[J.Copperthite]

This is a case of acting on your read - you figured he made a weak call on the flop w/ a gutshot w/ A-K and since this is the hand you believe he has, you fold on the river to save a bet. I'm all for acting on your reads - thats how you play the player - but in that spot the pot is just so large and you beat the majority of the hands he could have - he could have even called the flop bet w/ a hand as weak as A-9. My read on the SB was KQ when he checkraised, but since you threebet and he just flat called, I would immediately denounce that read and either have him on A-T or even A-J. If MP1 is as fishy as you say, he may even have something like Q-T, etc. Point is that even if you read him for the nuts, you must call getting 14 to 1 on your call. It is unlikely the SB will checkraise since he now checks the river - a checkraiser in micro-limits will almost always lead at the river if he still believes he has the best hand - his check tells me he is just as scared of the queen, so don't fear the checkraise. Hope this helps.