= Claire Debarnot
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<Claire Debarnot> is the first author of a 2019 structural study of human <heparosan-N-sulfate-glucuronate 5-epimerase>, an <enzyme> that modifies <heparan sulfate>. The reaction changes <glucuronic acid> residues into <iduronic acid> residues by <epimerization> at carbon five.<Substrate binding mode and catalytic mechanism of human heparan sulfate d-glucuronyl C5 epimerase by Claire Debarnot and others>[Original byline and Abstract]{ref}
The team combined <crystal structures> with real-time <nuclear magnetic resonance> measurements. An inactive mutant could bind defined carbohydrate substrates and products, allowing their positions to be examined without rapid conversion obscuring the comparison. The structures showed a bent chain and constrained sugar-ring conformations at the <active site>.<Substrate binding mode and catalytic mechanism of human heparan sulfate d-glucuronyl C5 epimerase by Claire Debarnot and others>[Abstract; Results, substrate/product complexes; Figures 1A and 2]{ref}
This approach connects shape and chemical activity. Binding a carbohydrate does not establish that an <enzyme> catalyses its conversion; the independent activity measurement tested that distinction. Conversely, the bound structures helped explain which local arrangements accompany the reaction.
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