Jun 12, 2013 – NMR Topical Group Meeting

The North Jersey ACS NMR Topical Group proudly presents its June meeting of 2013 at Rutgers CABM on Wednesday, June 12, 2013.  [ register ][raw]

This meeting is sponsored by

Featured Speakers

Talk I
19F NMR as a Direct Probe of Intermolecular Interactions by Non-Structural Protein 1 from Influenza A Virus

James M. Aramini, PhD,

Research Assistant Professor, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ

Talk II
“Nexomics Biosciences”

Gregory Kornhaber, PhD,
Nexomics Biosciences, North Brunswick, NJ

Abstract for Talk I:

Non-structural protein 1 of influenza A virus, NS1A, is a key multifunctional virulence factor produced in the infected host cell that plays a critical role in evading the host antiviral response. This highly conserved hub protein in influenza infection is comprised of two domains: an N-terminal double-stranded RNA-binding domain (RBD) and a C-terminal effector domain (ED) which binds to a plethora of host cellular proteins. Isolated RBD and ED domains of NS1A both exist as homodimers in solution.

Since the 1960s, 19F has been recognized as a valuable NMR probe for biological systems due to its numerous favorable NMR properties, including its nuclear spin (I = ½), high natural abundance (100%), extremely high sensitivity, wide chemical shift range, minimal inherent background 19F signals, and the exquisite sensitivity of its chemical shift to changes in local environment.

Here we have applied 19F NMR to the study of NS1A from influenza A/Udorn/307/1972 (H3N2) virus. We incorporated 5-fluorotryptophan (5-F-Trp) into NS1A RBD, NS1A ED, and full-length NS1A, and assigned the 19F signals corresponding to the four Trp residues in this protein by site directed mutagenesis. We demonstrate that the 19F signal for W187, located in a functionally important helix-helix interface, can be used to monitor the oligomerization state of the ED (i.e., dimer to monomer transitions). Our 19F NMR data provide strong evidence in favor of conformational exchange at this critical interface in solution. Moreover, for full-length NS1A, 19F NMR provides the first direct spectroscopic evidence that W187, which is known to mediate intermolecular ED:ED interactions in the oligomerization of full-length NS1A, becomes solvent-exposed at protein concentrations below aggregation (ca. 50 %mu;M). Finally, we demonstrate that 5-F-Trp and 4-fluorophenylalanine (4-F-Phe) incorporation combined with 19F NMR serves as a sensitive approach for monitoring the binding of the F2F3 peptide from CPSF30 to NS1A ED.

This work was supported by grants from the NIGMS Protein Structure Initiative U54-GM094597 (to G.T.M.), NIH U01-AI074497 (to G.T.M. and R.M.K.), and NIH R01-AI11772 (to R.M.K.).

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