title: NMR monitoring of chain-specific stability in heterotrimeric collagen peptides.
abstract: NMR spectroscopy is used to investigate the heterotrimeric nature of a collagen model peptide. Two distinct peptide chains (A and B) were synthesized to model a site in heterotrimeric basement membrane type IV collagen. For NMR studies, four amino acids in the B chain were labeled with 15N/13C. Circular dichroism spectroscopy and differential scanning calorimetry thermal stability results on a solution with both A and B peptides (molar ratio 2A:1B) are consistent with the presence of one heterotrimeric triple-helical molecular species. Heteronuclear single quantum coherence experiments on homotrimers of the B peptide show trimer peaks which disappear at temperatures higher than 10 degrees C, while the 2A:1B mixture has trimer peaks with increased stability and altered chemical shifts. The reduction in the number of Leu trimer peaks from three to one and the increased stability of trimer resonances confirm the participation of B chains in an AAB heterotrimer molecule.
authors.affiliation: Department of Biochemistry, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
authors.forename: Balaraman
authors.initials: B
authors.lastname: Madhan
authors.forename: Jianxi
authors.initials: J
authors.lastname: Xiao
authors.forename: Geetha
authors.initials: G
authors.lastname: Thiagarajan
authors.forename: Jean
authors.initials: J
authors.lastname: Baum
authors.forename: Barbara
authors.initials: B
authors.lastname: Brodsky
mesh_terms: D000595:Amino Acid Sequence; D003094:Collagen / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D010455:Peptides; D003094:Collagen
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