With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding the research of Dr. Kamil Godula at the University of California – San Diego, to study the effects of two human enzymes known as Sulf1 and Sulf2. These enzymes act on the exterior of cell surfaces by recognizing and modifying the patterns of negatively charged groups on sugar polymers that are part of the outside coating of cells. In doing so they control the activity of proteins involved in critical cell signaling and development events. Despite being a key element in regulating important cellular functions, the structures of these enzymes and the sugars they act on are still poorly understood. Additionally, their precise actions in a cellular context need better understanding. This research project develops a set of new tools and techniques at the interface of chemistry and biology to fill the gaps in the basic understanding of the biological functions of these enzymes. These activities allow graduate students to obtain training in the interdisciplinary area of chemical biology focusing on carbohydrate chemistry and biology. The students also gain a deeper understanding of the varied roles of carbohydrates in biology. The educational and technical resources enabled by this award allow for the dissemination of the knowledge, tools, and techniques stemming from this research project to the broader research community and the general public.
This research develops novel methods to produce human sulfatase enzymes enabling detailed investigations of structure and mechanism. New chemical glycomics tools are envisioned to capture and structurally characterize the polysaccharide substrates for these enzymes. Further, biochemical and cell-based assays are under development to investigate their function during embryonic stem cell differentiation. The sulfatase enzymes are thought to have specificity for unique negatively charged regions of their sulfated polysaccharide substrates complementing the organization of positively charged residues in their substrate-binding domains. However, little information exists regarding the structure of the enzymes and the composition of their preferred substrates. Arrays comprising structurally defined sulfated polysaccharides from synthetic and biological sources are in use to identify preferred substrates for the sulfatase enzyme isoforms and to delineate how the enzymatic removal of sulfates from the polysaccharides impacts their interactions with growth factors. The chemical toolbox includes substrate-based fluorogenic probes for imaging sulfatase activity in biological environments and reactive molecules for chemical fingerprinting of substrates for structural characterization by mass spectrometry analysis. In combination, these tools are deployed to map how sulfatase enzymes control growth factor signaling during neural and mesenchymal differentiation of murine embryonic stem cells. The tools are general and suitable for the investigation of other biological systems where extracellular sulfatases exert important regulatory functions.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
