Blues riff

Hi all!!!!

Been looking for the classic blues riff that everyone knows. It's used in lots of blues songs. I think I came up with too much stuff and can't really figure it out. Best example is in Hoochie Coochie Man by Muddy Waters. The main riff du dun na du dunt. Hope that makes sense. I sorta came up with this but doesn't sound quite right on the acoustic.

E|---------------|---------------|
B|---------------|---------------|
G|---------------|---------------|
D|---------------|---------------|
A|---5-----7------|---------------|
E|-5---5-8---------------------|