title: A pre-transition-state mimic of an enzyme: X-ray structure of adenosine deaminase with bound 1-deazaadenosine and zinc-activated water.
abstract: The refined 2.4-A structure of adenosine deaminase, recently discovered to be a zinc metalloenzyme [Wilson, D. K., Rudolph, F. B., & Quiocho, F. A. (1991) Science 252, 1278-1284], complexed with the ground-state analog 1-deazaadenosine shows the mode of binding of the analog and, unexpectedly, a zinc-activated water (hydroxide). This structure of a pre-transition-state mimic, combined with that previously determined for the complex with 6(R)-hydroxy-1,6-dihydropurine ribonucleoside, a nearly ideal transition-state analog, sheds new understanding of the precise stereospecificity and hydrolytic catalysis of an important and well-characterized member of a large group of zinc metalloenzymes. As both of these excellent mimics were generated in the active site, they demonstrate a powerful means of dissecting the course of an enzymatic reaction by direct crystallographic analysis.
authors.affiliation: Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030.
authors.forename: D K
authors.initials: DK
authors.lastname: Wilson
authors.forename: F A
authors.initials: FA
authors.lastname: Quiocho
mesh_terms: D000243:Adenosine Deaminase / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004926:Escherichia coli / Q000201:enzymology; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D051379:Mice; D015394:Molecular Structure; D014372:Tubercidin / Q000378:metabolism*; D014867:Water / Q000737:chemistry / Q000378:metabolism*; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014867:Water; C048086:1-deazaadenosine; D000243:Adenosine Deaminase; D015032:Zinc; D014372:Tubercidin