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Tail assembly chaperones in B phages

| posted 18 Jul, 2017 17:19
There are a number of B1 phages that have tail assembly chaperones called (Pham 10859 and pham 26552) but most have called as NKF. There is no evidence of a slippery sequence so these calls are made as two completely separate tail assembly chaperones. The position is generally right for this but it appears these calls are made based on one example in the phagesdb blast search and the HHPRED data are supportive of call such as tail protein for pham 10859 and nothing phage like for pham 26552. Any advice?
| posted 19 Jul, 2017 16:16
So I think this comes from the idea that there must be tail assembly chaperones in the Bs, and the most likely candidates are the genes between the major tail and tape measure proteins. We need two adjacent ORFs that are not in the same frame that have an overlap. Then, there are only two choices, the equivalent of FriarPreacher genes 22/23 or 25/26. 25 belongs to pham 10859, and has the hhpred hit to a tail protein (although it is the capping protein and not the assembly chaperone.) 22 also hits to some phage structural proteins that are not the assembly chaperones. Perhaps the best thing to do is to scrap all the TAC assignmnets in the Bs and set them all back to NKF.
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