Metalloenzyme structure and function
Abstract
Pentalenene synthase is the first terpenoid cyclase to yield a three-dimensional structure. The structure of this novel Mg$\sp{2+}$-dependent enzyme provides the first insights on how the cyclization of farnesyl diphosphate is triggered and how the enzyme channels and protects highly-reactive carbocation intermediates through a complex cyclization cascade. These insights are valuable for understanding the function of other terpenoid cyclases, such as those involved in cholesterol and steroid biosyntheses. Moreover, the greater family of terpenoid cyclases may share significant structural homology with pentalenene synthase, since they are chemically-related by the biogenetic isoprene rule and biologically related through the evolution of divergent biosynthetic pathways.^ The three Appendices contain X-ray crystallographic results on a series of direct and indirect ligand-substituted variants of carbonic anhydrase II. The structures of these variant enzymes is correlated with the spectrophotometric results of the functional aspects of this enzyme: these are zinc affinity, kinetics of metal association and dissociation, hydroxide stabilization by the enzyme active site and the rates of esterase and CO$\sb2$ hydrase activities. ^
Subject Area
Biology, Molecular|Chemistry, Biochemistry
Recommended Citation
Charles Andre Lesburg,
"Metalloenzyme structure and function"
(January 1, 1997).
Dissertations available from ProQuest.
Paper AAI9800889.
http://repository.upenn.edu/dissertations/AAI9800889
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