Adenosine deaminase structure determination

As noted by Kati and Wolfenden, this remarkable affinity appears to suggest that the 6-hydroxyl group, which has very limited freedom of movement, is likely to be in almost ideal alignment with the active site, and that at least one charged active site residue is also likely to be involved in its hydrogen bonding interaction. This conjecture has since been verified by the determination of the crystal structure of the inhibitory complex between adenosine deaminase and 6-hydroxy-1,6-dihydropurine ribonucleoside, which showed that the 6-hydroxyl group interacts with a zinc atom, with a protonated histidyl residue, and with an aspartic acid residue at the enzyme s active site. 

Nachman, R.J., Wong, R.Y, Haddon, W.F., and Lundin, R.E. (1985) Synthesis of ara-doridosine, a new arabinosyl nudeoside resistant to adenosine deaminase. X-ray structure determination of methylisoguanine./. Chem. Soc. Perkin Trans. 1,1315-1321. 

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