Nut straight, board pairs on turn...

Villan was 40/15/ and had no problem raising and betting with middle pairs and underpairs. I think he could take this line w/ many aces. I decided at the turn to check since I wanted to get to a showdown cheaply if beat and it also encourages him to donk-bluff the river. His large river bet was disapointing. (The 2/3 pot flop bet was intentional - the table had been weak-tight and I had not been getting action and I had the nuts.... for a moment. OK, I donked it.

1) how's my line?
2) is this a fold?

PokerStars No-Limit Hold'em, $1.00 BB (6 handed) FTR converter on zerodivide.cx (http://www.zerodivide.cx/converter)

Button ($96)
SB ($109.10)
BB ($308.55)
UTG ($61)
Hero ($136.10)
CO ($55.85)

Preflop: Hero is MP with K/images/graemlins/club.gif, Q/images/graemlins/heart.gif.
UTG calls $1, Hero calls $1, <font color="#666666">3 folds</font>, <font color="#CC3333">BB raises to $3</font>, UTG calls $2, Hero calls $2.

Flop: ($9.50) A/images/graemlins/club.gif, T/images/graemlins/diamond.gif, J/images/graemlins/diamond.gif <font color="#0000FF">(3 players)</font>
BB checks, UTG checks, <font color="#CC3333">Hero bets $6</font>, BB calls $6, UTG folds.

Turn: ($21.50) A/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font>
BB checks, Hero checks.

River: ($21.50) 2/images/graemlins/club.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $25</font>, Hero?

Check behind on turn is ok but i think i would feel a little sick calling the overbet. It seems villans trying to get the value out of his hand that he failed to pick up on the turn cr. Judgement call, but i think i may make it since he could have been doing this with alot of hands. Ax,busted draw,2 pair.