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phage helicase loader protein

| posted 31 May, 2018 17:39
I'd like to request adding this function to the approved list

The SPP1 phage helicase loader protein is a well-studies phage protein (see reference below).
I have seen good HHPred matches to this protein in a number of phages.

In Gordonia phage Rofo, gp 57 shows a couple of HHPred matches with 98% probability; 40-43% coverage and low E-values

Structural analysis of Bacillus subtilis SPP1 phage helicase loader protein G39P
Bailey, S., Sedelnikova, S.E., Mesa, P., Ayora, S., Waltho, J.P., Ashcroft, A.E., Baron, A.J., Alonso, J.C., Rafferty, J.B.
(2003) J.Biol.Chem. 278: 15304-15312
| posted 03 Jun, 2021 23:49
I am adding a response from Chris Shaffer:
I did a bit on this. Mostly on the question of nomenclature, not on the validity of the specific gene call. Because of this investigation, I am removing the DnaC-like helicase loader from the approved list.

I also ran across this site in poking around the web which is kinda interesting site:
https://proteopedia.org/wiki/index.php/DnaC_helicase_loader
It says there are two types of helicase loaders:
DnaC helicase loader (DnaC) transfers helicase to replication origins. The helicase loaders belong to two classes. The ‘ring breakers’ break the hexameric helicase to allow the DNA to pass through. The ‘ring makers’ assemble the helicase monomers to hexamers around the DNA.

Here is a good paper that summarizes these two methods: https://pubmed.ncbi.nlm.nih.gov/12906810/

Unfortunately, there is a complication in that the E coli DnaC is a breaker type and the B subtilis DnaC is a maker type so we have a name crash. This is the kind of thing that makes it really easy to make mis-assignments and/or cause a lot of confusion. If we say "DnaC-like" do we mean the E coli or B sublitis version. So I would argue for this situation, the best solution is to update the terms list to just "helicase loader" and avoid the "DnaC like".

I will note in my BLAST searches I found two Bacillus phage proteins that Veronique has published using the term "helicase loader" so she agrees with me.
 
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