title: An induced folding process characterizes the partial-loss of function mutant LptAI36D in its interactions with ligands.
abstract: Lipopolysaccharide (LPS) is an essential glycolipid of the outer membrane (OM) of Gram-negative bacteria with a tripartite structure: lipid A, oligosaccharide core and O antigen. Seven essential LPS-transport proteins (LptABCDEFG) move LPS to the cell surface. Lpt proteins are linked by structural homology, featuring a β-jellyroll domain that mediates protein-protein interactions and LPS binding. Analysis of LptA-LPS interaction by fluorescence spectroscopy is used here to evaluate the contribution of each LPS moiety in protein-ligand interactions, comparing the wild-type (wt) protein to the I36D mutant. In addition to a crucial role of lipid A, an unexpected contribution emerges for the core region in recognition and binding of Lpt proteins.
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Santambrogio
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Sperandeo
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Barbieri
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy.
authors.forename: Alessandra M
authors.initials: AM
authors.lastname: Martorana
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy. Electronic address: alessandra.polissi@unimib.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Polissi
authors.affiliation: Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy. Electronic address: rita.grandori@unimib.it.
authors.forename: Rita
authors.initials: R
authors.lastname: Grandori
mesh_terms: D019943:Amino Acid Substitution; D000817:Anilino Naphthalenesulfonates; D001224:Aspartic Acid / Q000737:chemistry / Q000378:metabolism; D001692:Biological Transport; D002240:Carbohydrate Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D048168:Escherichia coli K12 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D007532:Isoleucine / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D017510:Protein Folding; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D000817:Anilino Naphthalenesulfonates; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008024:Ligands; D008070:Lipopolysaccharides; C532155:LptA protein, E coli; D011993:Recombinant Fusion Proteins; D007532:Isoleucine; D001224:Aspartic Acid; C027132:1-anilino-8-naphthalenesulfonate
keywords: 1-Anilino-8-naphthalene sulfonate; Binding site; Circular dichroism; Escherichia coli; Fluorescence spectroscopy; Lipopolysaccharide transport