His glass chin wouldn't be a problem in MMA. I don't think anyone would be foolish enough to try to box him and if they did they wouldn't land on him. His zero grappling skills would be much bigger problem for him. Frankie Edgar would ragdoll him with ease. I still think Khan could beat heavily boxing oriented MMA fighter like McGregor with 6 months of grappling training.
MMA fighters mostly have pure china chins, I think that even those elite boxers who're considered to have glass jaws here would have solid chins for MMA standards. I mean just look at how many MMA fights end with flash KOs, often in 1st or 2nd round. Those guys have zero defense, they're mostly grapplers who never had their chins tested before they started MMA. I don't see any MMA fighter around his size surviving 12 rounds of punishment by Maidana. Aldo was P4P #1 and was knocked out by literally the 1st punch of the fight. McGregor was on the verge of doing the Zab Judah dance after getting slapped by Nate Diaz.
CM Punk would brutally KO Khan, he weighs like 70 pounds more. Personally I'd love to see Khan Vs. Lesnar.:hey
CM Punk will fight at 170, he's skinny and non-athletic, he's not like other pro wrestlers who're roided to the gills and weigh 300 pounds like Brock Lesnar. Khan would batter CM Punk
He's 185 which is in the MMA MW limit, Punk is at least 5 inches taller and will still have 25 to 30 pounds on Khan, if Algieri can rock him, Punk can too.
Punk doesn't know how to punch. He had no training in any martial art/combat sport before 2014 and he has no athletic background. He's just like any random 30 year old who started training boxing to get in shape except that he also trains grappling and other aspects of MMA, thus devoting even less time to boxing. MMA has a long learning curve and at this point he's a total rookie at everything. He'd have no chance to hurt Amir Khan, his only chance would be to somehow submit him with his beginner's grappling. I doubt he'll ever fight in the UFC anyway, this was just some PR stunt.
Punk's been practicing Brazilian Jiu Jitsu for years, he's trained under Rener Gracie, that's all he'd need to submit Khan's fragile weakling ass.
Rener Gracie who trains some celebrities and hands out belts via internet. CM Punk was a white belt when he signed with the UFC, I doubt that his beginner's grappling would be enough to submit Khan, he'd eat some boxing combo and panic. He's not a fighter and he's not an athlete. I think any male in UFC beats him, even those midgets.