Martyn F. Symmons is the first-named author of a 2000 structural study of polynucleotide phosphorylase. The collaborators' subsequent account gives his full byline, preserving the connection to the original M. F. Symmons credit.[ref]
The structure showed a duplicated core within each protein subunit and a three-subunit assembly. Bound tungstate, a phosphate analogue, helped identify a catalytic region; the structure did not contain bound RNA.[ref]
A simple counting example clarifies the architectural claim. A protein trimer with two related core protein domains per chain contains such domains but only three chains. The domain count alone does not establish six equivalent active sites. A repeated fold can retain a similar shape while acquiring a different catalytic or structural role.
This distinction suggests an experimental comparison: locate a bound chemical analogue, identify nearby amino acid residues, then compare functional measurements after controlled changes while independently checking protein folding. A loss of activity after global unfolding would not isolate the role of one active site. This is a general interpretation of the structural strategy, rather than an assignment of particular experiments to Symmons solely from author order.
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