title: Crystallization and preliminary X-ray diffraction studies of mutants of B1 IgG-binding domain of protein L from Peptostreptococcus magnus.
abstract: The small 62-residue IgG-binding domain B1 of protein L from Peptostreptococcus magnus (Ppl-B1) has proven to be a simple system for the study of the thermodynamics and kinetics of protein folding. X-ray diffraction studies have been initiated in order to determine how the thermostability, folding and unfolding rates of a series of point mutations spanning Ppl-B1 correlate with the high-resolution structures. To this end, a tryptophan-containing variant of Ppl-B1 (herein known as wild type) and two mutants, Lys61Ala and Val49Ala, have been crystallized. Full data sets have been collected for the wild type and the Lys61Ala and Val49Ala mutants to resolutions of 1. 7, 2.3 and 1.8 A, respectively. Interestingly, all three crystallize using different precipitants and in different space groups. This may be a consequence of the relatively large effects of single-site mutations on surface-charge distribution or structural conformation, which might affect crystal contact sites.
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, PO Box 19024, Seattle, WA 98109, USA.
authors.forename: K
authors.initials: K
authors.lastname: Johnsen
authors.forename: J W
authors.initials: JW
authors.lastname: O'Neill
authors.forename: D E
authors.initials: DE
authors.lastname: Kim
authors.forename: D
authors.initials: D
authors.lastname: Baker
authors.forename: K Y
authors.initials: KY
authors.lastname: Zhang
mesh_terms: D000409:Alanine; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D001665:Binding Sites; D001666:Binding Sites, Antibody; D003460:Crystallization; D018360:Crystallography, X-Ray; D007074:Immunoglobulin G; D008239:Lysine; D016297:Mutagenesis, Site-Directed; D010462:Peptostreptococcus / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D014633:Valine
chemical_list: D001426:Bacterial Proteins; C055047:Ig L-binding protein, Peptostreptococcus; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D014633:Valine; D008239:Lysine; D000409:Alanine