title: Site-Resolved Backbone and Side-Chain Intermediate Dynamics in a Carbohydrate-Binding Module Protein Studied by Magic-Angle Spinning NMR Spectroscopy.
abstract: Magic-angle spinning solid-state NMR spectroscopy has been applied to study the dynamics of CBM3b-Cbh9A from Clostridium thermocellum (ctCBM3b), a cellulose binding module protein. This 146-residue protein has a nine-stranded β-sandwich fold, in which 35 % of the residues are in the β-sheet and the remainder are composed of loops and turns. Dynamically averaged (1) H-(13) C dipolar coupling order parameters were extracted in a site-specific manner by using a pseudo-three-dimensional constant-time recoupled separated-local-field experiment (dipolar-chemical shift correlation experiment; DIPSHIFT). The backbone-Cα and Cβ order parameters indicate that the majority of the protein, including turns, is rigid despite having a high content of loops; this suggests that restricted motions of the turns stabilize the loops and create a rigid structure. Water molecules, located in the crystalline interface between protein units, induce an increased dynamics of the interface residues thereby lubricating crystal water-mediated contacts, whereas other crystal contacts remain rigid.
authors.affiliation: School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv (Israel).
authors.forename: Hadar
authors.initials: H
authors.lastname: Ivanir-Dabora
authors.affiliation: School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv (Israel).
authors.forename: Evgeny
authors.initials: E
authors.lastname: Nimerovsky
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India). madhu@tifr.res.in.|TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500 075 (India). madhu@tifr.res.in.
authors.forename: P K
authors.initials: PK
authors.lastname: Madhu
authors.affiliation: School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv (Israel). amirgo@post.tau.ac.il.
authors.forename: Amir
authors.initials: A
authors.lastname: Goldbourt
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D048013:Acetivibrio thermocellus / Q000737:chemistry*; D018360:Crystallography, X-Ray; D056004:Molecular Dynamics Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D001426:Bacterial Proteins
keywords: NMR spectroscopy; carbohydrates; molecular dynamics; protein structures; proteins