{HEAD ~ A C terminal extension} of {TAIL ~ ST} are said to be in position number 275a and 275b, respectively, although, again, of course they have their own “real” position number in the variant amino acid sequence 
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{ HEAD ~ A C terminal extension } of { TAIL ~ ST } are said to be in position number 275a and 275b , respectively , although , again , of course they have their own “ real ” position number in the variant amino acid sequence
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH