Open AccessExpression, purification, crystallization and preliminary X‐ray diffraction studies of the human keratin 4‐binding domain of serine‐rich repeat protein 1 from Streptococcus agalactiae
Author(s) -
Sundaresan Ramya,
Samen Ulrike,
Ponnuraj Karthe
Publication year - 2011
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309111040413
Subject(s) - streptococcus agalactiae , keratin , crystallization , crystallography , serine , domain (mathematical analysis) , chemistry , biology , materials science , microbiology and biotechnology , biochemistry , streptococcus , genetics , bacteria , enzyme , mathematical analysis , mathematics , organic chemistry
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 P 2 1 , with unit‐cell parameters a = 47.56, b = 59.48, c = 94.71 Å, β = 93.95°.