如何在一序列中寻找E-BOX 元件，并将其变为小写
给定一个序列，寻找所有的E-BOX motif (CNNTTG) , 并且将其变为小写， 用 python 实现如下：
1 #!/bin/python 2 # Date: 2015.8.01 3 # Author: 4 """ Search E-box motif(CNNTTG) in a DNA seq and replace this motif with lower character """ 5 6 import re # using regular expression 7 8 dna_seq = open("/home/genome_seq.txt") 9 dna_test = open("/home/test_new.txt","w") 10 11 my_seq = "" # create a empity string not a list 12 for line in dna_seq: 13 my_seq = my_seq + line.rstrip("\n") # create a whole string with string concencating 14 # remove the "\n" 15 Ebox_motif = re.findall(r"C[TACG][TACG]TTG", my_seq) # use regular expression to find the motif 16 # use findall method to return a list contains the motif 17 seq = my_seq 18 19 for motif in Ebox_motif: 20 seq = seq.replace(motif, motif.lower()) # use str.replace() method **** the key step***** 21 22 dna_test.write(seq) # write the string to a file 23 dna_test.close() # good habit 24 dna_seq.close() # good habit
