Need help on Turn

[ECAF REKOP]

I hope the converter worked, this is only my second posted hand. It's my understanding that my first post did not convert, although on my screen it looked as if it converted. Here go's:

Typical 2-4 party, Hero is in MPA w/AJo. Although the CO will play any two cards (mostly suited), not sure if she will cold call any two cards. Is this an easy fold on the turn? I am trying to clean up some leaks. I do not like folding heads up on the turn with TP when my oppenent raises on the scare card. Any thoughts?

Party Poker 2/4 Hold'em (9 handed)

Preflop:
UTG folds, UTG+1 folds, <font color="CC3333">MPA raises</font>, MP2 folds, MP3 folds, CO calls, Button folds, SB folds, BB calls.

Flop: (6.50 SB) A[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/spade.gif[/img] <font color="blue">(3 players)</font>
BB checks, <font color="CC3333">MPA bets</font>, CO calls, BB calls.

Turn: (4.75 BB) 5[img]/images/graemlins/heart.gif[/img] <font color="blue">(3 players)</font>
BB checks, <font color="CC3333">MPA bets</font>, <font color="CC3333">CO raises</font>, BB folds, MPA calls.

River: (8.75 BB) T[img]/images/graemlins/club.gif[/img] <font color="blue">(2 players)</font>
MPA checks, <font color="CC3333">CO bets</font>, MPA calls.

Final Pot: 10.75 BB

Results in white below: <font color="white">
MPA has Ac Js (one pair, aces).
CO has 8d 4h (straight, five high).
Outcome: CO wins 10.75 BB. </font>

[butters]

No way you should be behind on the turn here, unless you were cold-called by pairs 22 - 55. I'd be tempted to three-bet the turn here; definitely not folding.