5/5/10 Live

Eff: $1,300

Hero (UTG+1) raises to $50 with red AAxx.
Three callers including Villain (SB).

Flop: ($210) As 3c 5s

Villain checks
Hero bets $175
Only Villain calls

Turn: ($560) As 3c 5s Tc

Villain checks.
Hero bets $500
Villain calls

River: ($1560) As 3c 5s Tc 9c

Villain bets $575 and is all in
Hero ??

Villain is pretty nitty preflop but has lost a couple of buy ins. Been a bit spewy today.
We're getting good odds to call but what does Villain call turn with and lead river that we beat?
Is this just a standard but gross fold as we beat nothing but a bluff and it's hard for him to be bluffing here?