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Crystal structure of Escherichia coli SufC, an ABC‐type ATPase component of the SUF iron–sulfur cluster assembly machinery
Author(s) -
Kitaoka Shintaro,
Wada Kei,
Hasegawa Yuko,
Minami Yoshiko,
Fukuyama Keiichi,
Takahashi Yasuhiro
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.11.058
Subject(s) - salt bridge , atp hydrolysis , atpase , nucleotide , chemistry , atp binding cassette transporter , escherichia coli , iron–sulfur cluster , stereochemistry , biochemistry , hydrolase , binding site , crystallography , biology , enzyme , transporter , gene , mutant
SufC is an ATPase component of the SUF machinery, which is involved in the biosynthesis of Fe–S clusters. To gain insight into the function of this protein, we have determined the crystal structure of Escherichia coli SufC at 2.5 Å resolution. Despite the similarity of the overall structure with ABC‐ATPases (nucleotide‐binding domains of ABC transporters), some key differences were observed. Glu171, an invariant residue involved in ATP hydrolysis, is rotated away from the nucleotide‐binding pocket to form a SufC‐specific salt bridge with Lys152. Due to this salt bridge, D‐loop that follows Glu171 is flipped out to the molecular surface, which may sterically inhibit the formation of an active dimer. Thus, the salt bridge may play a critical role in regulating ATPase activity and preventing wasteful ATP hydrolysis. Furthermore, SufC has a unique Q‐loop structure on its surface, which may form a binding site for its partner proteins, SufB and/or SufD.