Again, problems here are not your fault - the faults are those of the researchers and journals who write the abstracts in the 1st place. There are minor quibbles, such as authors' names or titles not reproduced exactly between journals and their on-line abstracts. Perhaps more severe is the lack of standard terminology. However, some people think it should be Major, not membrane. Some people omit intrinsic.
Some people say polypeptide instead of protein.
Some people say MIP26. Others say MP26. To find all the abstracts on my subject, I have to search for all these different permutations. Of course, what is really needed is for MIP26 researchers to sit down and standardise their terminology. Since this is unlikely to happen, my ultimate 'wishlist' would be for some form of neurally networked search engine, that would 'learn' that all such terminologies were really the same thing.