Link to this post | posted 03 Aug, 2022 18:32

kcornely

Greetings all! We generated our R2I for Langerak and were pleased to see that we had assigned all functional assignments correctly except for one: Gene 46 (31633-32562). This gene belongs to pham 37230. On Phamerator, all of the other most closely related P1 cluster phages (Donovan, FirstPlacePfu, HUHilltop, Jebeks and Techage) all have this same pham, and the assigned function is RecB-like exonuclease/helicase. On the SEA PHAGES function list, we are told the following: RecB-like exonuclease/helicase: If both a helicase and nuclease domain are present, the RecB label should be used. Cas4-family exonuclease: This family of exonucleases is similar to the exonuclease domain of RecB. The Cas4 label should be used if the gene includes only the exonuclease region. IF the gene also includes a helicase domain, the RecB label should be used. Cas4 family nucleases tend to have alignments to the crystal structure 4R5Q_A, 41C1_A and to the PD-(D/E)XK nuclease superfamily (PF12705.7, among others) On HHpred for Langerak, we did get hits to the Cas4 family nucleases mentioned in the above paragraph. But we also got hits to helicases: 3U4Q_B, 4CEI_A, 6PPU_B, 1W36_E, and others. We decided to assign the function as the RecB-like exonuclease/helicase because (1) we thought we had fulfilled the requirement stated on the SEA PHAGES official function list that we should have hits to both helicases and exonucleases and (2) All of the other P1 cluster phages with the same pham used this functional assignment on Phamerator. But we were marked wrong. I'd like to get this right going forward, so could someone please help me out? As always, thanks for helping me "review to improve"! Best wishes, Kathleen

Link to this post | posted 11 Jul, 2022 20:36

kcornely

Greetings, all! We are annotating Frankenweenie, a BM cluster phage and had some questions regarding the interpretation of Starterator data. Here's an example: The start of gene 144 is called by Glimmer and GeneMark at 89678. This is also the suggested start on Starterator. But the most annotated start on Starterator is 89666 for all of the other five BM cluster phages. It also results in q1:s1 BLAST data for all of the other five BM cluster phages and as an added bonus, produces a -4 bp overlap and a gene length more in line with the other five BM cluster phages. So our question is: why are we seeing so many "suggested starts" on Phamerator for this phage that are not the same as the "most annotated" starts? And why, when we do choose the most annotated start (rather than the SS), it seems the better fit? Thanks in advance for helping me to understand Starterator better!

Link to this post | posted 11 Jul, 2022 18:38

kcornely

Greetings, all! I have another comment about the 4 bp overlap. We are annotating Frankenweenie, a BM cluster phage that has only six members total. We are occasionally encountering situations where it doesn't make sense to call the start at the position that provides a 4 bp overlap. For example, for gene 95, Glimmer and GeneMark call the start at 65479, which provides a 4 bp overlap. But to us, it makes sense to call the start at 65470. The 65470 start (1) is not the SS, but is MA on Starterator, (2) it provides us with q1:s1 BLAST his to the other five BM cluster phages, and (3) the product is similar in size to the other five BM cluster phages. I'd love to hear your insights on this observation, and thanks in advance!

Link to this post | posted 17 Jun, 2022 02:00
kcornely	Thanks Chris and Debbie! This is incredibly helpful.

Link to this post | posted 16 Jun, 2022 15:46
kcornely	Thank you Debbie! This is very helpful.

Link to this post | posted 16 Jun, 2022 15:45

kcornely

Greetings, all! We are annotating Frankenweenie, a Streptomyces BM cluster phage. We haven't annotated a BM cluster phage before. We were wondering if gp65 and gp66 were tail assembly chaperones and if gp66 was translated as a frameshift. There are six BM cluster phages, and the only phage in which the frameshift is called is Satis. It is not called for the other BM cluster phages. A frameshift seems likely for Frankenweenie because there is considerable overlap between gp65 and gp66. Thanks in advance for your help! Kathleen

Link to this post | posted 15 Jun, 2022 21:20

kcornely

Greetings, all! We are annotating a BM cluster phage, Frankenweenie. I have a team of four students working on this annotation project this summer. This is the first time that we've annotated a phage other than a mycobacteriophage, so we will be posting a lot of questions to the forum this summer! Our first question: Do Streptomyces phages have the 4 base pair overlap that is common in mycobacteriophages? I'm looking at gp30 now, and the BLAST data and the Starterator report fit better with a -1 bp overlap start. Should we go for the -4 bp start anyway? Thanks in advance for your help! Kathleen

Link to this post | posted 14 May, 2022 17:35
kcornely	Thanks for the speedy reply, Mitch!

Link to this post | posted 14 May, 2022 16:54

kcornely

Greetings, all! We are finishing up Langerak and checking our functions. gp4 has hits to the capsid maturation protease as well as ClpP-like proteases. On the SEA PHAGES official function list, we are told that sometimes the capsid maturation proteases has hits to ClpP-like proteases and in the notes, we are told "sometimes the CMP hits to ClpP proteases. If so, look for a serine-type endopeptidase activity". gp4 in Langerak does have hits to serine-type endopeptidase activity. To me, the directions aren't clear: If there are hits to endopeptidase activity does that mean that it is a ClpP-like protease? Or is it not a ClpP-like protease and we should assign "capsid maturation protease" instead? Thanks for help! Kathleen

Link to this post | posted 28 Mar, 2022 21:31

kcornely

Greetings, all! If you have a choice of a start that provides a single initial Met, or a start three bases earlier that would result in the translation of a protein with two methionines at the N-terminus, is there a rule regarding which start site is the correct one? Looking at the BLAST data for this particular gene, some annotators went with one Met and others went with two. Thanks in advance for the help! Kathleen