3/6... AK donkish turn fold??

[tcorbin16]

Villian is 20/15 TAG. pretty good reg, he seems to get the better of me. my image is prob tag right now too.... Thoughts..?

Full Tilt Poker - No Limit Hold'em Cash Game - $3/$6 Blinds - 5 Players - (LegoPoker HH Converter)

SB: $1,175.85
BB: $428.05
UTG: $1,347.40
Hero (CO): $760.75
BTN: $860.75

Preflop: Hero is dealt A[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/diamond.gif[/img] (5 Players)
UTG folds, <font color="red">Hero raises to $21.00</font>, BTN folds, SB calls $18.00, BB calls $15.00

Flop: ($63) 4[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/spade.gif[/img] 2[img]/images/graemlins/spade.gif[/img] (3 Players)
SB checks, BB checks, <font color="red">Hero bets $45.00</font>, SB calls $45.00, BB folds

Turn: ($153) 7[img]/images/graemlins/diamond.gif[/img] (2 Players)
SB checks, <font color="red">Hero bets $120.00</font>, <font color="red">SB raises to $270.00</font>, Hero folds
Uncalled bet of $150.00 returned to SB

Pot Size: $393.00 ($3 Rake)