HU with ATs, K on turn

[LowDown22]

Only been at table a few hands, so no good reads. I have trouble deciding when to call down and when to fold in heads-up hands like this. Mainly concerned with the turn play here. Can I give him credit for a King here or do I need to call down?

Paradise Poker 1/2 Hold'em (8 handed) converter

Preflop: Hero is MP1 with A[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/spade.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls, <font color="#CC3333">Hero raises</font>, <font color="#666666">5 folds</font>, UTG+1 calls.

Flop: (5.50 SB) T[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">UTG+1 bets</font>, <font color="#CC3333">Hero raises</font>, UTG+1 calls.

Turn: (4.75 BB) K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">UTG+1 bets</font>, Hero calls.

River: (6.75 BB) K[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">UTG+1 bets</font>, Hero calls.

Final Pot: 8.75 BB