Thanks a lot Mensur! That's what I was looking for! I'm gonna try that package and see how it goes! Now it is clearer, it's logical to use a consensus sequence which comes from a HMM file!
Regards. Gerardo
Hi mates, I was reading a paper which it states they identify protein sequences in Halyomorpha halys genome performing a local BLASTp search using the PFAM domain (PF00112) as query (paper) It is driving me mad because I couldn't do it. The main doubt I have is how can I be able to add a PFAM domain as query in a BLASTp? is it that possible? Because PFAM domains are HMM and not a unique sequence.
The main idea behind it is to search for papain family cysteine protease domains in the proteome of Halyomorpha halys
Thanks in advance,
You are correct that BLASTp can't read HMM files, so it can't be done directly. Either an HMM has to be converted to a single protein sequence, or a search started with a seed alignment that is used to make HMMs.
hmmemit from the HMMer package can output a consensus sequence which would be suitable for BLASTp search. Below is a command for the PF01253 domain and its output:
hmmemit -c PF01253.hmm > PF01253.fas
more PF01253.fas
>PF01253-consensus
AKPKIHIRVEKRNGNKKVTLIRGLEGFGIDLEALAKDLKKKLACGGSVTKDPEKGKEIEI
QGDHRKEVAEFLLEKYGIP
You will most likely get a higher sensitivity by searching with hmmsearch and your HMM of interest against a Halyomorpha halys proteome, than with a converted FASTA sequence and BLASTp. There shouldn't be any major difference in speed either.
Thanks a lot Mensur! That's what I was looking for! I'm gonna try that package and see how it goes! Now it is clearer, it's logical to use a consensus sequence which comes from a HMM file!
Regards. Gerardo
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