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Crystal structure of the N ‐terminal domains of the surface cell antigen 4 of Rickettsia
Author(s) -
Lee Jun Hyuck,
Vonrhein Clemens,
Bricogne Gerard,
Izard Tina
Publication year - 2013
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.2322
Subject(s) - vinculin , rickettsia prowazekii , structural biology , cytoplasm , biology , protein structure , microbiology and biotechnology , chaperone (clinical) , chemistry , rickettsia , biophysics , biochemistry , cell , genetics , cytoskeleton , medicine , virus , pathology
The obligate intracellular, gram‐negative bacterium Rickettsia is the causative agent of spotted fevers and typhus in humans. Surface cell antigen (sca) proteins surround these bacteria. We recently reported the co‐localization of one of these proteins, sca4, with vinculin in cells at sites of focal adhesions and demonstrated that two vinculin binding sites directed the sca4/vinculin interaction. Here we report the 2.2 Å crystal structure of the conserved N ‐terminal 38 kDa domain of sca4 from Rickettsia rickettsii . The structure reveals two subdomains. The first is an all‐helical domain that is folded in a fashion similar to the dimeric assembly chaperone for rubisco, namely RbcX. The following and highly conserved β‐strand domain lacks significant structural similarity with other known structures and to the best of our knowledge represents a new protein fold.