The broad long term objectives are twofold. One is to develop methods that will extend the power of solution NMR beyond the study of native globular proteins to the study of nonnative and nonglobular proteins. The second objective is to use NMR to understand protein folding mechanisms by studying structures of partially folded proteins, and by assessing the effect of amino acid substitutions on structure, stability and folding kinetics. These studies will form the basis for using NMR to understand how interruptions in the Gly-X-Y pattern, found in collagen diseases like Osteogenesis Imperfecta and Ehlers Danlos Syndrome, can result in serious disease.
The first aim i s to characterize the partially folded state of guinea pig alpha-lactalbumin to elucidate the nature of protein folding intermediates. More specifically, we wish to learn which regions of the molten globule state contain regions of secondary structure and whether tertiary interactions are important in stabilizing these regions of secondary structure. We will characterize the partially folded state by 1H NMR methods, and by isotope labelling and heteronuclear 2D and 3D NMR experiments. Key mutants will be made to assess the effects of sequence change on secondary structure and tertiary interactions of the partially folded state.
The second aim i s to obtain, for the first time, individual residue assignments and the NMR solution structure of triple helical peptides, to determine the role of individual amino acids in stabilizing the triple helix and to understand how key residues direct protein folding. We will examine the effects, by 1D NMR, of (Gly-X-Y) sequence changes on the amount of triple helix formed, and on the kinetics and thermodynamics of folding. To obtain the solution structure we will first design synthetic triple helical peptides to facilitate the spin system identification process. Then we propose 1H NMR experiments as well as heteronuclear NMR experiments that should allow us to perform sequential resonance assignments, and distinguish inter from intra strand NOE's.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29GM045302-01A1
Application #
3468298
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Project Start
1991-08-01
Project End
1996-07-31
Budget Start
1991-08-01
Budget End
1992-07-31
Support Year
1
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Rutgers University
Department
Type
Schools of Arts and Sciences
DUNS #
038633251
City
New Brunswick
State
NJ
Country
United States
Zip Code
08901
Xiao, Jianxi; Yang, Zhangfu; Sun, Xiuxia et al. (2015) Local amino acid sequence patterns dominate the heterogeneous phenotype for the collagen connective tissue disease Osteogenesis Imperfecta resulting from Gly mutations. J Struct Biol 192:127-37
Fu, Iwen; Case, David A; Baum, Jean (2015) Dynamic Water-Mediated Hydrogen Bonding in a Collagen Model Peptide. Biochemistry 54:6029-37
Xiao, Jianxi; Sun, Xiuxia; Madhan, Balaraman et al. (2015) NMR studies demonstrate a unique AAB composition and chain register for a heterotrimeric type IV collagen model peptide containing a natural interruption site. J Biol Chem 290:24201-9
Kim, Seho; Wu, Kuen-Phon; Baum, Jean (2013) Fast hydrogen exchange affects ýýýýýN relaxation measurements in intrinsically disordered proteins. J Biomol NMR 55:249-56
Kang, Lijuan; Wu, Kuen-Phon; Vendruscolo, Michele et al. (2011) The A53T mutation is key in defining the differences in the aggregation kinetics of human and mouse ?-synuclein. J Am Chem Soc 133:13465-70
Xiao, Jianxi; Cheng, Haiming; Silva, Teresita et al. (2011) Osteogenesis imperfecta missense mutations in collagen: structural consequences of a glycine to alanine replacement at a highly charged site. Biochemistry 50:10771-80
Xiao, Jianxi; Madhan, Balaraman; Li, Yingjie et al. (2011) Osteogenesis imperfecta model peptides: incorporation of residues replacing Gly within a triple helix achieved by renucleation and local flexibility. Biophys J 101:449-58
Wu, Kuen-Phon; Baum, Jean (2010) Detection of transient interchain interactions in the intrinsically disordered protein alpha-synuclein by NMR paramagnetic relaxation enhancement. J Am Chem Soc 132:5546-7
Xiao, Jianxi; Addabbo, Rayna M; Lauer, Janelle L et al. (2010) Local conformation and dynamics of isoleucine in the collagenase cleavage site provide a recognition signal for matrix metalloproteinases. J Biol Chem 285:34181-90
Wu, Kuen-Phon; Weinstock, Daniel S; Narayanan, Chitra et al. (2009) Structural reorganization of alpha-synuclein at low pH observed by NMR and REMD simulations. J Mol Biol 391:784-96

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