Taking selfies with conference speakers I'm at a conference and I really enjoyed a plenary lecture by a speaker. 
His work resonated with some of the stuff I have been working on myself.

I have a Journal Club presentation coming up soon in my lab and I'm planning to present a few of his recent papers along with other perspectives in the field. Would it be ok to ask for a selfie at the conference dinner to put in the presentation? 

In general, is it acceptable to ask scientists for selfies? I doubt that it matters, but the field in question is protein chemistry.
Yes, it is acceptable. I heard a rumor that scientists are human beings. I have not been able to confirm it, but it seems like a plausible assumption, and if you are willing to accept this as a working hypothesis, it follows that it is acceptable to behave around them as you would with other human beings. 

In particular, most human beings are flattered if you approach them with excitement and admiration and ask to have your photo/selfie taken with them because you want to brag to your friends (or whoever) about meeting them, and would either happily agree or (less likely, but possible) politely refuse. Scientists - even protein chemists! - are no exception to this rule.