title: Expression, purification, crystallization and preliminary X-ray diffraction studies of the human keratin 4-binding domain of serine-rich repeat protein 1 from Streptococcus agalactiae.
abstract: Serine-rich repeat protein 1 (Srr-1) is a surface protein from Streptococcus agalactiae. A 17 kDa region of this protein has been identified to bind to human keratin 4 (K4) and is termed the Srr-1 K4-binding domain (Srr-1-K4BD). Recombinant Srr-1-K4BD was overexpressed in Escherichia coli BL21 (DE3) cells. Native and selenomethionine-substituted proteins were prepared using Luria-Bertani (LB) and M9 minimal media, respectively. A two-step purification protocol was carried out to obtain a final homogenous sample of Srr-1-K4BD. Crystals of native Srr-1-K4BD were obtained using PEG 3350 as a precipitant. The crystals diffracted to 3.8 Å resolution using synchrotron radiation and belonged to space group P2(1), with unit-cell parameters a = 47.56, b = 59.48, c = 94.71 Å, β = 93.95°.
authors.affiliation: Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Chennai, India.
authors.forename: Ramya
authors.initials: R
authors.lastname: Sundaresan
authors.forename: Ulrike
authors.initials: U
authors.lastname: Samen
authors.forename: Karthe
authors.initials: K
authors.lastname: Ponnuraj
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D003460:Crystallization; D018360:Crystallography, X-Ray; D015870:Gene Expression; D054730:Protein Interaction Domains and Motifs; D013292:Streptococcus agalactiae / Q000737:chemistry*
chemical_list: D018829:Adhesins, Bacterial; C524542:Srr-1 protein, Streptococcus agalactiae