a right-handed parallel β-helix with 13 rungs. Initial in silico analysis of the Ɛ34 phage TSP indicates similar structural similarity to the P22 TSP. Our previous studies indicated that despite the similarities of the two proteins, P22 TSP shows higher resistance to proteases (e.g. trypsin) and heat compared to Ɛ34 TSP. In this study we further proof that Ɛ34 TSP is partially sensitive to proteinase K, whereas P22 TSP is completely resistant to this protein. Detailed analysis indicates that specific structural motifs of Ɛ34 TSP is insensitive to the protease, whereas other regions of the protein showed susceptibility to it.