DESCRIPTION OF RESEARCH PROJECTS
FTIR Analysis of Protein Secondary Structure:
Albumin, abundant in blood, is a major transport protein for endogenous
and exogenous components of the circulatory system. X-ray diffraction
studies revealed the heart shape of this molecule composed of three homologous
domains. Interactions of the domains of this highly helical
(66%) protein stabilized by numerous disulfide bonds are loosened
by manipulation of the solution environment. In general, the broad
spectrum of drugs, such as aspirin, diazapam, and AZT, traveling the circulatory
system bind to one of two sites located in helical subdomains IIA
and IIIA. We are using FTIR, sensitive to changes in
protein secondary structure, to monitor alterations in structure
in response to changing solution conditions and drug binding.
FTNMR Studies of Ligand Binding to Proteins:
A) Preliminary results of two dimensional H1 noesy experiments of nucleotide
bound to tubulin when subjected to molecular modeling analysis indicate
a predominantly anti-oriented guanine base coupled to an envelope conformation
of ribose. This ribose conformation differs from the twisted forms
commonly found in nucleic acids. Current investigations focus
on the conformation of GTP, free and unbound in solution.
B) Noesy experiments are used to investigate the conformation of drugs
bound to albumin with attention to benzodiazepines and nucleotides.
Although Valium is the most widely known benzodiazepine, this class of
pharmaceuticals have a wide spectrum of biological activity, such as anticonvulsant
and anti HIV reverse transcriptase action. Although the
benzodiazepines and nucleotides , such as AZT, nominally bind to the same
IIIA, they are substantially different structures expected to have
unique bound conformations that distinguishable interactions with amino
acid residues within the general binding site.