Collagen, one of the most abundant proteins of the extracellular matrix, provides structural integrity in the human body and is responsible for multiple interactions with cells and other matrix molecules. Many common diseases, such as arthritis, diabetes, and cancer involve abnormal regulation or reactivity of collagen and certain collagen genetic diseases result in connective tissue disease or aortic aneurism. The objective of this proposal is to develop a mechanistic understanding of the interactions of the collagen ligand with its receptors and to understand the molecular basis of Osteogenesis Imperfecta (OI), a genetic disease that results in brittle bones. We propose to use an integrated approach based on NMR in conjunction with computational, biophysical methods, and in vitro functional assays to provide unique structural and dynamic insight these questions.
The specific aims of the proposal include 1) characterizing the structure and dynamics of the interactions between the integrin I domain and collagen;2) defining the sequence dependence and molecular mechanism of Gly mutations leading to collagen diseases: prediction of OI phenotype and 3) characterizing interactions of matrix metalloproteinases (MMPs) and integrin I-domain receptors with triple helical motifs that contain imperfect (GXY)n sequences at, or near, the binding regions. In order to achieve these aims we will develop some novel methodology designed to 1) achieve better structural and dynamic characterization of the collagen model peptides;these are long anisotropic molecules that are difficult to characterize by standard protocols and integration of NMR and MD simulations will provide a new approach for investigation of these unusual systems. 2) Using statistical approaches, develop consensus sequence patterns that define lethal and nonlethal phenotypes in OI;these will be used to begin to establish predictions of phenotype based on sequence and conformational fluctuations. The biomedical importance of collagen has led to increasing interest in the structural and biological role of this protein makin the collagen triple helix an extremely important target for probing sequence-structure-function relationships and for understanding the molecular basis of collagen/receptor biological interactions. Characterizing the collagen triple helix conformation and dynamics alone, and in combination with its binding partners, will help understand its role in disease and ligand recognition, and aid in drug discovery programs.
The tremendous biomedical importance of collagen makes the collagen triple helix an important target for establishing sequence-structure-function relationships to understand its structural and biological role. We will develop an integrated approach based on NMR in conjunction with computational, biophysical methods, and in vitro functional assays to provide insight into the recognition mechanism of the collagen triple helix with integrin and to understand the molecular basis of genetic collagen diseases arising from mutations. These studies will provide new insight into drug therapy approaches that target the unique triple helix motif.
|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|
|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|
|Kim, Seho; Wu, Kuen-Phon; Baum, Jean (2013) Fast hydrogen exchange affects Ã½Ã½Ã½Ã½Ã½N relaxation measurements in intrinsically disordered proteins. J Biomol NMR 55:249-56|
|Narayanan, Chitra; Weinstock, Daniel S; Wu, Kuen-Phon et al. (2012) Investigation of the Polymeric Properties of Ã½Ã½-Synuclein and Comparison with NMR Experiments: A Replica Exchange Molecular Dynamics Study. J Chem Theory Comput 8:3929-3942|
|Parmar, Avanish S; Nunes, Ana Monica; Baum, Jean et al. (2012) A peptide study of the relationship between the collagen triple-helix and amyloid. Biopolymers 97:795-806|
|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 Î±-synuclein. J Am Chem Soc 133:13465-70|
|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|
|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|
|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|
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