PP $400nl - Nut Str on turn with possible flush on...

Stacks...
Villian is Loose Aggressive ($436)
Hero ($569)

Preflop: Hero is Mid Pos with A [img]/images/graemlins/diamond.gif[/img], K [img]/images/graemlins/heart.gif[/img]

UTG limps, Hero makes it $16 to go, Cutoff folds, Button (Villain) calls , Blinds and UTG folds...

Flop Q [img]/images/graemlins/spade.gif[/img] , T [img]/images/graemlins/heart.gif[/img] , 4 [img]/images/graemlins/spade.gif[/img] (pot $42)
I bet $25, Villain Calls

Turn brings J [img]/images/graemlins/spade.gif[/img] giving me the nut straight with 3 spades on board...
I bet $50....Villain makes it $175
I don't know what to do here.