protein_set = {
- site-specific DNA-methyltransferase,
- LysR family transcriptional regulator,
- helix-turn-helix domain-containing protein,
- efflux transporter outer membrane subunit
}
STEP 1 - Get the set of bactria species which have all 4 proteins in protein_set
STEP 2 - Download the gene sequence of species in common_bacteria_set
STEP 3 - Extract gene sequence of each protein for each species and write them to homologous_gene_sequences
STEP 4 - Build trees