TWO APPROACHES TO THE STUDY OF PROTEIN INTERACTIONS WITH SMALL MOLECULES: (A) STRUCTURAL ANALYSIS OF PYRIDOXAL L-PHOSPHATE BINDING ENZYMES (B) PURIFICATION, RECONSTITUTION, AND DRUG-BINDING CAPABILITIES OF THE PLASMODIUM FALCIPARUM MULTIDRUG RESISTANCE PROTEIN (PfMDR1)
Creator
Pleeter, Perri Gail
Advisor
Wolf, Christian
Vasudevan, Sona
Abstract
Structural genomics initiatives are producing new protein structures at a rate that will soon
exceed the rate at which biochemical experiments can validate their properties. In the near future,
there will be a need for faster methods of accurate identification of proteins and prediction of their
functions. Attempts to address this problem by functional prediction methods based only on protein
sequences are often limited in scope, as protein sequences diverge at very fast rates. In cases of highly
diverged proteins, structural approaches have proven more promising, as it is a well-known fact that
structures retain over longer evolutionary timescales than sequences alone. Hence, a combined
approach using both sequence- and structure-based methods seems ideal for function characterizations.
An estimated 4% of all enzymes utilize pyridoxal- 5&rsquo-phosphate (PLP) as a cofactor (1). The
majority of PLP-dependent enzymes (PLP-DEs) are involved amino acid biosynthesis, but also catalyze a
variety of other biological reactions. Nevertheless, PLP is surprisingly unique in its interaction with each
enzyme. PLP forms a conserved covalent linkage from its aldehyde group with the epsilon-amino group of a
lysine residue in the enzyme's binding pocket. The imine linkage between cofactor and enzyme is the
only commonality among all these enzymes. In some enzymes, PLP-DEs have evolved to accommodate
two distinct substrates-- amino group donors and amino group acceptors-- within the same binding
pocket, a unique feature for enzymes which typically can only recognize a single substrate.
Furthermore, PLP-DE can bind and utilize their cofactor in a stereoselective way (2).
Description
Ph.D.
Permanent Link
http://hdl.handle.net/10822/557530Date Published
2012Subject
Type
Embargo Lift Date
2015-05-02
Publisher
Georgetown University
Extent
226 leaves
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Metadata
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