title: Stretching polysaccharides on live cells using single molecule force spectroscopy.
abstract: The knowledge of molecular mechanisms underlying the adhesive and mechanical properties of cell surface-associated molecules is a key to understanding their functions. In this context, single-molecule force spectroscopy (SMFS) has recently offered new opportunities for probing the adhesion and mechanics of polysaccharides and proteins on live cells. Here we present a protocol that we have used to analyze polysaccharide chains of different nature on the bacterium Lactobacillus rhamnosus GG. We describe procedures (i) for functionalizing atomic force microscopy (AFM) tips with Pseudomonas aeruginosa-I or concanavalin A lectins, (ii) for stretching specific polysaccharide molecules on live bacteria using SMFS with lectin tips and (iii) for mapping the localization, adhesion and extension of individual polysaccharide chains. We also discuss data treatment, emphasizing how to gain insight into the elasticity of the stretched macromolecules using the extended freely jointed chain model. Even though the presented protocol is for L. rhamnosus, it can be easily modified for other cell types. For users having expertise in the field, the entire protocol can be completed in about 5 d.
authors.affiliation: Unité de Chimie des Interfaces, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Grégory
authors.initials: G
authors.lastname: Francius
authors.forename: David
authors.initials: D
authors.lastname: Alsteens
authors.forename: Vincent
authors.initials: V
authors.lastname: Dupres
authors.forename: Sarah
authors.initials: S
authors.lastname: Lebeer
authors.forename: Sigrid
authors.initials: S
authors.lastname: De Keersmaecker
authors.forename: Jos
authors.initials: J
authors.lastname: Vanderleyden
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Gruber
authors.forename: Yves F
authors.initials: YF
authors.lastname: Dufrêne
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development; D001696:Biomechanical Phenomena; D004548:Elasticity; D052201:Lacticaseibacillus rhamnosus / Q000378:metabolism*; D037102:Lectins; D008562:Membrane Glycoproteins / Q000378:metabolism; D018625:Microscopy, Atomic Force / Q000379:methods*; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D037102:Lectins; D008562:Membrane Glycoproteins; D011135:Polysaccharides, Bacterial; D029701:Saccharomyces cerevisiae Proteins; C025363:mannoproteins