Preflop - you made a very big raise and got two callers. Unless they're both morons (which is possible at this buy-in), one of them has an ace or higher pair. I think you could have gained the same info by raising to $100 or so.

Flop - you bet 1/4 of the pot. This bet really didn't gain you any information about MP1s hand. You don't know whether he has an ace, a pocket pair or a flush draw. The problem is, if you bet more than 1/2 the pot, you've committed 1/2 your stack on this hand. I think you should either check or go all-in. I don't really like risking everything this early, with your hand and this flop, so I would probably check. If the turn was bet, I would probably fold. If the turn was checked and river was bet, I would call up to about 150.