title: 15N relaxation studies of Apo-Mts1: a dynamic S100 protein.
abstract: Mts1 is a member of the S100 family of EF-hand calcium-binding proteins. Like most S100 proteins, Mts1 exists as a dimer in solution and contains one canonical and one pseudo-EF-hand motif per monomer, each of which consists of two alpha helices connected by a loop capable of coordinating a calcium ion. The backbone dynamics of murine apo-Mts1 homodimer have been examined by nuclear magnetic resonance spectroscopy. Longitudinal and transverse relaxation data and steady-state (1)H- (15)N nuclear Overhauser effects were analyzed using model-free formalism. The extracted global correlation time is 9.94 ns. Results indicate that the protein backbone is most rigid at the dimer interface, made up of helices 1 and 4 from each monomer with mean S (2) ( S avg (2)) values approximately 0.9, flanked by helices 2 and 3 with lower S avg (2) values of 0.84 and 0.77, respectively. Each calcium-binding site along with the hinge joining the two EF-hands and the N- and C-termini are considerably more flexible than the dimer interface on a range of time scales and more flexible than the corresponding regions of other S100 proteins studied to date. As the hinge and the C-terminal tail are believed to interact with target proteins, these dynamic characteristics may have implications for Mts1 activity.
authors.affiliation: New York Structural Biology Center, 89 Convent Avenue, New York, New York 10033, USA. dutta@nysbc.org
authors.forename: Kaushik
authors.initials: K
authors.lastname: Dutta
authors.forename: Cathleen J
authors.initials: CJ
authors.lastname: Cox
authors.forename: Ravi
authors.initials: R
authors.lastname: Basavappa
authors.forename: Steven M
authors.initials: SM
authors.lastname: Pascal
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D064026:Calbindins; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009587:Nitrogen Isotopes; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry* / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009418:S100 Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D064026:Calbindins; D009587:Nitrogen Isotopes; D011994:Recombinant Proteins; D064030:S100 Calcium Binding Protein G; D009418:S100 Proteins