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Catherine L. Drennan. Higgins, Luke J. (Luke James) Massachusetts Institute of Technology. Dept. of Chemistry. Massachusetts Institute of Technology. Department of Chemistry 2008-02-28T16:25:14Z 2008-02-28T16:25:14Z 2005 2006 http://hdl.handle.net/1721.1/34497 70851986 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, February 2006. Vita. Includes bibliographical references. An X-ray crystallographic study of the fosfomycin biosynthetic enzyme hydroxypropylphosphonic acid epoxidase (HppE) from Streptomyces wedmorensis is presented. Structural analysis of this cupin mononuclear iron enzyme in complex with its in vivo substrate, and comparison with apo- and holo-enzyme structures, provides insight into the mechanism of fosfomycin biosynthesis. In vivo, the enzyme catalyzes the biosynthesis of the epoxide fosfomycin from its substrate, S-2-hydroxypropylphosphonic acid (S-HPP). In vitro, HppE is able to catalyze the conversion of the substrate enantiomer, R-2-hydroxypropylphosphonic acid (R-HPP), to a single ketone product in a stereospecific manner. X-ray crystal structures of HppE in complex with the R-HPP substrate suggest a mechanism for the regiospecific reactions catalyzed by the enzyme. This regiospecificity of HppE catalysis is also observed when substrates R- and S-2-phenylethlylphosphonic acid (HPEP) are used, where a methyl group has been substituted by a larger phenyl substituent. X-ray crystal structures in complex with S-HPEP suggest a conserved mechanism of regioselectivity and a mechanism of ligand rearrangement upon co-substrate (i.e. dioxygen) binding. Finally, HppE is compared to enzymes and proteins within the cupin superfamily, defining a new structural subfamily of cupin mononuclear iron enzymes. by Luke J. Higgins. Ph.D. 215 leaves eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Chemistry. Structural analysis of hydroxypropylphosphonic acid epoxidase : a fosfomycin biosynthetic enzyme Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="0dd0b1c2-6597-48b6-800d-40d0406988f2"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Structural analysis of hydroxypropylphosphonic acid epoxidase : a fosfomycin biosynthetic enzyme</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2006</PublicationDate> <Authors> <Author> <DisplayName>Higgins, Luke J. (Luke James)</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Chemistry.</Keyword> <Abstract>An X-ray crystallographic study of the fosfomycin biosynthetic enzyme hydroxypropylphosphonic acid epoxidase (HppE) from Streptomyces wedmorensis is presented. Structural analysis of this cupin mononuclear iron enzyme in complex with its in vivo substrate, and comparison with apo- and holo-enzyme structures, provides insight into the mechanism of fosfomycin biosynthesis. In vivo, the enzyme catalyzes the biosynthesis of the epoxide fosfomycin from its substrate, S-2-hydroxypropylphosphonic acid (S-HPP). In vitro, HppE is able to catalyze the conversion of the substrate enantiomer, R-2-hydroxypropylphosphonic acid (R-HPP), to a single ketone product in a stereospecific manner. X-ray crystal structures of HppE in complex with the R-HPP substrate suggest a mechanism for the regiospecific reactions catalyzed by the enzyme. This regiospecificity of HppE catalysis is also observed when substrates R- and S-2-phenylethlylphosphonic acid (HPEP) are used, where a methyl group has been substituted by a larger phenyl substituent. X-ray crystal structures in complex with S-HPEP suggest a conserved mechanism of regioselectivity and a mechanism of ligand rearrangement upon co-substrate (i.e. dioxygen) binding. Finally, HppE is compared to enzymes and proteins within the cupin superfamily, defining a new structural subfamily of cupin mononuclear iron enzymes.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>