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Title
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The crystal structure of HasA, a hemophore secreted by Serratia marcescens.
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Authors
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P.Arnoux,
R.Haser,
N.Izadi,
A.Lecroisey,
M.Delepierre,
C.Wandersman,
M.Czjzek.
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Ref.
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Nat Struct Biol, 1999,
6,
516-520.
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PubMed id
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Abstract
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Free iron availability is strongly limited in vertebrate hosts, making the iron
acquisition by siderophores inappropriate. Pathogenic bacteria have developed
various ways to use the host's iron from iron-containing proteins. Serratia
marcescens can use the iron from hemoglobin through the secretion of a hemophore
called HasA, which takes up the heme from hemoglobin and shuttles it to the
receptor HasR, which in turn, releases heme into the bacterium. We report here
the first crystal structure of such a hemophore, bound to a heme group at two
different pH values and at a resolution of 1.9 A. The structure reveals a new
original fold and suggests a hypothetical mechanism for both heme uptake and
release.
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