title: Impact of natural variation in bacterial F17G adhesins on crystallization behaviour.
abstract: Since the introduction of structural genomics, the protein has been recognized as the most important variable in crystallization. Recent strategies to modify a protein to improve crystal quality have included rationally engineered point mutations, truncations, deletions and fusions. Five naturally occurring variants, differing in 1-18 amino acids, of the 177-residue lectin domain of the F17G fimbrial adhesin were expressed and purified in identical ways. For four out of the five variants crystals were obtained, mostly in non-isomorphous space groups, with diffraction limits ranging between 2.4 and 1.1 A resolution. A comparative analysis of the crystal-packing contacts revealed that the variable amino acids are often involved in lattice contacts and a single amino-acid substitution can suffice to radically change crystal packing. A statistical approach proved reliable to estimate the compatibilities of the variant sequences with the observed crystal forms. In conclusion, natural variation, universally present within prokaryotic species, is a valuable genetic resource that can be favourably employed to enhance the crystallization success rate with considerably less effort than other strategies.
authors.affiliation: Laboratorium voor Ultrastructuur, Vlaams Interuniversitair Instituut voor Biotechnologie and Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium.
authors.forename: Lieven
authors.initials: L
authors.lastname: Buts
authors.forename: Adinda
authors.initials: A
authors.lastname: Wellens
authors.forename: Inge
authors.initials: I
authors.lastname: Van Molle
authors.forename: Lode
authors.initials: L
authors.lastname: Wyns
authors.forename: Remy
authors.initials: R
authors.lastname: Loris
authors.forename: Martina
authors.initials: M
authors.lastname: Lahmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Oscarson
authors.forename: Henri
authors.initials: H
authors.lastname: De Greve
authors.forename: Julie
authors.initials: J
authors.lastname: Bouckaert
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000235:genetics*; D000595:Amino Acid Sequence; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray; D004187:Disaccharides / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics*; D014644:Genetic Variation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D018829:Adhesins, Bacterial; D004187:Disaccharides; D029968:Escherichia coli Proteins; C480724:F17-G adhesin protein, E coli