Understanding the origins of protein conformational behavior is a longstanding goal in biomolecular science because protein function often depends upon proper folding, and aberrant protein behavior can lead to human disease. Although much progress has been made, many important questions remain unanswered. Our program focuses on problems that benefit from, and in some cases require, the application of unconventional chemical strategies (involving synthesis of unnatural subunits and polypeptides) in concert with traditional tools of biophysics. One long-term effort involves the development of molecules that fold autonomously to parallel ?-sheet secondary structure in aqueous solution, which represent unique tools for assessing structure-stability relationships for parallel ?-sheet secondary structure in the absence of a specific tertiary context. Proposed studies include a novel initiativ to add a third dimension to autonomously folding ?-sheets by creating "mini-solenoids", which would represent small segments of amyloid-like structure. These molecules are intended to enable us to probe amyloid packing phenomena via powerful solution-phase analytical methods. A second long-term effort involves a focus on coiled-coil interactions. The proposed research includes an effort to apply basic insights on coiled-coil pairing preferences to develop inhibitors of a protein assembly that underlies Streptococcal toxic shock. A third component of the proposed research involves application of racemic and quasi-racemic crystallography to acquire high-resolution insight on structural phenomena that are otherwise difficult or impossible to study. We propose to use racemic crystallography to characterize homo- and heterotypic associations involving transmembrane helix segments of cell-surface receptors. Such information is currently inaccessible, which hinders our understanding of signal transduction mechanisms. We propose to use quasi-racemic crystallography to identify guidelines for mimicking protein structural motifs with backbones that contain unnatural subunits. These studies could lay a foundation for rational engineering of novel biomedical agents.

Public Health Relevance

Proteins carry out most molecular-level tasks in living systems, and protein function usually depends on adoption of the proper shape. Our research is intended to reveal the factors that control common structural motifs in normal proteins, to elucidate the origins of improper protein folding (amyloid formation), and to establish guidelines for the design of protein-like molecules that might ultimately have therapeutic uses.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Synthetic and Biological Chemistry B Study Section (SBCB)
Program Officer
Smith, Ward
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Wisconsin Madison
Schools of Arts and Sciences
United States
Zip Code
Laaser, Jennifer E; Skoff, David R; Ho, Jia-Jung et al. (2014) Two-dimensional sum-frequency generation reveals structure and dynamics of a surface-bound peptide. J Am Chem Soc 136:956-62
Hayouka, Zvi; Mortenson, David E; Kreitler, Dale F et al. (2013) Evidence for phenylalanine zipper-mediated dimerization in the X-ray crystal structure of a magainin 2 analogue. J Am Chem Soc 135:15738-41
Johnson, Lisa M; Gellman, Samuel H (2013) ?-Helix mimicry with ?/?-peptides. Methods Enzymol 523:407-29
Boersma, Melissa D; Haase, Holly S; Peterson-Kaufman, Kimberly J et al. (2012) Evaluation of diverse ýý/ýý-backbone patterns for functional ýý-helix mimicry: analogues of the Bim BH3 domain. J Am Chem Soc 134:315-23
Steinkruger, Jay D; Bartlett, Gail J; Hadley, Erik B et al. (2012) The d'--d--d' vertical triad is less discriminating than the a'--a--a' vertical triad in the antiparallel coiled-coil dimer motif. J Am Chem Soc 134:2626-33
Mortenson, David E; Satyshur, Kenneth A; Guzei, Ilia A et al. (2012) Quasiracemic crystallization as a tool to assess the accommodation of noncanonical residues in nativelike protein conformations. J Am Chem Soc 134:2473-6
Almeida, Aaron M; Li, Rebecca; Gellman, Samuel H (2012) Parallel ?-sheet secondary structure is stabilized and terminated by interstrand disulfide cross-linking. J Am Chem Soc 134:75-8
Freire, Felix; Almeida, Aaron M; Fisk, John D et al. (2011) Impact of strand length on the stability of parallel-ýý-sheet secondary structure. Angew Chem Int Ed Engl 50:8735-8
Steinkruger, Jay D; Woolfson, Derek N; Gellman, Samuel H (2010) Side-chain pairing preferences in the parallel coiled-coil dimer motif: insight on ion pairing between core and flanking sites. J Am Chem Soc 132:7586-8
Price, Joshua L; Hadley, Erik B; Steinkruger, Jay D et al. (2010) Detection and analysis of chimeric tertiary structures by backbone thioester exchange: packing of an alpha helix against an alpha/beta-peptide helix. Angew Chem Int Ed Engl 49:368-71

Showing the most recent 10 out of 37 publications