Finding shortest list that contains all letters from a specific list of words. (Pangrams)

Question

I'm trying to find the fewest amount of words in a list that would make a Pangram. I.E contains all letters of the alphabet.

I can find words that contain a certain amount of letters that I've taken from another post but if I was looking for the fewest words from that list I would need to contain all letters of the alphabet how would I go about it.

This is where I am at the moment:

wordlist = ['mississipi','miss','lake','que']

letters = set('abcdefghijklmnopqrstuvwxyz')

for word in wordlist:
    if letters & set(word):
        print word

Any help would be great, Thanks