Biochemistry, Department of
Document Type
Article
Date of this Version
2008
Citation
The Journal of Biological Chemistry, VOL. 283, NO. 22, pp. 15015–15022, May 30, 2008
Abstract
Sco1 is implicated in the copper metallation of the CuA site in
Cox2 of cytochrome oxidase. The structure of Sco1 in the metallated
and apo-conformers revealed structural dynamics primarily
in an exposed region designated loop 8. The structural
dynamics of loop 8 in Sco1 suggests it may be an interface for
interactions with Cox17, the Cu(I) donor and/or Cox2. A series
of conserved residues in the sequence motif 217KKYRVYF223 on
the leading edge of this loop are shown presently to be important
for yeast Sco1 function. Cells harboring Y219D, R220D, V221D,
and Y222D mutant Sco1 proteins failed to restore respiratory
growth or cytochrome oxidase activity in sco1∆ cells. The
mutant proteins are stably expressed and are competent to bind
Cu(I) and Cu(II) normally. Specific Cu(I) transfer from Cox17 to
the mutant apo-Sco1 proteins proceeds normally. In contrast,
using two in vivo assays that permit monitoring of the transient
Sco1-Cox2 interaction, the mutant Sco1 molecules appear compromised
in a function with Cox2. The mutants failed to suppress
the respiratory defect of cox17-1 cells unlike wild-type
SCO1. In addition, the mutants failed to suppress the hydrogen
peroxide sensitivity of sco1∆ cells. These studies implicate different
surfaces on Sco1 for interaction or function with Cox17
and Cox2.
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Comments
© 2008 by The American Society for Biochemistry and Molecular Biology, Inc.