Biochemistry, Biophysics, and Structural Biology Commons^™

Probing Large Intrinsically Disordered Regions Through Novel Sortase-Mediated Ligation, Leah Kjormoe

Scholars Week

In the realm of proteins, it is widely accepted that structure informs function. However, there are many proteins that contain intrinsically disordered regions (IDRs). These regions are areas in which the protein lacks defined structure, and IDPs are also often unstable, which complicates structural studies. NMR spectroscopy is an established method for probing protein structure and has been applied to that end in small IDRs. However, larger IDRs often have spectral overlap that makes data difficult to interpret. Furthermore, low-concentration samples limit spectral clarity. One method to address these difficulties is to use sortase ligation and segmental labeling, which increases …

Structure Determination Of A Bioengineered Human/Porcine Factor Viii For Hemophilia A Treatment, And Improvements To The Human Factor Viii Model, Ian Smith

Graduate Student Symposium

Blood coagulation factor VIII (FVIII), is a non-enzymatic cofactor which plays a crucial role in the formation of a stable blood clot. Absence or deficiency of FVIII results in the blood disorder hemophilia A; with symptoms including internal hemorrhaging and the inability to stop bleeding from open wounds. Treatment of hemophilia A relies on infusions of blood, plasma, or protein concentrates to replace FVIII. Unfortunately, approximately 30% of patients receiving replacement FVIII generate pathologic anti-FVIII inhibitory antibodies, which both reduce the effectiveness of the FVIII therapeutic and increase the severity of hemophilia A symptoms.

We have determined the molecular structure …

A Chemoenzymatic Approach For Synthesizing Polymeric Hemoglobin, Johann P. Sigurjonsson

Graduate Student Symposium

Polymerized hemoglobin (Hb) molecules have been shown to decrease previously observed adverse events associated with the administration of cell-free hemoglobin. To create these polymers, a method will be developed which employs the site specific ligation reaction of the sortase A enzyme from S. aureus. An Hb mutant (“αcpβ“) previously developed in our lab has been further modified by adding either the sortase recognition sequence, LPXTG, to the C-terminus of the α-subunit (s-αcpβ), or a tetraglycine motif, GGGG, to the N-terminus (n-αcpβ). Three types of sortase mediated ligation (SML) will be employed in this study. First, we will attempt to ligate …

Substrate Analogs For Characterizing The Substrate Tolerance Of S. Pneumoniae Srta, Orion Banks

Graduate Student Symposium

Bacterial sortases have been widely studied for their usefulness in protein modification, however, the variable substrate specificity and activity between homologs of these enzymes is not yet fully characterized. To attempt to further understand sorting signal recognition, we are working towards a substrate bound structure of sortase A from Streptococcus pneumoniae (SrtA_pneu). This enzyme displays a wide tolerance for alternate amino acids within the canonical LPXTG sorting motif. Our strategy involves a non-cleavable substrate analog that can be docked into the active site, allowing for elucidation of a structure displaying the key contacts that allow the enzyme …

Regulation Of The Ampa Glutamate Receptor Homolog Glr-1 At The Endoplasmic Reticulum In C. Elegans., Sam Witus, Lina Dahlberg

Scholars Week

In C. elegans, the glutamate receptor GLR-1 functions in the nervous system to decode environmental stimuli and sensory experiences, and to regulate locomotion and the formation of long-term memory. C. elegans GLR-1 is homologous to mammalian glutamate receptors, and we can use this simple organism as a system to better understand the life cycle of human receptors (1). Because GLR-1 is a membrane protein, it is first assembled in the interior of a neuron, and then it is transported to the membrane at the surface of the cell so that it can receive chemical signals (glutamate) from the environment. Currently, …