title: Portrayal of complex dynamic properties of sugarcane defensin 5 by NMR: multiple motions associated with membrane interaction.
abstract: Defensins are essentially ancient natural antibiotics with potent activity extending from lower organisms to humans. Sd5 is a recently described antifungal defensin that appears to be the result of a recent gain of function. We reported here the solution NMR structure of Sd5 and characterized the backbone dynamics in the free state and in the presence of membrane models. (15)N relaxation dispersion measurements indicate intrinsic conformational exchange processes, showing two clear distinct k(ex), 490 and 1800 s(-1). These multiple motions may be related to transient twisting or breathing of the α helix and β sheet. The stages of membrane recognition and disruption by Sd5 over a large timescale range were mapped and demonstrated that Sd5 in solution sampled an ensemble of different conformations, of which a subset is selected upon membrane binding. Defensins share similar structures, but we demonstrated here that their dynamics can be extremely diverse.
authors.affiliation: Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas, Instituto de Bioquímica Médica, Rio de Janeiro, RJ 21941-902, Brazil.
authors.forename: Viviane Silva
authors.initials: VS
authors.lastname: de Paula
authors.forename: Guilherme
authors.initials: G
authors.lastname: Razzera
authors.forename: Eliana
authors.initials: E
authors.lastname: Barreto-Bergter
authors.forename: Fabio C L
authors.initials: FC
authors.lastname: Almeida
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Valente
mesh_terms: D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism*; D023082:Defensins / Q000737:chemistry* / Q000378:metabolism; D008823:Micelles; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D031786:Saccharum / Q000737:chemistry*
chemical_list: D023082:Defensins; D008823:Micelles; D010940:Plant Proteins