Crystal structure of Escherichia coli SufC, an ABC-type ATPase component of the SUF iron-sulfur cluster assembly machinery.
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 2.5A 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.
Kitaoka
Shintaro
S
Department of Biology, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
Wada
Kei
K
Hasegawa
Yuko
Y
Minami
Yoshiko
Y
Fukuyama
Keiichi
K
Takahashi
Yasuhiro
Y
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000378:metabolism; D015502:Absorptiometry, Photon; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D019281:Dimerization; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013455:Sulfur / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D029968:Escherichia coli Proteins; D005973:Glutamine; D013455:Sulfur; D007501:Iron; D000251:Adenosine Triphosphatases; C507755:SufC protein, E coli