Chuck Berry is always the first to acknowledge his influences-- Carl Hogan, T-Bone Walker, Charlie Christian, and on and on. I wrote about some of the others down below somewhere. Berry has always very specifically credited Louis Jordan's guitarist Carl Hogan for the famous intro to Roll Over Beethoven, Johnny B. Goode, and (just about every song at a live show!) You can find a nice version of Carl Hogan playing it on a 1946 cut called "Aint That Just Like A Woman," (Louis Jordan's Number Ones, 2005 Geffen Records). Hogan uses single strings for the intro, but you can hear the roots of CB in some of his solo stuff in the middle of the song. I couldn't find that on line, but here's a version from some sort of youtube copycat. The intro (on horns this time) might sound familiar!