X-ray crystallographic studies of the metal binding sites on recombinant porcine fructose-1,6-bisphosphatase

dc.contributor.advisor Richard B. Honzatko
dc.contributor.author Choe, Jun-yong
dc.contributor.department Biochemistry, Biophysics and Molecular Biology
dc.date 2018-08-24T17:20:06.000
dc.date.accessioned 2020-07-02T05:44:51Z
dc.date.available 2020-07-02T05:44:51Z
dc.date.copyright Mon Jan 01 00:00:00 UTC 2001
dc.date.issued 2001-01-01
dc.description.abstract <p>Fructose 1,6-bisphosphatase (D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11, FBPase; Fructose 1,6-bisphosphate + H2O ⇔ Fructose 6-phosphate + Phosphate) is a key regulatory enzyme in gluconeogenesis. It is a homotetramer with subunit molecular mass of 37 kDa. There are two different quaternary conformations of FBPase: the R-state (the active conformation) and the T-state (the inactive conformation). FBPase is inhibited allosterically by AMP. FBPase requires divalent metal ions (Mg2+, Mn 2+, Zn2+, or Co2+) to hydrolyze fructose 1,6-bisphosphate. Some monovalent cations (K+, Rb+, Tl+ or NH3+) maximize the enzyme activity, whereas lithium ions inhibit the enzyme. Li+ inhibition of FBPase is similar to its effect on inositol monophosphatase, and, indeed FBPase and myo-inositol monophosphatase share a common polypeptide fold. FBPase is a target for the development of drugs in treating noninsulin dependent diabetes. A dynamic loop 52--72, revealed in a crystal structure of a product complex, and interacts with the active site of the enzyme. Loop 52--72 plays an important role in the allosteric mechanism, existing in two different conformations. A new divalent metal site and four monovalent metal sites were discovered. All of metal sites could be important in vivo. FBPase might select a combination of metals for activity in vivo. AMP competes with divalent metals and displaces loop 52--72 from the active site. Two distinct conformations for the 1-OH group of fructose 6-phosphate correspond to non-productive and productive states of ligation. Direct evidence for the existence of metaphosphate is presented in the active site of FBPase at near atomic resolution. The presence of the metaphosphate implies a dissociative mechanism in FBPase catalysis: The cleavage of the ester bond between atoms O-1 and P of the fructose 1,6-diphosphate precedes the nucleophilic attack of water.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/483/
dc.identifier.articleid 1482
dc.identifier.contextkey 6073830
dc.identifier.doi https://doi.org/10.31274/rtd-180813-11525
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/483
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/77507
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/483/r_3016697.pdf|||Sat Jan 15 00:27:59 UTC 2022
dc.subject.disciplines Biophysics
dc.subject.keywords Biochemistry
dc.subject.keywords biophysics
dc.subject.keywords and molecular biology
dc.subject.keywords Biophysics
dc.title X-ray crystallographic studies of the metal binding sites on recombinant porcine fructose-1,6-bisphosphatase
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication faf0a6cb-16ca-421c-8f48-9fbbd7bc3747
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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