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Crystal structure of a DNA binding protein from the hyperthermophilic euryarchaeon Methanococcus jannaschii
Author(s) -
Wang Ganggang,
Guo Rong,
Bartlam Mark,
Yang Haitao,
Xue Hong,
Liu Yiwei,
Huang Li,
Rao Zihe
Publication year - 2003
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 - 10.1110/ps.03325103
Subject(s) - methanococcus , thermostability , crenarchaeota , dimer , protein structure , crystallography , crystal structure , structural biology , biology , archaea , chemistry , biochemistry , enzyme , gene , organic chemistry
The Sac10b family consists of a group of highly conserved DNA binding proteins from both the euryarchaeotal and the crenarchaeotal branches of Archaea. The proteins have been suggested to play an architectural role in the chromosomal organization in these organisms. Previous studies have mainly focused on the Sac10b proteins from the crenarchaeota. Here, we report the 2.0 Å resolution crystal structure of Mja10b from the euryarchaeon Methanococcus jannaschii . The model of Mja10b has been refined to an R ‐factor of 20.9%. The crystal structure of an Mja10b monomer reveals an α/β structure of four β‐strands and two α‐helices, and Mja10b assembles into a dimer via an extensive hydrophobic interface. Mja10b has a similar topology to that of its crenarchaeota counterpart Sso10b (also known as Alba). Structural comparison between the two proteins suggests that structural features such as hydrophobic inner core, acetylation sites, dimer interface, and DNA binding surface are conserved among Sac10b proteins. Structural differences between the two proteins were found in the loops. To understand the structural basis for the thermostability of Mja10b, the Mja10b structure was compared to other proteins with similar topology. Our data suggest that extensive ion‐pair networks, optimized accessible surface area and the dimerization via hydrophobic interactions may contribute to the enhanced thermostability of Mja10b.