Faculty Bibliography

The crystal structure of a dimeric 2:2:2 FGF:FGFR:heparin ternary complex at 3 A resolution has been determined. Within each 1:1 FGF:FGFR complex, heparin makes numerous contacts with both FGF and FGFR, thereby augmenting FGF-FGFR binding. Heparin also interacts with FGFR in the adjoining 1:1 FGF:FGFR complex to promote FGFR dimerization. The 6-O-sulfate group of heparin plays a pivotal role in mediating both interactions. The unexpected stoichiometry of heparin binding in the structure led us to propose a revised model for FGFR dimerization. Biochemical data in support of this model are also presented. This model provides a structural basis for FGFR activation by small molecule heparin analogs and may facilitate the design of heparin mimetics capable of modulating FGF signaling

A new class of protein tyrosine kinase inhibitors was identified that is based on an oxindole core (indolinones). Two compounds from this class inhibited the kinase activity of fibroblast growth factor receptor 1 (FGFR1) and showed differential specificity toward other receptor tyrosine kinases. Crystal structures of the tyrosine kinase domain of FGFR1 in complex with the two compounds were determined. The oxindole occupies the site in which the adenine of adenosine triphosphate binds, whereas the moieties that extend from the oxindole contact residues in the hinge region between the two kinase lobes. The more specific inhibitor of FGFR1 induces a conformational change in the nucleotide-binding loop. This structural information will facilitate the design of new inhibitors for use in the treatment of cancer and other diseases in which cell signaling by tyrosine kinases plays a crucial role in disease pathogenesis

A reliable high-performance liquid chromatography (HPLC) method is described for the separation of dimethylamino-azobenzenesulfonyl-amino acid (DABS-AA). The separation is accomplished by reversed-phase chromatography on a Hypersil ODS column (4.6 x 150 mm) with a Hewlett-Packard liquid chromatography system. In addition to the developed sample and solvent preparation procedure, this precolumn modification method using dimethylaminoazobenzene sulfonyl chloride (DABS-CL) for amino acid analysis is proved reliable and sensitive. Five apolipoprotein B-100 tryptic peptides, two of them containing cysteine, were demonstrated as examples for the general application of this method in amino acid analysis. It is a useful method for analysis of cysteine- and cystine-containing peptide and, furthermore, for determination of sulfhydryl and disulfide linkages of proteins.