2d2a

Publication Abstract from PubMed

IscA and SufA are paralogous proteins that play crucial roles in the biosynthesis of Fe-S clusters, perhaps through a mechanism involving transient Fe-S cluster formation. We have determined the crystal structure of E. coli SufA at 2.7A resolution. SufA exists as a homodimer, in contrast to the tetrameric organization of IscA. Furthermore, a C-terminal segment containing two essential cysteine residues (Cys-Gly-Cys), which is disordered in the IscA structure, is clearly visible in one molecule (the alpha1 subunit) of the SufA homodimer. Although this segment is disordered in the other molecule (the alpha2 subunit), computer modeling of this segment based on the well-defined conformation of alpha1 subunit suggests that the four cysteine residues (Cys114 and Cys116 in each subunit) in the Cys-Gly-Cys motif are positioned in close proximity at the dimer interface. The arrangement of these cysteines together with the nearby Glu118 in SufA dimer may allow coordination of an Fe-S cluster and/or an Fe atom.

Crystal structure of Escherichia coli SufA involved in biosynthesis of iron-sulfur clusters: implications for a functional dimer.,Wada K, Hasegawa Y, Gong Z, Minami Y, Fukuyama K, Takahashi Y FEBS Lett. 2005 Dec 5;579(29):6543-8. Epub 2005 Nov 15. PMID:16298366^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.