Watch the Turnaround 2 online guitar lesson by Joe Deloro from Blues Rock Road Trip 2
Phrase 2 is a four bar Q&A phrase with a straight eighth feel. Both motives start square on beat one of measures one and three. Steve Cropper's and Jimmy Page's styles are the basic context for Phrase 2. Motive one hints at Sam & Dave's, Soul Man and Motive two's descending sixths recall Led Zeppelin's, Heartbreaker.
The chord progression is E7,D7,A7,E7. Overall, the lead scale is the A mixolydian mode: A,B,C#,D,E,F#,G,A (1,2,3,4,5,6,b7,8) with C(b3) added. However, the overall tonality is a hybrid when the bass and lead parts are combined. Instead of a single note approach, harmonies of minor and major sixths make up the bulk of the sound.
In the first motive, G# is harmonized with E to function as the third (3) of E7, and also used as a passing note to D7. Both chords are actually borrowed from their own separate mixolydian modes.
The second motive is based on the A mixolydian mode. Sixth harmonies begin the motive and C(b3) and F(b6) are added in. G# is harmonized again with E. In the second measure the sound is based on single notes. C is used again to pass to C# and add some minor/major blues flavor. Be sure to check out the TAB variations for both phrases to extend each out to eight bar T&V periods. That way you'll be able to resolve on either the V (measure 4) or the I chords (measure eight).